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FIJI, SAMOA, SOLOMON ISLANDS & TONGA

162 Extension Fact Sheets

By members of ACIAR Projects IPPSI & ICM/IPM


April 2014 Produced with support of Improved Plant Protection in Solomon Islands and Strengthening integrated crop management research in the Pacific islands in support of sustainable intensification of high-value crop production, funded by the Australian Centre for International Agricultural Research (ACIAR), Canberra. The fact sheets were formatted using a design developed by Eric Boa and Jeffery Bentley of the Global Plant Clinic. The GPC is managed by CABI and is part of the Plantwise program, funded by the UK Department for International Development, Swiss Development Corporation and ACIAR.

Amena Banuve: [Stationamenabanuve@yahoo.com0

Sigatoka Research Station Ministry of Agriculture PO Box 24 Sigatoka Fiji

Aleni Uelese (aleni.uelese@maf.gov.ws) Nu’u Crop Research Centre Ministry of Agriculture and Fisheries PO Box 1874 Apia Samoa Helen Tsatsia [helen.tsatsia@yahoo.com] Ministry of Agriculture and Livestock P.O. Box G-13 Honiara Solomon Islands Sione Foliaki [sionekelo@gmail.com] Vaini Research Station PO Box 14 Ministry of Agriculture, Food, Forests and Fisheries Nuku’alofa Tonga Grahame Jackson [grahame@pestnet.org] 24 Alt Street Queens Park NSW 2022 Australia


Extension Fact Sheets 1

TARO

Alomae & Bobone

2

BANANA, PLANTAINS

Black Sigatoka

3

COCOA, COFFEE, OIL PALM, RUBBER,

Brown root rot

CABBAGE FAMILY, RADISH, WATERCRESS, AMARANTH

Diamond back moth

21

MANY CROPS

Fruit flies

22

FOREST TREES

4

CITRUS, OIL PALM, FOREST TREES

Butt & root rots

5

CHILLI

Virus disease

6

COCOA

Black pod & canker

7

WATERMELON,

Gummy stem blight

CANTALOUPE MELON, CUCUMBER

8

YAM, BANANA

Lesion nematodes

9

MANGO

Leaf spots & dieback (anthracnose)

10

TARO

Mitimiti disease

11

PEANUTS, SWEET POTATO, BEANS, TARO, TOMATO, MANY OTHERS

Athelia wilt

COCOA, CITRUS, MANGO, RUBBER,

Pink disease

12

20

FOREST TREES

13

SWEET POTATO

Scab

14

TARO

Leaf blight

23

SLIPERI KABIS OR BELE (Abelmoschus manihot), OKRA

SLIPERI KABIS OR BELE (Abelmoschus manihot), OKRA,

Flea beetle

Shoot borer

TOMATO

24

MANY CROPS

Spider mites

25

MANY CROPS

Spiraling whitefly

26

SWEET POTATO, BEANS, CUCUMBER, PEANUTS, PUMPKIN, WATERMELON, CABBAGE FAMILY

Flea hopper

27

SWEET POTATO, EGGPLANT, CAPSICUM, TOMATO, LEGUMES

Hornworm

28

SWEET POTATO, WILD IPOMOEA

Leaf folder

29

SWEET POTATO, WILD IPOMOEA

Weevil

30

TARO, BANANA, COCONUT, GIANT TARO, GIANT SWAMP TARO, OIL PALM, PANDANUS,

Papuana beetle

SUGARCANE

15

COCOA, MANGO

White thread disease

16

YAM

Leaf spots & dieback (anthracnose)

17

BANANA, PLANTAIN

Scab moth

18

BEANS, OTHER

Pod sucking bug

LEGUMES

19

CASSAVA, COCONUT EUCALYPTUS

Shoot dieback, premature nutfall

31

TARO, TOMATO, MANY OTHERS

Cluster caterpillar

32

TARO, SWEET POTATO, NONI

Hornworm

33

CUCUMBER, WATERMELON,

Cucumber moth

OTHERS IN CUCUMBER FAMILY


34

PEANUT FAMILY

Rust

35

MANY CROPS

Rats

36

PEANUT

Leaf spots

37

BEANS, OTHER LEGUMES

Pod borer

MANY CROPS,

Aphids

38

SLIPERI KABIS OR BELE (Abelmoschus

54

SWEET POTATO, KANGKONG

Sweet potato tortoise beetle

55

SWEET POTATO

Little leaf

56

PLANT-DERIVED

PDPs

PESTICIDES

WEEDS

39

KANGKONG

57

Leaf hopper

COCONUT, BETEL NUT, BANANA, SUGARCANE, WILD

Melanesian coconut beetle

PALMS

manihot

58 40

CUCUMBER,

59

TARO

Plant hopper

42

MAIZE, SWEET

Rust

CORN

44

BEANS, OTHER LEGUMES

COCONUT, BETEL NUT, SAGO PALM,

Coconut hispine beetle

OIL PALM

41

43

Ladybeetles

TOMATO

Pumpkin beetle

CANTALOUPE MELON, PUMPKIN, WATERMELON, OTHERS

EGGPLANT, BEANS,

60

COCONUT, BETEL NUT, SAGO PALM

Coconut leafminer

61

COCOA, FOREST

Cocoa weevil borer

TREES

Virus 62

KONGKONG TARO, TARO, MANY OTHERS

Root rot

45

TOMATO

Black leaf mould

46

MAIZE, SWEET

Boil smut

COCONUT, BETEL

Coconut spathe bug

NUT

63

CUCUMBER, CANTALOUPE, MELON, PUMPKIN, ZUCCHINI

Cucurbit powdery mildew

64

RICE, WILD GRASSES

Brown plant hopper

65

COCONUT, OTHER

Flat moth

CORN

47

MANY TYPES OF

Damping-off

PALMS

SEEDLINGS

48

CITRUS

Scab

49

CHILLI, CAPSICUM, MANY OTHERS

Broad mite

50

MANY CROPS

Giant African snail

51

MANY CROPS

Sooty mould

52

CHILLI, CASSAVA, CAPSICUM, SLIPERI

White peach scale

KABIS OR BELE

(Abelmoschus manihot)

53

SWEET POTATO,

Red sweet potato beetle

66

SOURSOP, COFFEE, CITRUS, GUAVA, CYCADS, MANY OTHERS

Brown coffee scale

67

BETEL NUT

Unknown ‘disease’

68

CASSAVA

Virus

69

COCONUT

Basal stem break

70

COCONUT, BANANA, TARO

Shoot rot, sheath rot, corm rot


71

BANANA, PLANTAIN

Black cross

90

COCONUT, BETEL NUT, OIL PALM, WILD PALMS

Leaf spots

72

BANANA,

Cordana leaf spot 91

CITRUS

Canker

92

PEPPER, CHILLI

Frog-eye leaf spot

93

YAM, GINGER, TARO, TURMERIC

Scale

94

TARO

Leaf spots

95

CASSAVA

Leaf spot

96

SWEET POTATO, KANGKONG, WILD IMPOMOEA

Flea beetle

Large cabbage-heart caterpillar

97

YAM

Rust

Hibiscus ringspot virus

98

MANY CROPS

Green vegetable bug

99

MANY CROPS

Turnip mosaic virus

100

MANY CROPS

Cucumber mosaic virus

PLANTAINS

73 74

SORGHUM MAIZE, SWEET

Bacterial leaf streak Virus

CORN

75

COCONUT

Seedling blight

76

TOMATO

Grey leaf mould

77

SUGARCANE,

Fiji disease

OTHER SACCHARUM SPECIES

78

79

80

CABBAGE FAMILY SLIPERI KABIS OR BELE (Abelmoschus manihot), HIBISCUS

MAIZE, SWEET CORN, SORGHUM

Maydis leaf blight

81

TOMATO, PEPPER

Bacterial spot

101

CHINESE CABBAGE

Bacterial stem rot

82

TOMATO, PEPPER, EGGPLANT, WATERMELON

Blossom end rot

102

COCONUT, PANDANUS, SAGO,

Coconut stick insect

83

MANY PESTS

Predatory ladybeetles

84

APHIDS ON MANY

Predatory hoverflies

OTHER PALMS

103

BANANA, TARO, GINGER, XANTHOSOMA

Banana aphid

104

COCONUT, BANANA, AVOCADO, GUAVA, BREADFRUUIT, CASSAVA, OIL PALM, SUGARCANE

Coconut scale

105

CITRUS

Citrus snow scale

106

BEANS, CABBAGE, CAPSICUM, CUCUMBER, EGGPLANT, MELON, POTATO, TOMATO

Melon thrips

CROPS

85

CAPSICUM, CHILLI, TOMATO,

Sunscald

EGGPLANT

86

87

TOMATO, PEPPER, MANY OTHERS SLIPERI KABIS OR BELE (Abelmoschus

Thrips

Cotton leaf roller

manihot), OKRA

88

TARO, OTHER EDIBLE AROIDS

Dasheen mosaic virus

89

TARO

Rhabdoviruses

ZUCCHINI


107

COCOA, COFFEE, ORNAMENTALS, YAMS, OTHERS

Rose beetle

COCONUT, SAGO, OIL PALM, TREE FERN, OTHER PALMS

Rhinoceros beetle

BANANA, MANILA HEMP

Banana weevil

110

CUCUMBER, BEAN, POTATO, BRASSICA FAMILY

Leafminers

111

COCONUT, OIL PALM, OTHER PALMS

Coconut spike moth

COTTON, BEANS, MAIZE, SORGHUM, TOMATO, MANY OTHERS

Corn earworm

BANANA, CITRUS, 5CORNER FRUIT, GUAVA, PASSION FRUIT, PINEAPPLE, TOMATO, MELON, CAPSICUM, OTHERS

Fruit piercing moth

CABBAGE, CHINESE CABBAGE, RADISH CAULIFLOWER,

Cabbage webworm

115

MAIZE, SWEET CORN, GINGER, SORGHUM, OTHERS

Asian corn borer

116

COCONUT, PANDANUS

Coconut termite

117

ONIONS, BRASSICAS, CUCUMBER, MELON, SQUASH, LEGUMES, TOMATO, POTATO, OTHERS

Onion thrips

118

COFFEE

Coffee berry borer

119

SWEET POTATO, WILD IPOMOEA

West Indian sweet potato weevil

120

AVOCADO, PINEAPPLE, TREES, ORNAMENTALS, MANY OTHERS

Avocado dieback

108

109

112

113

114

121

BANANA

Banana bunchy top

122

BANANA

Banana Malayan leaf spot

123

BANANA

Banana leaf rust

124

BANANA

Banana freckle

125

BANANA

Banana black end rot

126

CABBAGE, CARROT, LEGUMES, POTATO, TOMATO, MANY OTHERS

Rhizoctonia web blight

127

VEGETABLES, FRUIT CROPS,

Root-knot nematode

ORNAMENTALS

128

BEANS, CAPSICUM, CUCUMBER, TOMATO, OTHERS

Pythium cottony leak (and damping-off)

129

VEGETABLES, FRUIT CROPS,

Sclerotinia rots & blights

ORNAMENTALS

130

BEADFRUIT, COCOA, COCONUT, AVOCADO, CITRUS, PAPAYA

Breadfruit fruit rot

131

CABBAGE, CHINESE CABBAGE, BROCCOLI, CAULIFLOWER

Cabbage black rot

132

CABBAGE, CHINESE CABBAGE, BROCCOLI, CAULIFLOWER

Fusarium wilt brassicas

133

CABBAGE, CHINESE CABBAGE, BROCCOLI, CAULIFLOWER

Alternaria leaf spot

134

CABBAGE, CHINESE CABBAGE, BROCCOLI, CAULIFLOWER

Cabbage white rust

135

CARROT, PARSLEY, CELERY

Carrot leaf spot


136

CELERY

Celery early blight

137

COCOA

Cocoa sunscald & Cherelle wilt

138

SWEET POTATO

Sweet potato gall mite

139

COCONUT

Coconut leaf stripe

140

COCONUT, BETEL NUT, OTHERS

Coconut bud rot

141

COFFEE

Coffee rust

142

COFFEE

Coffee berry spot

143

CUCUMBER, MELON, PUMPKIN, SQUASH, WATERMELON,

Cucumber downy mildew

152

PAPAYA, BEADFRUIT, COCOA, COCONUT, FRUIT CROPS

Papaya fruit & root rot

153

PASSION FRUIT, GRANADILLA, WEEDS

Passionfruit spot

154

PASSIONFRUIT, TOMATO, CAOSICUM, CITRUS, PAPAYA, PINEAPPLE

Passionfruit blight & wilt

155

PASSIONFRUIT, WEEDS

Passionfruit collar rot

156

PASSIONFRUIT

Passionfruit viruses

157

TOMATO, PASSIONFRUIT, BELE (Abelmoschus manihot), CAPSICUM, CITRUS, PAPAYA, PINEAPPLE

Tomato fruit & root rot

158

PAPAYA

Papaya black spot

159

VANILLA, ORNAMENTAL ORCHIDS

Vanilla viruses

160

KAVA, MANY OTHERS

Kava dieback

161

GINGER, BANANA, PEPPER, COFFEE, COCONUT, BETEL NUT, OTHERS

Ginger - nematode

162

GINGER, TARO, GIANT TARO, GIANT XANTHOSOMA, BEANS, CAPSICUM, OTHERS

Ginger - soft rot (and damping-off)

ZUCCHINI

144

CUCUMBER, SQUASH, ZUCCHINI, CAPSICUM, WATERMELON, PAPAYA, OTHERS

Cucurbit wet rot

WATERMELON, CUCUMBER, MELON, PUMPKIN, SQUASH, ZUCCHINI

Cucurbit leaf spot

TOMATO, CAPSICUM, EGGPLANT, CHILLI, MANY OTHERS

Bacterial wilt

147

EGGPLANT

Eggplant leaf spot

148

AVOCADO, CITRUS, BREADFRUIT, COCOA, COFFEE, GUAVA, MANGO, VANILLA, OTHERS

Algal leaf spots

149

SLIPERI KABIS, BELE

(Abelmoschus manihot)

Phytophthora wilt bele

150

LETTUCE

Lettuce leaf spot

151

ONION, GARLIC, LEEK, SHALLOT

Onion purple blotch

145

146


Crops and problems AMARANTH FS20 Diamond back moth AVOCADO FS104 Coconut scale FS120 Avocado dieback FS130 Breadfruit fruit rot FS148 Algal leaf spots FS152 Papaya fruit & root rot BANANA & PLANTAINS FS02 Black Sigatoka FS08 Lesion nematodes FS17 Scab moth FS30 Papuana beetles FS57 Melanesian coconut beetle FS70 Sheath rot FS71 Black cross FS72 Cordana (Diamond) leaf spot FS103 Banana aphid FS104 Coconut scale Fs105 Citrus snow scale FS109 Banana weevil FS111 Coconut spike moth FS113 Fruit piercing moth FS121 Banana bunchy top FS122 Banana Malayan leaf spot FS123 Banana leaf spot FS124 Banana freckle FS125 Banana black end rot FS127 Root-knot nematode FS161 Ginger - nematode BEANS & OTHER LEGUMES FS11 Athelia wilt FS18 Pod sucking bug FS26 Flea hopper FS27 Hornworm FS37 Pod borer FS43 Virus FS58 Ladybird beetles FS98 Green vegetable bug FS106 Melon thrips FS110 Leafminers FS112 Corn earworm FS117 Onion thrips FS126 Rhizoctonina web blight FS127 Root-knot nematode FS128 Pythium cottony leak (& damping-off) FS129 Sclerotinia rots & blights FS162 Ginger – soft rot (& damping-off)

BETEL NUT & WILD PALMS FS57 Melanesian coconut beetle FS59 Hispine beetle FS60 Leafminer FS62 Spathe bug FS65 Flat moth FS67 Betel nut ‘disease’ FS90 Leaf spots FS111 Coconut spike moth FS140 Coconut bud rot FS161 Ginger - nematode BREADFRUIT FS104 Coconut scale FS130 Breadfruit fruit rot FS148 Algal leaf spots FS152 Papaya fruit & root rot CABBAGE FAMILY (BRASSICAS) FS20 Diamond back moth FS26 Flea hopper FS78 Large cabbage-heart caterpillar FS99 Turnip mosaic virus FS101 Bacterial stem rot FS106 Melon thrips FS110 Leafminers FS114 Cabbage webworm FS117 Onion thrips FS126 Rhizoctonia web blight FS129 Sclerotinia rots & blights FS131 Cabbage black rot FS132 Fusarium yellows - brassicas FS133 Cabbage leaf spot FS134 Cabbage white rust


CAPSICUM (SWEET PEPPER) FS27 Hornworm FS49 Broad mite FS52 White peach scale FS81 Bacterial spot FS82 Blossom end rot FS85 Sunscald FS86 Thrips FS92 Frog-eye leaf spot FS100 Cucumber mosaic virus FS106 Melon thrips FS110 Leafminers FS113 Fruit piercing moth FS127 Root-knot nematode FS128 Pythium cottony leak FS129 Sclerotinia rots & blights FS144 Cucurbit wet rot FS146 Bacterial wilt FS149 Phytophthora wilt - bele FS154 Passionfruit blight & wilt FS157 Tomato fruit & root rot FS162 Ginger - soft rot (& damping-off) CARAMBOLA FS113 Fruit piercing fruit CARROT FS126 Leaf or Seedling blight FS127 Root-knot nematode FS135 Carrot leaf spot CASSAVA FS19 Shoot dieback bug (Amblypelta) FS52 White peach scale FS68 Virus FS95 Brown leaf spot FS104 Coconut scale CELERY FS110 Leafminers FS129 Sclerotinia rots & blights FS135 Carrot leaf spot FS136 Celery early blight CHILLI FS05 Virus FS49 Broad mite FS52 White peach scale FS92 Frog-eye leaf spot FS100 Cucumber mosaic virus

CITRUS FS04 Butt and root rot FS12 Pink disease FS48 Scab FS66 Brown coffee scale FS91 Canker FS105 Citrus scale FS113 Fruit piercing moth FS130 Breadfruit fruit rot FS148 Algal leaf spots FS149 Phytophthora wilt - bele FS152 Papaya fruit & root rot FS157 Tomato fruit & root rot COCOA FS03 Brown root rot FS06 Phytophthora black pod & canker FS12 Pink disease FS15 White thread disease FS61 Weevil borer FS107 Rose beetle FS130 Breadfruit fruit rot FS152 Papaya fruit & root rot FS137 Sunscald & Cherelle wilt FS148 Algal leaf spots COCONUT & OTHER PALMS FS19 Premature nutfall (Amblypelta) FS30 Papuana beetles FS57 Melanesian coconut beetle FS59 Hispine beetle FS60 Leafminer FS62 Spathe bug FS65 Flat moth FS69 Basal stem break FS70 Embryo rot FS75 Seedling blight FS90 Leaf spots FS102 Stick insects FS104 Coconut scale FS108 Rhinoceros beetle FS111 Coconut spike moth FS116 Coconut termite FS130 Breadfruit fruit rot FS139 Coconut leaf stripe FS140 Coconut bud rot FS152 Papaya fruit & root rot FS161 Ginger - nematode


COFFEE FS03 Brown root rot FS66 Brown coffee scale FS107 Rose beetle FS118 Coffee berry borer FS141 Leaf rust FS142 Coffee berry spot FS148 Algal leaf spots Fs161 Ginger - nematode COTTON FS112 Corn earworm CUCUMBER FS07 Gummy stem blight FS26 Flea hopper FS33 Cucumber moth FS40 Pumpkin beetle FS63 Powdery mildew FS106 Melon thrips FS110 Leafminers FS117 Onion thrips FS127 Root-knot nematode FS128 Pythium cottony leak (& damping-off) FS143 Cucumber downy mildew FS144 Cucurbit wet rot FS145 Cucurbit leaf spot CYCAD FS66 Brown coffee scale CYRTOSPERMA

FS88 Dasheen mosaic virus EGGPLANT FS19 Shoot dieback (Amblypelta) FS27 Hornworm FS58 Ladybeetles FS82 Blossom end rot FS85 Sunscald FS106 Melon thrips FS127 Root-knot nematode FS147 Eggplant leaf spot FOREST TREES FS03 Brown root rot FS04 Butt & root rots FS12 Pink disease FS61 Weevil borer FS120 Avocado dieback GARLIC FS151 Purple blotch

GIANT SWAMP TARO (CYRTOSPERMA) FS88 Dasheen mosaic virus FS30 Papuana beetles FS161 Ginger - nematode GIANT TARO (ALOCASIA) FS30 Papuana beetles FS88 Dasheen mosaic virus FS162 Ginger - soft rot (& damping-off) GINGER FS93 Yam scale FS103 Banana aphid FS115 Asian corn borer FS127 Root-knot nematode FS161 Ginger - nematode FS162 Ginger – soft rot (& damping-off) GUAVA FS66 Brown coffee scale FS104 Coconut scale FS113 Fruit piercing fruit FS148 Algal leaf spots KANGKONG FS53 Red beetle FS54 Tortoise beetle FS96 Flea beetle KAVA FS160 Kava dieback KONGKONG TARO (XANTHOSOMA) FS44 Root rot FS88 Dasheen mosaic virus FS103 Banana aphid FS162 Soft rot (& damping-off) LEEK FS151 Onion purple blotch LETTUCE FS127 Root-knot nematode FS129 Sclerotinia rots & blights FS150 Lettuce leaf spot MAIZE, SWEET CORN FS42 Rust FS46 Boil smut FS74 Virus FS80 Maydis leaf blight FS112 Corn earworm FS115 Asian corn borer


MANGO FS09 Leaf spot and dieback FS12 Pink disease FS15 White thread disease FS148 Algal leaf spots MELON - CANTALOUPE FS07 Gummy stem blight FS40 Pumpkin beetle FS63 Powdery mildew FS106 Melon thrips FS113 Fruit piercing moth FS117 Onion thrips FS127 Root-knot nematode FS143 Cucumber downy mildew FS145 Cucurbit leaf spot NONI FS32 Hornworm OIL PALM FS03 Brown root rot FS04 Butt and root rot FS30 Papuana beetles FS57 Melanesian coconut beetle FS59 Hispine beetle FS90 Leaf spots FS104 Coconut scale FS108 Rhinoceros beetle FS111 Coconut spike moth OKRA FS22 Flea beetle FS23 Shoot borer FS87 Cotton leaf roller ONION FS117 Onion thrips FS151 Purple blotch PANDANUS FS30 Papuana beetles FS102 Coconut stick insects FS116 Coconut termite PAPAYA FS127 Root-knot nematode FS130 Breadfruit fruit rot FS144 Cucurbit wet rot FS149 Phytophthora wilt - bele FS152 Papaya fruit & root rot FS154 Passionfruit blight & wilt FS157 Tomato fruit & root rot FS158 Papaya black spot

PARSLEY FS135 Carrot leaf spot PASSIONFRUIT & GRANADILLA FS113 Fruit piercing moth FS149 Phytophthora wilt - bele FS153 Passionfruit spot FS154 Passionfruit blight & wilt FS155 Passionfruit collar rot FS156 Passionfruit woodiness virus FS157 Phytophthora fruit & root rot PEANUT FS11 Athelia wilt FS22 Flea hopper FS34 Rust FS36 Leaf spots FS129 Sclerotinia rots & blight PEPPER FS161 Burrowing nematode PINEAPPLE FS113 Fruit piercing moth FS120 Phytophthora root rot FS127 Root-knot nematode FS149 Phytophthora wilt – bele FS154 Passionfruit blight & wilt FS157 Phytophthora root & fruit rot POTATO FS106 Melon thrips FS110 Leafminers FS117 Onion thrips FS126 Rhizoctonia web blight FS127 Root-knot nematode FS129 Sclerotinia rots & blights PUMPKIN FS26 Flea hopper FS40 Pumpkin beetle FS63 Powdery mildew FS10 Cucumber mosaic virus FS143 Cucumber downy mildew FS145 Cucurbit leaf spot RICE & WILD GRASSES FS64 Brown plant hopper RUBBER FS03 Brown root rot FS12 Pink disease


SAGO PALM FS59 Hispine beetle FS60 Leafminer FS102 Stick insects FS108 Rhinoceros beetle SHALLOT FS117 Onion thrips FS151 Onion purple blotch SLIPERI KABIS (Aibeka, Bele) & HIBISCUS FS22 Flea beetle FS23 Shoot borer FS39 Leaf hopper FS52 White peach scale FS79 Hibiscus ringspot virus FS87 Cotton leaf roller FS149 Phytophthora wilt - bele FS157 Tomato fruit & root rot SNAKE GOURD FS100 Cucumber mosaic virus SORGHUM & WILD GRASSES FS73 Bacterial leaf streak FS80 Maydis leaf blight FS112 Corn earworm FS115 Asian corn borer SOURSOP FS66 Brown coffee scale SQUASH FS63 Cucurbit powdery mildew FS117 Onion thrips FS143 Cucumber downy mildew FS144 Cucurbit wet rot FS145 Cucurbit leaf spot SUGARCANE & OTHER SACCHARUM SPECIES FS30 Papuana beetles FS57 Melanesian coconut beetle FS77 Sugarcane Fiji disease FS104 Coconut scale SUNFLOWER FS129 Sclerotinia rots & blights

SWEET POTATO & WILD IPOMOEA FS11 Athelia wilt FS13 Scab FS26 Flea hopper FS27 Hornworm FS28 Leaf folder FS29 Weevil FS32 Hornworm FS53 Red beetle FS54 Tortoise beetle FS55 Little leaf FS96 Flea beetle FS119 West Indian sweet potato weevil FS138 Sweet potato gall mite TARO FS01 Alomae & Bobone FS10 Mitimiti disease FS11 Athelia wilt FS14 Leaf blight FS30 Papuana beetles FS31 Cluster caterpillar FS32 Hornworm FS41 Plant hopper FS44 Root rot FS70 Marasmiellus corm rot FS89 Rhabdoviruses FS93 Yam scale FS94 Leaf spots FS162 Ginger - soft rot (& damping-off) TOMATO FS11 Athelia wilt FS23 Shoot borer FS27 Hornworm FS31 Cluster caterpillar FS45 Black leaf mould FS58 Ladybird beetles FS76 Grey leaf mould FS81 Bacterial spot FS82 Blossom end rot FS85 Sunscald FS86 Thrips FS100 Cucumber mosaic virus FS106 Melon thrips FS110 Leafminers FS112 Corn earworm FS113 Fruit piercing moth FS117 Onion thrips FS126 Rhizoctonia web blight FS127 Root-knot nematode FS128 Pythium cottony leak (& damping-off) FS129 Sclerotinia rots & blights FS146 Bacterial wilt FS149 Phytophthora wilt - bele FS154 Passionfruit blight & wilt FS157 Tomato fruit & root rot


TREE FERN FS108 Rhinoceros beetle TURMERIC FS93 Yam scale VANILLA FS148 Algal leaf spots FS159 Vanilla viruses WATERCRESS FS20 Diamond back moth FS26 Flea hopper WATERMELON FS07 Gummy stem blight FS33 Cucumber moth FS40 Pumpkin beetle FS82 Blossom-end rot FS100 Cucumber mosaic virus FS110 Leafminers FS143 Cucumber downy mildew FS144 Cucurbit wet rot FS145 Cucurbit leaf spot YAM FS08 Lesion nematodes FS16 Leaf spot and dieback FS97 Rust FS93 Yam scale FS107 Rose beetle FS127 Root-knot nematode ZUCCHINI FS63 Powdery mildew FS106 Melon thrips FS143 Cucumber downy mildew FS144 Cucurbit wet rot FS145 Cucurbit leaf spot

PROBLEMS OF MANY CROPS & WEEDS FS11 Athelia wilt FS12 Pink disease FS21 Fruit flies FS24 Spider mites FS25 Spiraling whitefly FS31 Cluster caterpillar FS35 Rats FS38 Aphids FS44 Root rot FS47 Damping-off FS49 Broad mite FS50 Giant African snail FS51 Sooty mould FS56 Plant-derived pesticides FS66 Brown coffee scale FS86 Thrips FS98 Green vegetable bug FS99 Turnip mosaic virus FS100 Cucumber mosaic virus FS106 Melon thrips FS107 Rose beetle FS112 Corn earworm FS113 Fruit piercing moth FS115 Asian corn borer FS117 Onion thrips FS120 Avocado dieback FS127 Root-knot nematode FS129 Sclerotinia rots & blights FS144 Cucurbit wet rot FS146 Bacterial wilt FS148 Algal leaf spots PREDATORY INSECTS (BIOCONTROL AGENTS) FS83 Predatory ladybeetles FS84 Hoverflies


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Extension Fact sheet

Alomae & Bobone

1

Common names:  Alomae  and  Bobone     Scientific  name:  Colocasia  bobone  rhabdovirus;  Taro  vein  chlorosis  virus;  Taro  badnavirus.   Hosts:  Colocasia  bobone  rhabdovirus  and  Taro  vein  chlorosis  virus  have  only  been  recorded   from  taro  (Colocasia);  Taro  badnavirus  has  been  recorded  from  kongkong  taro  (Xanthosoma)   and  edu  (vili,  nepa)  (Alocasia),  but  not  in  Solomon  Islands.    

Damage Alomae  (photo,  left)  is  a  deadly  disease  that  has  had  a  huge  impact  on  taro  production  in   Solomon  Islands.  Most  taros  are  susceptible.  On  Malaita,  those  taro  are  called  ‘male’.  The   impact  has  been  worse  on  Malaita  than  on  other  islands.  Previously,  the  disease  was  kept  in   check  by  strict  cultural  practices.  Nowadays,  it  is  very  difficult  to  grow  ‘male’  taro  in  the   lowlands.  In  recent  years,  the  disease  has  spread  to  other  islands  where  it  has  been   devastating,  such  as  the  Weather  Coasts  of  Guadalcanal  and  Makira.  It  is  not  unusual  in  these   places  for  entire  gardens  to  be  destroyed  by  Alomae.     Bobone  (photos,  centre  &  right)  does  not  kill  taro;  it  reduces  the  yield  by  about  25  per  cent.   Plants  usually  start  to  produce  healthy  leaves  after  4-­‐6  weeks,  and  then  appear  normal.  The   disease  only  occurs  in  a  few  varieties  of  taro.  These  are  called  ‘female’  taro  on  Malaita.  They   are  resistant  to  Alomae.  

Biology and  Life  Cycle   Insects  (photo,  right)  spread  the  viruses  that  cause  Alomae  and  Bobone:     • The  rhabdovirus  is  spread  by  Tarophagus,  a  planthopper;   • The  badnavirus  is  spread  by  Planococcus  and  Pseudococcus;  these  are  mealybugs.       The  planthoppers  and  mealy  bugs  suck  up  the  viruses  as  they  feed;  the  viruses  multiply  in  the   insects,  which  then  spread  them  as  they  move  and  feed  on  healthy  plants.     When  ‘male’  plants  are  infected  by  the  rhabdovirus,  the  plants  develop  Alomae,  and  die.   When  ‘female’  plants  are  infected  by  the  rhabdovirus,  they  develop  Bobone,  but  they  recover.     Apart  from  being  spread  by  insects,  the  viruses  are  also  spread  in  planting  material.  It  is  likely   that  all  taro  are  infected  with  Taro  badnavirus,  without  showing  symptoms,  or  only  rarely  do   they  show  symptoms.  The  viruses  spread  from  mother  plants  to  suckers.  Also,  it  is  likely  that   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   all  ‘female’  taro  are  infected  with  the  rhabdovirus.  Bobone  often  occurs  after  planting,  when   plant  hoppers  are  absent.  Possibility,  stress  at  planting  causes  the  virus  to  multiply.  Alomae  is   spread  from  one  garden  to  another  in  diseased  ‘tops’  and  suckers  used  for  planting.  

Detection and  Inspection   It  is  important  to  inspect  taro  gardens  regularly.  Look  at  the  youngest  leaves.  If  the  plant  has   Alomae,  the  leaf  will  be:   • Stunted,  slightly  curled,  bent  backwards,  crinkled,  and  often  paler  than  older  leaves.       If  the  plant  has  Bobone,  the  leaf  will  be:   • Stunted,  thickened,  curled  or  partly  curled,  darker  green  than  usual,  and  the  leaf  stalks  will   have  galls  –  small  outgrowths.     Plants  with  Alomae  stop  growing  and  the  youngest  leaf  remains  rolled  and  yellow.  Plants  with   Bobone  produce  leaves  that  are  stunted  and  distorted,  and  then  healthy  leaves  develop.  

Management CULTURAL  CONTROL   Alomae  is  best  controlled  by  cultural  methods.  These  methods  rely  on  farmers’  understanding   how  the  disease  spreads.  It  is  very  important  that  farmers:     • Understand  that  insects  spread  Alomae,  as  they  fly  between  plants  and  gardens;     • Work  together,  each  one  applying  the  methods  in  his  or  her  garden;   • A  village  group  is  formed,  which  meets  regularly,  exchanges  ideas,  and  the  members  help   each  other;   • Plant  resistant  varieties:  ‘Female’  taros  are  resistant  to  Alomae,  and  they  can  be  used   where  the  disease  is  severe,  especially  in  the  lowlands.     Farmers  should  do  the  following:     • Make  new  gardens  as  far  away  from  old  ones  as  possible;     • Avoid  taking  planting  material  from  diseased  to  new  gardens;   • Pull  out  Alomae  plants  carefully,  making  sure  that  any  planthoppers  are  trapped  in  the   leaves  or  between  the  stalks  –  or  put  a  rice  bag  over  the  plants  before  pulling  them  out  -­‐   then  burn  them;   • DO  NOT  pull  out  plants  and  leave  them  in  the  garden  or  throw  them  into  the  bush  –  the   insects  will  come  back  again.    

BIOLOGICAL CONTROL   Cyrtorhinus,  a  bug  that  feeds  on  the  eggs  of  Tarophagus,  reduces  the  population  of  the  plant   hopper,  but  experience  shows  that  it  is  not  enough  to  stop  the  spread  of  Alomae.    

CHEMICAL CONTROL   Regular  spraying  with  pyrethroid  insecticides  (permethrin  or  lambda  cyhalothrin)  will  kill   Tarophagus  and  reduce  Alomae.  It  will  not  prevent  Bobone.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Black Sigatoka    

Extension Fact  Sheet  

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Common names:  Black  Sigatoka,  Black  leaf  streak   Scientific  name:  Mycosphaerella  fijiensis.   Hosts:  The  fungus  infects  bananas  and  plantains,  Musa  species.    

Damage Red-­‐brown  streaks  appear  on  the  underneath  of  the  third  or  forth  youngest  leaf.  These  form   long  spots  with  grey  or  light  brown  centres  and  dark  brown  or  black  margins  (photo,  right).  The   spots  join  together,  often  with  yellow  areas  between.  The  infected  areas  invariably  form  bands   several  centimetres  wide  on  either  side  of  the  midrib.  In  severe  infections,  spots  do  not  occur,   but  large  areas  of  the  leaf  turn  black  and  die.  Generally,  the  streaks  are  more  common  at  the   tips  and  edges  of  the  leaves  (photo,  left).     The  effect  of  the  disease  is  a  loss  of  leaves:  leaves  die  early.  Instead  of  lasting  200  days  they   last  only  50.  This  reduces  yield  by  35-­‐50%,  depending  on  severity  of  the  infection  and  on  the   variety.  Cavendish  varieties  are  particularly  susceptible  and  these  are  grown  for  sale   worldwide.  About  30%  of  the  production  costs  in  commercial  plantations  are  spent  on   fungicides  to  control  the  disease.     The  weight  of  the  bunch  and  the  ripening  of  the  fruit  are  affected  by  the  number  of  leaves  on   the  plant:  if  too  few  at  flowering  then  bunch  weight  is  low;  if  less  than  five  leaves  at  harvest,   the  fruits  ripen  early.  

Biology and  Life  Cycle   Spores  are  produced  in  the  dead,  grey  areas  on  the  upper  leaf  surface.  The  fungus  has  two   type:  ascospores  and  conidia  (see  diagram1).  The  ascospores  are  the  more  important.  They  are   released  from  the  upper  leaf  surface  during  rain  or  high  humidity.  They  travel  by  air  currents   or  rain  splash,  and  land  on  the  underside  of  the  emerging  leaves.  The  spores  germinate  and   1

The  diagram  of  the  life  cycle  is  from  APSnet  Education  Center.    Back  Sigatoka  of  bananas  and  plantains.  The  permission  of  The   American  Phytopathological  Society  to  use  this  diagram  is  gratefully  acknowledged.   http://www.apsnet.org/edcenter/intropp/lessons/fungi/ascomycetes/Pages/BlackSigatoka.aspx     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   the  germ  tubes  enter  through  natural  openings  in  the  leaf.  The  fungus  grows  within  the  leaf,   killing  plant  cells,  before  returning  to  the  surface  to  produce  more  spores.  Different  strains  of   the  fungus  (plus  and  minus)  come  together  to  form  the  sexual  stage  (see  diagram).  

Detection and  Inspection   On  leaves,  a  rapid  development  of  red-­‐brown  and  yellow  streaks,  drying  from  the  margins   back  to  the  mid-­‐rib,  and  early  death  of  leaves,  are  typical  of  this  disease.  

Management CULTURAL  CONTROL   Carry  out  the  following   recommended  to  allow  more   air  into  the  plantation  to  dry   the  leaf  surface,  to  prevent   infection,  or  to  reduce  the   number  of  spores:   • Cut  off  leaves  (if  more   than  50%  infected),  or  cut   out  parts  of  leaves;   • Plant  at  wide  spacings;     • Weed  regularly;   • Cut  out  suckers,  leaving   3-­‐4  plants  of  different   sizes  per  plant;   • Remove  and  burn  old  infected  leaves;                                                                                                           • Use  a  mulch  to  improve  plant  health.    

RESISTANT VARIETIES   Many  plantains  in  Solomon  Islands  are  either  resistant  or  partly  resistant  to  Black  Sigatoka.   However,  if  farmers  want  to  grow  varieties  with  Cavendish  qualities  for  household  use  or  the   market,  then  they  should  ask  MAL.  The  Honduran  Foundation  of  Agricultural  Research  has   bred  varieties,  e.g.,  FHIA-­‐1;  FHIA-­‐2,  FHIA-­‐3.  These  are  dessert  or  dessert/cooking  bananas  with   resistance  to  Black  Sigatoka.      

CHEMICAL CONTROL   Fungicides  are  only  recommended  for  commercial  plantations,  these  are:     Protectant  fungicides:   • dithiocarbamates  (e.g.,  mancozeb);   • Banana  misting  oil.   Systemic  fungicides     • triazoles  (e.g,  propiconazole  and  flusilazole);     • strobilurins  (e.g.,  azoxystrobin).       It  is  important  to  rotate  the  fungicides  in  the  different  groups  to  prevent  the  build  up  of   resistant  strains  of  the  fungus.  In  drier  times,  mancozeb  can  be  used  alone.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Brown Root  Rot    

Extension Fact  Sheet  

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Common name:  Brown  root  rot   Scientific  name:  Phellinus  noxius.   Hosts:  The  fungus  has  a  wide  host  range,  attacking  native  forest  trees  and  plantation  crops,   including  cocoa,  oil  palm,  rubber,  coffee  and  Cordia  (especially  in  Vanuatu).    

Damage The  fungus  attacks  the  roots,  and   this  causes  the  leaves  to  yellow   and  wilt,  beginning  at  the  branch   tips.  Very  quickly,  all  the  leaves   fall.  The  fungus  forms  a  dark   brown  to  black  crust  on  the  trunk   with  a  white  margin,  often  with   clear  drops  of  liquid;  the  crust   grows  up  to  one  metre  (photo,   left).  It  grows  on  the  roots,  too,   and  often  soil  and  small  stones   can  be  seen  within  it.     Once  a  tree  is  infected,  there  is   no  way  to  cure  it:  it  will  die.  If  left   unattended,  the  fungus  will   spread  outwards  along  the  roots   to  healthy  trees  around;  infection   of  these  will  lead  to  their  death   and  further  spread,  so  that  in  a   short  time  a  large  number  of  trees  are  killed.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Biology and  Life  Cycle   Phellinus  lives  in  the  forest  where,  under  natural  conditions,  it  does  little  harm.  However,   when  the  trees  are  cleared  for  cocoa  or  a  plantation  of  timber  trees,  condition  becomes  ideal   for  its  spread.  In  the  new  plantation,  all  the  trees  are  alike  and  if  susceptible  to  Phellinus,   spread  is  rapid.       The  fungus  spreads  from  the  old  stumps,  left  when  the  forest  was  cleared.  These  become   infected  by  spores  or  more  likely  by  the  fungus  in  the  soil.  The  fungus  spreads  from  these  to   the  cocoa  by  root-­‐to-­‐root  contact.  Eventually,  it  reaches  the  base  of  the  tree  and  climbs  the   outside.  The  fungus  has  enzymes  to  extract  nutrients  from  dead  and  dying  roots  and  stems.   The  life  cycle  is  illustrated  above  (diagram1).     The  crust  is  sterile,  that  means  it  does  not  produce  spores.  However,  spores  are  produced  in   the  brackets.  These  are  dark  brown  above  with  red-­‐brown  margins  and  grey  underneath.  They   have  not  been  seen  on  cocoa  in  Solomon  Islands,  but  they  occur  on  rotten  stumps  of  many   forest  trees  (photo,  centre)  and  on  Leucaena  (photo,  right),  and  probably  on  other  shade  trees.  

Detection and  Inspection   Routine  inspection  of  the  base  of  the  trees  is  necessary  to  look  for  the  crust  that  grows  up  the   trunk.  Also,  look  for  brackets  of  the  fungus  on  old  stumps  of  forest  trees.  Also,  look  for  them   on  shade  trees,  e.g.,  Leucaena.    

Management CULTURAL  CONTROL   After  clearing  the  forest,  it  is  important  to  survey  for  stumps  that  have  brackets  of  Phellinus   growing  from  them.  These  should  be  removed  together,  if  possible,  with  all  roots  larger  than   2.5  cm  diameter.  The  surveys  need  to  be  done  on  a  regular  basis,  every  3  months  at  least.     If  diseased  cocoa  trees  are  seen,  remove  them  immediately,  taking  out  as  much  of  the  larger   roots  as  possible.  Also,  carefully  remove  the  soil  from  around  the  trees  nearby  and  inspect  for   the  crust  at  the  base  of  the  trunk  and  on  the  larger  roots.  If  seen,  remove  the  trees.    

CHEMICAL CONTROL   There  is  no  chemical  control  option  for  this  disease.      

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The  diagram  of  the  life  cycle  is  from  APSnet  Education  Center.    Brown  root  rot.    The  permission  of  The  American   Phytopathological  Society  to  use  this  diagram  is  gratefully  acknowledged.   http://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycetes/Pages/BrownRootRot.aspx  

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Butt &  Root  Rots  

Extension Fact  Sheet  

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Common name:  Butt  and  root  rots   Scientific  name:  Ganoderma  (photo,  left  &  right)  and  Trametes  (photo,  centre).  There  are   several  species  of  both  fungi.   Hosts:  Oranges  and  other  types  of  citrus  are  attacked.  These  fungi  have  a  wide  host  range   and  infect  many  forest  and  plantation  trees.  Ganoderma  is  a  major  problem  in  oil  palm.  

Damage   Damage  to  the  roots  and  trunks  of  oranges  and  other  citrus  by  butt/root  rot  fungi  prevents   the  movement  of  food  and  water.  Leaves  turn  yellow  and  fall,  fruit  production  ceases,  and   there  is  a  slow  dieback  of  the  branches.  Inside  the  trunk  a  white  rot  occurs.  Later,  either   when  the  tree  is  still  alive  or  when  it  is  dead,  the  brackets  appear  at  the  base  of  the  trunk   (the  butt).     It  is  not  known  how  many  months  or  years  pass  between  infection  of  an  orange  and   development  of  the  bracket.  The  first  sign  of  damage  is  usually  dieback  of  a  branch.  Slowly   other  branches  die,  until  the  whole  tree  is  dead;  this  can  take  several  years.    

Biology and  Life  Cycle   Ganoderma  and  Trametes  are  often  called  bracket  or  shelf  fungi,  because  of  the  shape  of   the  structure  that  grows  out  from  the  tree.  This  is  the  only  part  of  the  fungus  that  can   easily  be  seen:  the  rest  is  in  the  soil  or  inside  the  tree  causing  white  rots.  The  bracket  or   shelf  is  the  part  of  the  fungus  where  the  spores  or  seeds  are  produced;  the  spores  are   very  small,  too  small  to  be  seen  by  the  eye.       The  fungi  are  spread  by  spores  produced  by  the  brackets.  Many  millions  of  spores  are   produced  and  these  travel  long  distances  in  the  wind.  There  are  two  ways  that  infection   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   occurs:  either  the  spores  fall  to  the  soil,  germinate  and  grow  or  they  enter  through   wounds  in  the  tree.  Wounds  are  the  more  likely.  Fungal  threads  develop  and  these  grow   through  the  trunk.     Spread  of  the  fungi  in  the  soil  is  probably  through  root-­‐to-­‐root  contact.       Once  inside  the  tree,  the  fungi  follow  the  central  areas  where  water  and  food  flow   between  the  roots  and  the  leaves.  Brackets  develop  only  when  rots  are  extensive.  They   may  last  only  a  few  months  (Trametes)  or  a  long  time  (Ganoderma).  

Detection and  Inspection   If  branches  start  to  die  back,  then  it  is  possible  that  the  roots  have  been  infected  with   Ganoderma  or  Trametes.  There  is  no  way  to  be  sure  until  the  brackets  form.  However,  it   is  worthwhile  checking  the  base  of  any  old  dead  or  dying  trees  nearby  incase  these  have   brackets  growing  from  them.  

Management CULTURAL  CONTROL   Dig  out  infected  trees:  There  is  no  effective  treatment  for  Ganoderma  or  Trametes  once   the  bracket  appears.  It’s  a  sign  that  the  fungi  have  been  feeding  on  the  tree  for  some   time,  and  large  rots  are  already  present.  The  tree  should  be  removed.  Dig  it  out  along   with  all  the  main  roots.       Do  not  damage  healthy  trees:  Spores  of  the  fungus  can  enter  the  butt  through  wounds.   Do  not  damage  the  bark.  Stop  people  cutting  the  bark  with  bush  knives!      

CHEMICAL CONTROL   Chemical  control  is  not  an  option  for  these  diseases.  

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Chilli Viruses  

Extension Fact  Sheet  

5

Common name:  Chilli  viruses   Scientific  name:  Cucumber  mosaic  virus;  Tomato  mosaic  virus;  possibly  other  viruses.   Hosts:  Cucumber  mosaic  virus  has  a  very  wide  host  range,  including  cucurbits,  tomato,  banana,   tobacco  and  many  species  of  legumes  –  there  are  many  strains.  Tomato  mosaic  virus  also  has  a   wide  host  range:  other  than  tomato  it  infects  tobacco  and  numerous  weeds.  The  host  range  of   these  viruses  in  Solomon  Islands  is  not  well  known.    

           

Damage

Leaves show  yellow  spots  and  blotches,  curls  and  crinkles  when  infected  with  Cucumber   mosaic  virus.  Infections  with  Tomato  mosaic  virus  produce  a  general  yellowing  of  the  leaves.   However,  it  is  difficult  to  identify  these  viruses  by  symptoms  alone.     Usually,  symptoms  are  not  severe,  and  it  is  likely  that  yields  are  not  reduced  greatly.  Plants   continue  to  produce  acceptable  crops  of  fruits.  However,  some  plants  near  Auki,  Malaita,  have   shown  severe  symptoms  of  yellow,  distorted,  bunched  leaves,  and  fruit  production  on  these   plants  is  low  (photo).  It  is  not  known  what  viruses  are  present  in  these  plants1.  

Biology and  Life  Cycle   Cucumber  mosaic  virus  infects  a  wide  range  of  crops  and  weeds.  Aphids  (green  fly)  spread  the   virus  from  plant  to  plant.  The  aphid,  Aphis  gossypii,  is  common  in  Solomon  Islands  and  is   possibly  the  most  important  means  of  spread.  Aphids  spread  Cucumber  mosaic  virus  in  a  non-­‐ persistent  way;  this  means  that  they  pick  up  the  virus  when  feeding,  and  transfer  it   immediately  to  healthy  plants  on  their  mouthparts.     1

Dr  Denis  Persley,  Queensland  Department  of  Primary  Industries  &  Fisheries  suggests  that  the  symptoms  might  be  due  to  a   whitefly-­‐transmitted  geminivirus. AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Tomato  mosaic  virus  is  easily  spread  as  it  is  not  easily  destroyed  and  is  highly  infectious.  The   main  sources  of  infection  are:     • The  seed;  the  virus  contaminates  the  outside  of  the  seed;   • Old  crops  of  tomato  and  chilli;  these  serve  as  a  source  of  virus  for  new  crops;   • Undecomposed  plants  in  the  soil;   • People  handling  the  plants,  seedlings  in  particular;   • Other  crops  (e.g.,  tobacco),  and  weeds  (e.g.,  Cape  gooseberry,  Physalis  spp.).  

Detection and  Inspection   Look  for  yellow  and  green  patterns  on  the  leaves,  mild  distortions  and  curling.  It  is  not  possible   to  be  sure  which  virus  is  present  in  plants  with  these  symptoms;  sap  from  leaves  needs  to  be   sent  for  analysis  using  antisera  or  molecular  methods.    

Management CULTURAL  CONTROL   • •

For Cucumber  mosaic  virus,  do  not  plant  new  plots  of  chilli  next  to  old  ones;  they  will  act  as   a  source  of  the  virus.  Pull  out  and  burn  the  old  plants  before  planting  a  new  crop.     For  Tomato  mosaic  virus,  destroy  old  crops  as  soon  as  possible;  and  avoid  handling   seedlings,  especially  after  handling  older  plants.      

RESISTANT VARIETIES   Nothing  is  known  about  the  resistance  of  chilli  varieties  to  these  two  viruses.       CHEMICAL  CONTROL  

This is  not  an  option.  Insecticides  take  time  to  kill  insects;  by  the  time  the  aphids  are  dead,   they  have  already  fed  and  passed  on  the  virus.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Black Pod  &  Canker  

Extension Fact  Sheet  

6

Common name:  Black  pod   Scientific  name:  Phytophthora  palmivora.  It  is  NOT  a  fungus  but  a  water  mould,  related  to   algae.   Host:  The  water  mould  attacks  cocoa;  it  causes  Black  pod  and  canker.  Elsewhere,  it  causes   diseases  on  breadfruit,  coconut,  papaya,  and  many  other  crops.    

Damage Phytophthora  infects  pods  of  any  age,  from  the  time  they  are  small,  and  called  cherelles,  to   the  time  they  are  yellow  and  mature.  The  pods  are  at  first  brown  (photo,  3rd  from  left),  then   black  (photo,  left);  they  dry  but  stay  on  the  tree.  Pods  are  destroyed  in  10  days  or  less,   depending  on  size.  In  Solomon  Islands,  the  fungus  destroys  up  to  40%  of  the  pods.  The  number   destroyed  depends  on  rainfall,  variety  and  management  of  the  trees.       The  Water  mould  invades  the  trunk  and  branches  causing  cankers  (photo,  2nd  left).  This   happens  when  the  fungus  in  the  pods  or  in  the  flowers  grows  back  into  the  tree.  From  the   outside,  the  branch  initially  looks  healthy,  but  later  cracks  appear,  and  the  infected  area  may   be  slightly  sunken.  When  the  bark  is  removed  the  red  colour  of  the  canker  is  seen.  Trees  can   be  killed  by  canker  if  the  trunk  is  infected,  but  more  often  the  fungus  causes  branch  dieback.     The  fungus  also  infects  young  leaves  (photo,  right),  especially  the  leaves  of  water  shoots  or   chupons.  In  this  case,  the  damage  is  usually  minor.  

Biology and  Life  Cycle   The  fungus  needs  rain  to  complete  its  life  cycle.  Spores  are  produced  on  the  pods  and  spread   in  wind  and  rain  to  other  pods  nearby  or  to  new  plantations.  If  they  land  on  a  pod  or  young   leaf,  and  it  is  wet,  they  germinate.  There  are  two  ways:  a)  the  spores  germinate  like  a  seed  and   infect  the  pod  or  leaf;  or  b)  the  spores  produce  smaller  spores  which  burst  out  and  swim  short   distances  over  the  pod  or  leaf  surface,  then  they  germinate  and  infect.  In  both  cases,  the   Water  mould  kills  the  cells.  On  pods,  a  brown  circular  spot  is  produced,  which  expands  very   quickly.  On  young  leaves,  infections  often  start  at  the  leaf  tip  and  follow  the  veins,  which  turn   brown.  Infection  on  the  stems  of  water  shoots  causes  leaves  to  wilt.     White  areas  containing  the  spores  form  on  the  pods.  Spores  are  also  produced  on  the  leaves,   but  they  are  less  obvious.  Spores  on  pods  and  leaves  are  splashed  by  rain  to  those  all  around;   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   they  also  fall  to  the  ground  and  remain  in  the  soil  or  on  leaf  litter.  Heavy  rains  splash  the   spores  from  the  soil  up  to  1  m  above  ground,  infecting  pods  on  the  trunk  (photo,  3rd  left).   Apart  from  wind  and  rain,  spread  can  occur  in  other  ways:     • The  Water  mould  in  the  canker  grows  back  into  the  pod,  via  the  stalk;   • Ants  build  ‘tents’  of  soil  containing  spores  over  mealybug  colonies  on  the  pods;     • Flying  beetles  that  breed  in  the  pods  move  spores  to  healthy  pods;   • Rats  moving  through  the  plantation  transfer  the  Water  mould  by  chewing  first  on  infected   and  then  healthy  pods.  Possibly,  bats  do  the  same;   • On  pruning  tools  used  to  cut  off  pods  and  chupons.  

Detection and  Inspection   The  Water  mould  is  obvious  on  pods  as  brown  rapidly  growing  spots.  Cankers  are  less  obvious;   sometimes,  they  dry  out,  become  sunken  and  there  are  splits  between  dead  and  healthy   tissue.  There  may  be  a  red  liquid,  but  this  is  rare  on  Amelonado.     If  it  is  not  certain  that  Phytophthora  is  the  cause  of  a  black  pod,  take  a  piece  of  the  pod,  cut  a   hole  in  a  healthy  pod  and  place  it  in  the  hole.  Put  the  pod  in  a  plastic  bag.  Look  for  a  rapidly   growing  brown  rot,  and  a  white  area  at  the  margin.  

Management CULTURAL  CONTROL   Good  circulation  of  air  in  the  plantation  is  important  to  dry  pods  and  leaves  quickly  after  rain,   reducing  the  time  when  infection  can  occur.  Therefore:   • Use  a  light  shade  (about  600  trees  per  hectare  if  they  are  planted);   • Plant  cocoa  not  less  than  3  m  apart;   • Prune  to  create  an  open  canopy:  cut  out  branches  close  to  the  fork  (jorquette),  especially   those  forming  a  second  storey;  cut  out  branches  near  or  touching  the  ground;  remove   water  shoots.     Remove  diseased  pods  as  often  as  possible,  at  least  every  month,  preferably  more  often   during  the  main  crop  season.  Take  the  pods  from  the  plantation  and  bury  them.      

RESISTANT VARIETIES   Amelonado  is  more  resistant  than  other  varieties  tested  in  Solomon  Islands,  such  as  Na32  and   Trinitario.  Resistant,  high  yielding  varieties  have  been  bred  for  resistance  to  Black  pod  disease   in  Papua  New  Guinea.    

CHEMICAL CONTROL   Copper  sprays  are  useful,  if  applied  regularly  (every  2  weeks)  to  the  pods,  especially  during  the   main  crop  season.  Trunk  injections  using  phosphorous  acid  are  also  effective.  They  are  applied   with  a  purpose-­‐made  syringe,  once  or  twice  a  year,  depending  if  there  is  low  or  high  disease.   See  MAL  extension  staff  for  advice.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Gummy Stem  Blight  

Extension Fact  Sheet  

7

Common  name:  Gummy  stem  blight   Scientific  name:  Didymella  bryoniae.   Host:  Watermelon  (Citrullus  lanatus),  cantaloupe  melon  (Cucumis  melo)  and  cucumber   (Cucumis  sativus).  

Damage The  spots  enlarge  rapidly  and  the  leaves  blacken,  shrivel  and  die  (photo,  left).  It  happens  so   quickly  that  it  is  called  ‘blight’.  The  loss  of  leaves,  and  the  damage  to  the  vines,  means  that  the   fruits  are  starved  of  food,  and  do  not  develop  properly.       If  the  disease  is  not  controlled  when  first  seen,  it  spreads  very  quickly,  especially  during  days  of   heavy  and  continuous  rain.  It  is  common  for  whole  crops  to  be  ruined  by  Gummy  stem  blight.  

Biology and  Life  Cycle   The  fungus  produces  small,  black,  round  structures,  like  baskets,  inside  leaf  spots;  the  baskets   can  just  be  seen  with  the  naked  eye;  they  are  clearer  with  a  hand  lens.  There  are  millions  of   tiny  spores  inside  these  baskets.     When  they  are  ready,  and  when  it  rains,  the  baskets  burst  open  and  the  spores  come  out.   Wind  and  rain  carry  the  spores  to  other  leaves.  When  the  spores  land  on  watermelon  leaves,   they  germinate  like  a  seed.  The  fungus  enters  the  leaf  and  grows  inside.  As  it  grows,  it  kills  the   leaf,  forming  the  round,  brown  spots.  The  spots  grow  and  join  together.  Then  more  baskets  of   spores  develop,  and  the  cycle  starts  again.    

Detection and  Inspection   In  the  nursery,  look  for  large  brown  spots  on  the  leaves  (photo,  right).  In  the  field,  look  for  the   rapid  development  of  black  spots  and  blotches,  that  are  typical  of  this  disease,  especially   during  wet  weather.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Note,  farmers  sometimes  mistake  the  disease  for  damage  caused  by  the  caterpillar  of  a   moth,  Diaphania  indica.  These  roll  the  leaves  with  silk  threads  and  eat  the  parts  between   the  veins.  (See  Diaphania  Watermelon  worm  Fact  Sheet  No.  33).  

Management CULTURAL  CONTROL   Carefully  choose  the  soil  and  site  for  the  nursery:     • Take  soil  only  from  areas  where  watermelon  has  not  been  grown  before;   • Make  the  nursery  far  away  from  watermelon  gardens;   • DO  NOT  make  the  nursery  downwind  from  watermelon  gardens  (otherwise  the  wind  and   rain  will  blow  spores  onto  the  nursery).     In  the  nursery  do  the  following:   • Check  for  leaf  spots,  at  least  every  2  days.  If  spots  are  present,  remove  the  plants  and  burn   them;     • If  there  are  many  spots,  do  not  use  any  of  the  seedlings;  throw  them  away  and  start  again.   Sterilise  the  soil  and/or  spray  the  next  lot  of  seedlings  with  a  fungicide;   • Sterilise  the  soil  by  heating  it  for  one  hour,  either  (a)  in  a  half  44-­‐gallon  drum  over  a  fire,  or   (b)  in  an  earth  oven  over  hot  stones.       Do  not  plant  watermelons  in  the  same  land  as  the  last  crop.  Leave  a  break  of  3  years.  The   fungus  can  survive  in  the  soil,  living  on  plant  remains.  After  harvest,  collect  and  burn  the  vines.     Rotate  with  sweet  potato,  cassava,  taro,  but  NOT  with  crops  in  the  watermelon  family,  such  as   cucumber,  pumpkin  and  melon.  Do  not  plant  watermelon  next  to  older  crops  that  already   have  Gummy  stem  blight.    

CHEMICAL CONTROL   Use  one  of  the  following  fungicides:  Bravo  (chlorothalonil),  Dithane  M-­‐45  (mancozeb)  or   copper  oxychloride.  Spray  every  7-­‐10  days.  See  the  leaflet:  Gummy  stem  blight  published  by   MAL.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Lesion Nematode    

Extension Fact  Sheet  

8

Common names:  Rough  skin,  Storage  rot,  Brown  dry  rot   Scientific  name:  Pratylenchus  coffeae.   Hosts:  In  Solomon  Islands,  lesion  nematodes  cause  a  disease  on  yam  (Dioscorea  alata)  and,   possibly,  banana  (Musa  species).  Note;  the  burrowing  nematode,  Radopholus  similis,  also   causes  a  disease  on  banana  that  looks  very  similar.    

Damage On  yam:  damage  to  roots  prevents  the  plant  from  taking  up  water  and  nutrients.  When  roots   are  damaged,  plants  become  stunted  and/or  die  early.  Often,  symptoms  of  the  disease  are  not   seen  until  the  yams  are  harvested  because:  (a)  in  many  yam  gardens  the  foliage  of  different   plants  is  mixed  together,  making  it  difficult  to  see  individual  plants;  and  (b)  damage  done  by   nematodes  often  comes  late,  so  symptoms  of  poor  growth  can  be  mistaken  for  early  maturity.     Damage  to  the  tubers  does  not  stop  at  harvest.  The  nematodes  continue  to  multiply  during   storage,  and  the  dry  rot  areas  spread  (photo,  top  left).  Often,  other  organisms  help  with  the   decay.  Decay  of  the  outer  areas  of  the  tubers  means  a  loss  of  planting  material.     On  banana:  Spots  appear  due  to  the  nematodes  feeding  and  breeding  inside  the  roots;  later   the  spots  join  together  forming  characteristic  red  and/or  black  patches  –  best  seen  when  roots   are  split  (photo,  top  right).  The  roots  die  and  the  outer  parts  rot.  The  result  is  a  weak,  stunted   root  system;  plant  growth  is  slow,  fruiting  is  poor  and  plants  readily  fall  over  in  the  wind.    

Biology and  Life  Cycle   Like  all  nematodes,  Pratylenchus  has  six  life  stages:  egg,  juvenile  (4)  and  adult  (See  diagram   below).  The  nematodes  lay  eggs  in  the  root,  or  in  soil  close  by.  Eggs  hatch  in  a  few  days  and   the  young  nematodes,  called  juveniles  or  larvae,  moult  several  times  before  they  become     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   adult.  The  larvae  as  well  as  the  adults  enter  the  roots;  they  force  their  way  between  or  through   the  cells.  Pratylenchus  has  a  stylet  or  spear  (photo,  left  below  arrowed)  in  its  mouth,  and  it   uses  this  to  penetrate  the  roots  and  to  feed  on  the  cells.       The  life  cycle  is  2-­‐3  weeks,  depending  on  moisture  and  temperature.  When  the  cells  die,  the   nematodes  migrate  through  the  root  (photo,  lower  right)  or  tuber  in  search  of  healthier  parts,   or  they  return  to  the  soil  and  search  for  another  root.  The  nematodes  spread  short  distances  in   soil  water.  They  are  spread  long  distances  on  yam  setts  and  banana  suckers.     Young  and  adult  nematodes  feed  on  roots  of  weeds  during  fallow  periods,  and  on  the  roots  of   other  crops  between  crops  of  yam  and  banana.  They  also  remain  alive  in  stored  yam  tubers  or   in  the  banana  corms.  When  infected  yam  tuber  pieces  or  banana  suckers  are  planted,  the   nematodes  emerge  and  move  through  the  soil  until  they  find  young  roots  to  infect.  

Detection and  Inspection   Look  for  signs  of  dry  rot  on  yam  tubers   at  harvest,  and  in  storage.  Look  for   bananas  that  have  blown  over,  and  roots   with  red  and/or  black  patches.  

Management CULTURAL  CONTROL   •

Leave at  least  3  years  between  crops   of  yam  grown  on  the  same  land.  If   possible,  allow  the  land  to  fallow   naturally  or  plant  marigolds  or  cover   crops,  e.g.,  green  panic  (Panicum   maximum),  siratro  (Macroptilium   atropurpureum)  and  velvet  bean,   Mucuna  sp.;   Use  local  knowledge,  and  plant   where  crops  have  grown  well   before;   DO  NOT  store  tubers  with  signs  of   dry  rot.  Regularly  inspect  tubers  in   storage;  remove  those  with  Brown  dry  rot;   Inspect  yam  cuttings  and  banana  suckers  before  planting.  On  yams,  select  and  cut  healthy   yams  first.  Cut  diseased  yams  and  remove  any  dry  rot.  Wipe  knife  with  bleach  between   cutting  each  tuber.  On  banana,  cut  off  roots  and  cut  out  any  rots  on  the  corms.   There  is  no  information  on  resistant  varieties.  

HOT WATER  TREATMENT   Hot  water  treatment  of  yam  tubers  and  banana  suckers  is  an  effective  method  of  killing   nematodes.  It  has  to  be  done  carefully.  The  temperature  of  the  water  and  the  time  of  dipping   must  be  controlled.  It  is  51°C  for  10  minutes  for  yam  and  53°C  for  20  minutes  for  banana.  Seek   assistance  from  MAL  before  carrying  out  hot  water  treatment.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Mango Flower  Blight    

Extension Fact  Sheet  

9

Common name:  Mango  flower  blight   Scientific  name:  Glomerella  cingulata  (it  also  has  the  name  of  Colletotrichum  gloeosporioides).   Glomerella  is  the  sexual  stage  of  the  fungus.  The  disease  is  often  referred  to  as  Anthracnose  of   mango.  Another  fungus  also  causes  leaf  spots:  Stigmina  mangiferae  (see  below).   Host:  Mango.  Many  other  crops  are  hosts  of  this  fungus,  including  avocado,  coffee,  eggplant,   papaya,  sweet  pepper,  tomato  and  yam.  There  are  different  strains,  infecting  different  hosts.  

Damage The  fungus  causes  severe  damage  during  wet  weather.  It  causes  flower  blight,  leaf  spots   (photo,  left),  young  shoot  blight  and  fruit  rot.  In  wet  weather,  flower  blight  results  in  low  yield   and  shoot  dieback.  Young  infected  fruits  develop  black  spots,  shrivel  and  fall  off.  Infection  of   mature  fruit  leads  to  losses  in  storage  (photo,  right).  

Biology and  Life  Cycle   Masses  of  spores  occur  in  tiny  dish-­‐like  structures  in  the  spots;  they  are  splashed  by  rain  onto   other  leaves,  flowers  and  shoots.  They  germinate,  like  a  seed,  infect  and  produce  more  spots   and  blights.  Young  leaves  are  most  susceptible  to  infection.       At  first,  the  spots  are  small,  black  and  irregular,  often  expanding  to  form  large  dead  areas  that   dry  and  fall  out.  On  mature  fruits,  the  fungus  remains  as  pinpoint  infections  until  the  fruit   ripens;  then  the  infections  form  dark  brown  to  black  spots  with  pink  spore  masses.    

Detection and  Inspection   Look  for  flower  blights,  and  spots  on  young  leaves  and  fruits  in  wet  weather.  However,  it  is  not   always  easy  to  distinguish  between  diseases  caused  by  Glomerella  and  Stigmina.  Spots  of   Glomerella  are  usually  larger  on  the  leaves,  whereas  those  of  Stigmina  are  about  6  mm   diameter,  surrounded  by  a  wide  greenish  zone.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Stigmina  causes  black  spots  on  the  leaves,  which  may  merge  to  form  large  black  areas.  During   wet  weather  the  fungus  can  cause  early  leaf  fall  (photos,  below).    

Management Under  local  conditions,  there  is  little  that  can  be  done  to  prevent  infection  from  these   pathogens.  Control  requires  trees  to  be  pruned  and  sprayed  with  fungicide.    

CULTURAL CONTROL   It  is  important  to  prune  trees  to  allow  air  to  flow  freely  through  the  tree  canopy  to  reduce   humidity.  Trees  should  be  less  than  4  m  tall  for  easy  management  and  harvesting.  Diseased   twigs  should  be  removed  and  burnt  along  with  fallen  leaves.      

RESISTANT VARIETIES   Indo-­‐Chinese/Philippine  varieties  are  said  to  have  some  resistance  to  the  fungus  and  need  to   be  tested  in  Solomon  Islands.  They  have  good  flavour,  and  flesh  with  low-­‐fibre.  See  MAL  for   information.    

CHEMICAL CONTROL   Frequent  and  timely  application  of  chemicals  (e.g.,  copper  oxychloride  or  mancozeb)  is   necessary  to  control  Glomerella  leaf  and  flower  blight.  Applications  need  to  begin  when  the   flowers  first  appear  and  continue  at  recommended  intervals  until  the  pre-­‐harvest  waiting   period.       Post-­‐harvest  dips  in  fungicide  (carbendazim)/hot  water  (5  minutes  at  52°C)  control  fruit   infections,  preventing  storage  rots.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Mitimiti Corm  Rot  

Extension Fact  Sheet  

10

Common name:  Mitimiti  disease,  Mitimiti  corm  rot   Scientific  name:  Hirschmanniella  miticausa.  It  is  only  known  from  Solomon  Islands.   Host:  Colocasia  taro.  It  is  not  known  from  any  other  crop.  

Damage The  nematode  causes  a  corm  rot.  Corms  show  irregular  zones  of  dry,  brown  rot,  1-­‐10  mm   wide,  developing  from  the  base.  At  first,   the  lines  of  rot  follow  the  water  and   food  transport  systems  inside  the  corm.   Healthy  tissue  alongside  the  rots  is  red   and  corms  look  similar  to  uncooked   fatty  meat  (hence  the  name  ‘mitimiti’  in   Solomon  Islands).  Often,  the  bottom   part  of  the  corms  is  completely  decayed   by  secondary,  brown  soft  rots  (photo,   right).     The  nematode  reduces  plant  growth   and  corm  size.  However,  dryland  taro   often  fail  to  show  signs  of  the  disease   until  harvest.  In  Rennell  and  Ontong  Java,  where  taro  are  grown  in  swamps,  cultivation  has   been  abandoned,  as  damage  is  severe  (photo,  left).  

Biology and  Life  Cycle   There  is  little  known  about  the  biology  of  this  nematode:  it  has   not  been  studied.  However,  the  life  cycle  is  probably  typical  of   other  migratory  nematodes,  with  eggs,  juveniles  (4)  and  adults   (photo,  right)  of  both  sexes  (see  diagram).  The  eggs  are  laid  in  the   soil  or  in  the  roots,  and  juveniles  or  adults  move  in  and  out  of  the   roots.  In  this  way,  it  is  similar  to  the  lesion  nematode,  Pratylenchus.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   It  is  likely  that  in  dryland  situations,  nematodes  move  short  distance  by  swimming  in  films  of   water  around  soil  particles  or  are  moved  greater  distances  in  ground  water.  In  swamps,  the   nematode  spreads  by  swimming  and  in  water  currents.  

Spread to  new  areas  is  on  infected  planting  material,  either  in  roots  and  corm  pieces  or  in   contaminated  soil.  How  long  the  nematode  can  survive  in  the  soil  after  plants  have  been   harvested  is  not  known.    

Detection and  Inspection   Look  for  the  reddening  of  corms  and  brown,  dry  rots  at  the  base  of  the  plant.  Nematodes  need   to  be  extracted  from  corms  and  roots  for  confirmation.  Note,  that  this  disease  has  only  been   found  in  Choiseul,  Kolombangara,  Ontong  Java  and  Rennell.  

Management QUARANTINE   The  spread  of  mitimiti  disease  from  one  island  to  another  should  be  prevented  by  local   quarantines.      

CULTURAL CONTROL   The  most  effective  and  practical  control  measure  is  to  ‘clean’  the  planting  material  free  from   nematodes.  Remove  the  outer  leaves  and  trim  the  corm  back  to  white  healthy  tissue,  leaving  a   few  centimeters  without  roots;  this  will  ensure  freedom  from  nematodes.  It  is  best  to  avoid   planting  suckers  with  corms  attached  as  it  increases  the  risk  of  spreading  the  nematode,  as  is  it   not  possible  to  see  if  rots  are  present.         On  hillsides,  avoid  planting  down  the  slope  from  gardens  where  Hirschmanniella  was  present   before,  as  nematodes  may  be  carried  in  soil  or  run-­‐off  water.    

RESISTANT VARIETIES   There  is  no  information  on  resistance  of  varieties,  except  that  a  semi-­‐wild  variety  known  as   Tiko  on  Malaita  had  resistance  when  planted  on  Ontong  Java.  This  variety  was  crossed  with   variety  Luhu  from  Guadalcanal.  Other  Solomon  Islands  varieties  were  crossed  with  a  wild   variety  from  Bangkok.  The  result  of  planting  these  seedlings  on  Ontong  Java  is  unknown.    

HOT WATER  TREATMENT   •

• •

Hot water  treatment  of  planting  material  has  been  suggested  for  the  control  of   Hirschmanniella.  Hot  water  treatment  of  ‘tops’  at  50°C  for  less  than  30  minutes  did  not   damage  them,  but  at  55°C  for  15  and  30  min  some  were  killed;   If  it  is  done,  there  is  a  need  to  carefully  measure  the  temperature  and  time.  Also,  the  ‘tops’   must  have  more  and  1  cm  of  corm  tissue;   DO  NOT  use  the  method  except  on  small  numbers  of  taro  to  establish  a  source  of   nematode-­‐free  planting  material.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Athelia Wilt    

Extension Fact  Sheet  

11

Common names:  Wilt,  Southern  blight,  Athelia  wilt   Scientific  name:  Athelia  rolfsii,  the  sexual  state  of  the  fungus.  It  is  also  known  by  the  asexual   state,  Sclerotium  rolfsii.  The  sexual  stage  (see  secondary  cycle,  below)  is  not  often  seen.     Hosts:  The  fungus  has  a  wide  host  range.  In  Solomon  Islands,  it  is  common  on  carrot,  beans,   cucurbits,  sweet  pepper,  peanut  (photo,  right),  sweet  potato  (photo,  left),  taro  and  tomato.    

Damage  

The fungus  is  soil  borne.  It  usually  infects  the  lower  stem  near  the  soil  surface.  On  peanut,  the   first  sign  of  the  disease  is  a  wilt  of  a  single  leaf  and  soon  after  the  wilt  of  the  entire  plant.   During  warm  wet  weather,  the  fungus  spreads  from  plant  to  plant.  

Biology and  Life  Cycle   When  the  cotton  wool-­‐like  growth  of  the  fungus  comes  into  contact  with  susceptible  roots,   leaves  or  stems,  direct  penetration  occurs,  but  it  can  also  penetrate  through  wounds.  The   fungus  produces  chemicals  that  produce  soft  rots  in  2-­‐4  days  after  infection.  When  the  soft   rots  girdle  the  stem,  the  foliage  wilts  and  plant  death  follows  soon  after.  The  fungal  growth   can  easily  be  seen  with  the  naked  eye.       About  7  days  after  infection,  the  cotton  wool-­‐like  growth  begins  to  form  sclerotia.  These  are   0.5-­‐2  mm  diameter  and  made  up  of  tightly  packed  bundles  of  the  fungus.  They  are  white  and   then  light  brown  as  they  mature.  Sclerotia  are  the  resting  stage  of  the  fungus,  keeping  it  alive   when  there  are  no  plants  to  infect.  Sclerotia  may  remain  alive  for  several  years  in  soil,  potting   media,  or  in  plant  debris.  Other  than  sclerotia,  the  fungus  can  survive  between  crops  in  the   remains  of  plants.  The  life  cycle  of  A  rolfsii  is  given  below  (see  diagram1).     1 The diagram of the life cycle is from APSnet Education Center. Southern blight. The permission of The American Phytopathological Society to use this diagram is gratefully acknowledged. http://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycetes/Pages/SouthernBlight.aspx

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Spread  over  short  distances  is  by  the  cotton  wool-­‐like  growth;  spread  over  long  distances  is  by   movement  of  infected  plant  material  or  infested  soil.  The  wind  can  carry  soil  containing  the   sclerotia.  

Detection and  Inspection   The  presence  of  the  thick   white  cotton  wool-­‐like   growth  at  soil  level  and   the  presence  of  sclerotia   are  very  typical  of  this   fungus.  Look  for  plants   that  have  wilted   suddenly.  

Management CULTURAL  CONTROL   The  fungus  has  such  a   large  number  of  hosts   that  crop  rotation  is  not  a   practical  solution.   However,  bananas  appear   resistant  to  infection  and   maize  and  cabbages  are   little  affected.  The  following  measures  are  important:   • Avoid  land  where  there  is  a  previous  history  of  this  disease;   • After  harvest,  remove  plant  remains  and  burn  them;   • Where  possible,  plough  the  land  deeply:  sclerotia  do  not  survive  for  more  than  45  days  if   buried  20-­‐30  cm;   • Check  that  plants  taken  from  a  nursery  are  free  of  the  fungus;   • Remove  infected  plants  with  soil  around  the  roots  as  soon  as  they  start  to  wilt,  taking  care   not  to  spread  the  fungus  by  dropping  soil/sclerotia  onto  other  plants;   • Remove  wilted  sweet  potato  plants  and  replace  with  cassava.          

RESISTANT VARIETIES   Little  success  has  been  reported  in  finding  varieties  -­‐  of  the  crops  that  are  susceptible  -­‐  with   resistance  to  this  fungus.    

CHEMICAL CONTROL   Many  fungicides  have  been  recommended  for  the  control  of  A.  rolfsii,  but  they  are  either  not   available  and/or  too  expensive  for  use  in  Solomon  Islands.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Pink Disease    

Extension Fact  Sheet  

12

Common name:  Pink  disease   Scientific  name:  Phanerochaete  salmonicolor  (also  known  as  Corticium  salmonicolor).   Host:  Cocoa  is  a  major  host,  but  it  occurs  on  Agathis  (kauri),  Citrus,  Cordia  and  Hibiscus.    

Damage Branch  dieback  occurs  (photo,  left),  and  occasionally  death  of  the  tree  when  infections  occur   at  the  fork  or  jorquette  (photo,  right).  Often,  patches  of  infected  trees  are  seen  as  the  disease   spreads.  If  management  is  poor,  and  weather  conditions  encourage  the  disease,  losses  can  be   high,  but  usually  the  disease  is  of  minor  importance.  Trees  between  2  and  6  years  are  said  to   be  more  severely  affected.  

Biology and  Life  Cycle   Spores  of  the  fungus  are  spread  by  wind  and  rain.  They  need  water  to  germinate;  they  can   infect  through  healthy  bark.  The  first  sign  of  the  disease  is  white  threads  of  the  fungus  over  the   bark;  they  look  like  cobwebs.  White  pustules  appear  through  cracks  and  through  the  natural   openings  in  the  bark.  Later,  a  pink  crust  develops  which  produces  spores.  Later  still,  but  only   occasionally,  the  colour  fades  and  orange-­‐red  pustules,  which  contain  another  type  of  spore,   are  seen.  At  this  stage,  the  bark  is  often  sunken,  split  and  gum  is  present;  these  areas  are   called  cankers.  The  leaves  on  the  infected  branches  die,  but  remain  attached.       When  it  is  too  dry  and  unfavourable  for  growth,  the  fungus  remains  alive  in  the  branch  and   trunk  cankers.  

Detection and  Inspection   Look  for  the  pink  crust  on  the  stems  and  trunk.  The  fungus  is  often  seen  on  the  main  fork  or   jorquette.  Regular  surveys  to  detect  infections  are  very  important.  Often  the  first  sign  of  the   disease  is  the  sudden  death  of  a  branch,  with  the  brown  leaves  remaining  attached.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management CULTURAL  CONTROL   •

Prune out  the  infected  branches  as  soon  as  the  fungus  is  seen.  If  the  fungus  has  infected   the  fork  or  jorquette,  then  consider  a  chemical  treatment,  otherwise  the  tree  will  have  to   be  cut  down  and  allowed  to  regrow  from  the  stump.  It  is  important  to  prune  during  dry   weather.  The  pruned  branches  should  not  be  left  in  the  plantation,  but  taken  out  and   burnt.  Always  prune  at  least  30  cm  below  any  sign  of  the  fungus;   The  health  of  the  trees  may  be  important  in  preventing  outbreaks  of  this  disease.  If  trees   are  stressed,  because  they  are  too  close  or  growing  in  soils  with  poor  nutrition,  then  they   may  be  more  susceptible;   Shade  is  another  important  factor:  heavy  shade  creates  conditions  of  high  humidity,  which   is  ideal  for  infection  and  spore  production.  Therefore,  make  sure  shade  is  properly   controlled.  

CHEMICAL CONTROL   Copper  fungicides  are  useful  if  applied  as  a  paste.  Prune  the  branches  and  apply  the  paste  to   the  cut  ends  and  along  the  remaining  parts.  Apply  to  infections  at  the  fork  or  jorquette.    

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sweetpotato Scab    

Extension Fact  Sheet  

13

Common name:  Sweetpotato  scab   Scientific  name:  Elsinoe  batatas,  but  sometimes  known  as  Sphaceloma  batatas  (the  asexual   stage).   Hosts:  It  is  only  known  from  sweet  potato.    

Damage   Young  leaves  are  infected  along  the  veins,  and  infections  also  occur  on  the  leaf  stalks  and   stems.  As  the  leaves  grow,  the  damage  to  the  veins  presents  proper  expansion,  and  they  twist,   curl  and  tear.  On  older  leaves,  infections  produce  pinpoint  spots  between  the  veins.  In  severe   cases  (rarely  seen  in  Solomon  Islands),  shoot-­‐tips  are  killed.       Varieties  differ  in  the  amount  of  damage  that  occurs.  The  disease  has  been  severe  in  Fiji  and   Tonga.  In  Tonga,  there  were  epidemics  of  the  disease  in  the  1980s  when  farmers  stopped   growing  most  varieties.  Damage  to  the  young  shoots  can  slow  early  growth  and  result  in   reduced  yields.  In  Papua  New  Guinea  highlands,  comparisons  between  healthy  and  diseased   plants,  showed  a  60%  difference  in  yield  of  storage  roots.  Most  varieties  in  Solomon  Islands   are  resistant  to  the  fungus,  and  yields  are  not  likely  to  be  affected.    

Biology and  Life  Cycle     The  fungus  is  taken  to  new  gardens  on  planting  material.  As  the  cuttings  grow,  the  fungus   produces  very  small  spores  in  the  scabby  areas.  These  spores  are  spread  by  rain-­‐splash  from   plant  to  plant.  They  germinate,  like  seeds,  in  water  on  the  surface  of  the  leaf  and  stem,   penetrate  and  cause  the  spots  and  scabby  lesions.  Soon  after  infection,  more  spores  are   produced.       It  is  possible  that  the  fungus  survives  in  crop  debris,  but  this  is  not  important  unless  crops  are   planted  one  after  the  other.  Most  spread  is  from  planting  infected  vines.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection     Look  for  the  brown  scabby  marks  on  the  leaf  veins,  stalks  and  stems.  Look  for  torn,  cup-­‐shaped   leaves  and  twisted  stems.    

Management  

CULTURAL CONTROL   There  is  probably  little  that  farmers  can  do  to  control  this  disease  using  cultural  methods.  If   the  disease  is  severe  in  the  crop,  it  might  be  better  not  to  replant  on  the  same  land,  but  it  is   doubtful  that  it  will  make  any  difference.  This  is  because  the  disease  is  spread  from  crop  to   crop  in  already  infected  planting  material,  and  also  from  spores  in  wind-­‐driven  rain.       If  growers  really  want  to  grow  susceptible  varieties,  because  of  their  taste  and  high  market   demand,  for  instance,  then  they  should  do  the  following.  It  is  very  important  that  they  start   the  crop  with  disease-­‐free  planting  material.       • Make  a  nursery  –  raised  beds,  shaded  by  coconut  leaves  –  and  plant  washed  sweet  potato   roots,  leaving  a  small  gap  of  1-­‐2  cm  between  each;   • Cut  vines  30  cm  vines  long  when  the  roots  sprout,  checking  each  one  to  ensure  that  scab  is   not  present;   • Plant  vines  in  new  gardens,  where  sweet  potato  has  not  been  grown  for  1-­‐2  years.     Vigorous  early  growth  will  reduce  the  impact  of  the  disease  when  the  plants  become  infected   later.    

RESISTANT VARIETIES   This  is  the  most  important  method  of  control.  Varieties  differ  in  their  susceptibility  to  the   disease.  Some  are  very  resistant.  These  should  be  selected  and  grown  in  preference.  It  is  for   this  reason  that  scab  is  not  usually  a  problem  in  Solomon  Islands.  Farmers  avoid  those  varieties   that  show  severe  symptoms.      

CHEMICAL CONTROL   Fungicides  have  been  used  to  control  the  disease  in  Tonga  and  Papua  New  Guinea,  but  mostly   by  scientists.  They  could  be  used  by  commercial  farmers,  for  instance,  by  those  who  want  to   grow  a  susceptible  variety  for  the  market.  The  recommendation  is  to:     • Dip  the  cuttings  for  15  min  in  mancozeb  before  planting;   • Spay  with  mancozeb  at  the  first  appearance  of  symptoms;   • Repeat  spraying  at  14-­‐  day  intervals,  until  1-­‐2  months  before  harvest,  depending  on  the   weather.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Taro Leaf  Blight    

Extension Fact  Sheet  

14

Common name:  Taro  leaf  blight   Scientific  name:  Phytophthora  colocasiae.  It  is  NOT  a  fungus  but  a  Water  mould,  related  to   algae.   Hosts:  The  fungus  attacks  taro  and  edu  (vili,  nepa;  Alocasia);  these  are  the  only  two  hosts   known  from  the  Pacific  islands.    

Damage  

Taro leaf  blight  reduces  the  life  of  the  leaves:  instead  of  lasting  40  days  they  last  20.  The  result   is  that  plants  have  few  leaves  and  small  corms.  Yield  is  reduced  by  about  40%.     Taro  leaf  blight  also  causes  a  firm,  brown  corm  rot  after  harvest.  It  takes  7-­‐10  days,  before  the   corm  is  completely  decayed;  often  other  fungi  are  present  in  the  rots.    

Biology and  Life  Cycle   The  Water  mould  is  active  in  wet  weather.  Spores  are  produced  on  the  leaves  and  spread  in   wind  and  rain  to  leaves  of  other  plants  nearby  or  to  those  in  distant  gardens.  If  they  land  on  a   leaf,  and  it  is  wet,  the  infect  it.  This  happens  in  two  ways:     • The  spores  germinate,  like  a  seed,  and  infect  the  leaf;  or     • The  spores  produce  smaller  spores,  which  burst  out  and  swim  short  distances  over  the  leaf   before  they  germinate  and  infect.       In  both  cases,  the  Water  mould  kills  the  cells  of  the  leaf  and  brown  spots  appear.  The  spots   grow  very  fast.  They  have  yellow  margins,  and  red-­‐brown  droplets  develop  on  the  under   surface.  The  droplets  dry  as  dark  pellets  (photo,  above  right).  Infection  occurs  anywhere  on   the  leaf  surface,  but  often  at  the  edges  where  rain  and  dew  collect.       After  a  few  days,  a  white  ring  can  be  seen  at  the  margin  of  the  spot  (photo,  next  page);  this  is   the  area  where  spores  are  produced.  There  are  millions  of  them.  However,  the  spores  dry  out   quickly  in  the  sun  and  by  mid-­‐morning  they  have  shrivelled  and  died.  They  only  stay  alive  if  it  is   cloudy  or  raining.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Apart  from  wind  and  rain,  spread  can  occur  in  other  ways:  (a)  on  suckers  planted  with  infected   leaves  attached;  (b)  on  stalks  of  planting  material  –  probably  on  the  cut  ends  in  wet  weather   when  stalks  are  trimmed  for  planting.       Corms  become  infected  only  after  harvest,  when  the  suckers  are  removed.    

Detection and  Inspection   Look  for  spots  that  grow  rapidly  (photo,  above  left),  and  leaves  that   die  early  -­‐  plants  have  3-­‐4  leaves  instead  of  6  -­‐7.  Look  for  secondary   spots  produced  below  the  first  ones.  White  rings  of  spores  border   the  spots,  seen  most  clearly  in  the  early  morning.  Look  for  dark,   irregular-­‐  shaped  pellets  on  the  underside  of  the  spots.  

Management Where  rainfall  is  high,  taro  leaf  blight  is  difficult  to  control.  Cultural   methods  can  be  tried,  but  they  are  often  not  effective.    

CULTURAL CONTROL   • • • •

Make new  gardens  as  far  away  as  possible  from  old  ones;   Inspect  young  taro  twice  a  week;  cut  off  infected  leaves  as  soon  as  they  are  seen.  Do  this   often,  but  it  can  only  delay  the  disease  in  places  where  rainfall  is  high;     Plant  suckers  without  leaves  attached;   Trim  taro  leaves  when  the  ‘tops’  are  dry  to  prevent  spores  infecting  the  cut  ends  of  the   stalks.  

Apart  from  the  above,  the  best  cultural  practice  is  to  make  gardens  in  the  highlands.  The   disease  is  much  less  at  cooler  temperatures.    

RESISTANT VARIETIES   Breeding  programs  in  Papua  New  Guinea  and  Samoa  have  produced  plants  resistant  to  taro   leaf  blight.  Some  of  these  are  available  from  MAL.  In  Solomon  Islands,  a  hybrid,  LA16,  has  been   found  to  be  resistant  to  taro  leaf  blight.      

CHEMICAL CONTROL   • •

Use copper  fungicides  (especially  copper  oxychloride),  but  they  have  to  be  used  often  and   are  only  recommended  where  taro  are  grown  for  sale;   Use  metalaxyl  (a  systemic  product)  in  combination  with  copper;  it  gives  even  better   control,  but  costs  are  high;   Use  phosphoric  acid  alternating  with  mancozeb  (used  successfully  in  Samoa).  

• To  prevent  storage  rots,  wash  the  soil  off  the  corms,  trim  the  leaves  and  put  them  in  plastic   bags.  Washing  the  corms  in  1  per  cent  household  bleach  beforehand  improves  storage.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

White Thread  on  Cocoa    

Extension Fact  Sheet  

15

Common  name:  White  thread   Scientific  name:  Marasmiellus  (Marasmius)  scandens.   Host:  Cocoa  is  the  major  host,  but  it  also  occurs  on  mango.  

Damage M  scandens  is  a  fungus.  The  disease  that  it  causes,  white  thread,  is  associated  with  poor  tree   maintenance.  If  management  is  poor,  large  number  of  leaves  can  be  destroyed,  but  the  impact   on  yield  has  not  been  recorded.  Normally,  the  disease  is  of  little  economic  importance.  

Biology and  Life  Cycle   The  life  cycle  of  this  fungus  has  not  been  fully  described.  The  white  threads  are  a  collection  of   strands  of  the  fungus,  and  these  grow  over  branches  and  leaves  (photo,  left).  The  fungus   produces  toadstools,  and  these  produces  spores.  However,  the  toadstools  are  not  often  seen.     Spread  of  the  fungus  is  thought  to  occur  as  follows:   • It  grows  along  the  branches  as  white  threads,  extending  onto  the  leaf  stalks  and  then  over   the  surface  of  the  leaf  blades,  which  turn  brown  and  die;   • From  tree  to  tree  when  infected  branches  fall  from  shade  trees;   • As  airborne  spores  released  from  toadstools  that  form  in  wet  weather.       As  the  leaves  are  infected,  they  turn  dark  brown  and  die  (photo,  right),  but  even  though  they   are  no  longer  attached  to  the  branches,  they  remain  suspended  in  place  by  the  threads  of  the   fungus.    

Detection and  Inspection   Look  for  patches  of  dead  leaves,  held  in  place  by  white  threads.  The  fungus  can  be  more   clearly  seen  over  the  leaf  blades  when  they  are  wet  (photo,  left).    

Management CULTURAL  CONTROL   Prune  out  the  infected  leaves  and  branches;  this  is  the  best  way  of  managing  outbreaks  of   white  thread.  The  prunings  should  be  taken  out  of  the  plantation  and  burnt.   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

CHEMICAL CONTROL   Chemical  control  is  not  recommended  for  this  disease.  

Horsehair blight   Common  name:  Horse  hair  blight   Scientific  name:  Marasmius  crinis-­‐equi.  

The  fungus  is  often  thought  to  cause  a  disease,  but  it  does  not.  The  threads  are  brown  to  black   resembling  horsehair.  The  fungus  grows  over  the  healthy  leaves,  but  does  not  infect  them.   However,  when  the  leaves  break  naturally  from  the  stems,  they  are  held  in  place  by  strands  of   the  fungus;  this  gives  the  appearance  that  the  fungus  has  killed  them.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Yam Dieback    

Extension Fact  Sheet  

16

Common names:  Yam  dieback,  Lightning  disease   Scientific  name:  Glomerella  cingulata  (it  also  has  the  name  of  Colletotrichum  gloeosporioides).   Glomerella  is  the  sexual  stage  of  the  fungus.  The  disease  is  often  referred  to  as  Anthracnose  of   yam.     Hosts:  The  fungus  exists  as  many  strains,  which  attack  crops  and  weeds.  Some  of  the  strains   infect  several  hosts.  Yam  (Dioscorea  alata)  is  a  major  host;  other  yams,  for  instance,  pana  (D   esculenta)  and  African  yam  (D  rotundata-­‐cayanensis)  are  not  hosts  or  show  only  occasional   leaf  spots.      

Damage The  fungus  is  damaging  during  wet  weather.  Leaf  spots  occur  (photo,  left)  and  these  produce   masses  of  spores.  On  susceptible  varieties,  leaves  quickly  turn  black  (photo,  lower  right)  during   long  periods  of  rain,  for  instance,  during  cyclones.  Shoots  are  destroyed  and  the  stems  die   back.  New  shoots  grow  from  the  planting  piece,  but  these  also  become  black  and  die  back.   Plants  can  be  killed  without  producing  tubers  or  each  shoot  produces  several  small  tubers   before  it  dies.       The  blackening  is  so  sudden  on  some  varieties  of  yam  that  farmers  say  the  yams  have  been   struck  by  lightning.  

Biology and  Life  Cycle   It  is  not  known  for  certain  where  the  fungus  comes  from.  There  are  three  possibilities:     • It  is  in  the  soil;     • It  is  in  the  planting  material;  and     • It  comes  from  other  plants,  weeds  or  crop  plants.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   It  is  most  likely  that  it  comes  from  other  weeds  and  crops.  In  the  Caribbean,  tubers  are   infected  and  these  are  a  source  of  the  fungus.  Infection  of  the  tubers  has  not  been  found  in   Solomon  Islands.  Here,  the  fungus  has  been  found  on  other  crops  and  weeds.     Symptoms  depend  on  rainfall  and  the  susceptibility  of  varieties.  On  young  leaves,  the  spots   may  enlarge  rapidly  and  sometimes  merge.  On  some  varieties,  only  the  young  veins  are   infected;  in  this  case  the  leaves  become  cup-­‐shaped  as  they  expand  (photo,  top  right).  On   older  leaves,  pinpoint  spots  develop  that  do  not  expand.  Usually,  the  young,  infected  leaves   fall  early.     Spores  are  produced  in  tiny,  dish-­‐like  structures  in  the  spots  and  are  splashed  by  rain  onto   other  leaves  and  stems.  They  germinate  like  a  seed,  infect  and  produce  more  spots  and  spores.   On  older  leaves,  they  germinate,  but  do  not  infect  or  only  produce  pinpoint  spots.  On  some   varieties,  large  numbers  of  spores  on  the  old  leaves  cause  the  leaves  to  turn  black,  especially   when  they  are  exposed  to  sunlight.  

Detection and  Inspection   Look  for  brown  leaf  spots,  sometimes  with  a  yellow  halo,  that  are  typical  of  infection.  Look  for   plants  where  older  leaves  go  black  during  long  periods  of  rain,  and  shoots  die  back.  Tuber   infection  has  not  been  detected  in  the  Pacific,  but  it  is  important  to  inspect  planting  material   very  carefully,  and  only  use  pieces  that  are  healthy.  

Management CULTURAL  CONTROL   The  most  important  cultural  control  measure  is  to  plant  early,  in  August  and  September,  so   that  plants  are  at  the  tops  of  their  supporting  poles  before  the  storm  season.  Other  measures   have  been  suggested,  but  their  usefulness  is  in  doubt:   • Interplant  with  maize;   • Do  not  weed  when  the  plants  are  wet;   • Crop  rotation  –  i.e.,  do  not  plant  yams  on  the  same  land,  one  year  after  another;   • Bury  plant  remains  after  harvest;  and   • Avoid  damage  to  the  tubers  at  harvest.    

RESISTANT VARIETIES   Varieties  differ  in  resistance  to  the  disease;  some  are  resistant  at  all  stages  of  growth,  others   only  when  mature,  when  they  have  a  full  canopy.  Farmers  should  be  advised  to  select  those   that  show  resistance.  If  susceptible  varieties  are  also  planted,  not  only  is  there  a  chance  that   the  disease  will  destroy  them,  but  also  they  will  increase  disease  pressure  on  the  more   resistance  types.  Variety  Kinabeyo  from  the  Philippines  is  an  example  of  a  resistant  variety.  See   Kastom  Gaden  Association  for  supplies.    

CHEMICAL CONTROL   Although  fungicides,  for  instance,  benomyl  (no  longer  manufactured),  chlorothalonil,  copper,   dithiocarbamates  (e.g.,  mancozeb)  have  been  recommended  in  the  Pacific  and  Caribbean,  they   can  only  delay  the  start  of  an  epidemic.  They  are  not  effective  during  long  rainy  periods.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Banana Scab  Moth  

Extension Fact  Sheet  

17

Common name:  Banana  scab  moth                                                                             Scientific  name:  Nacoleia  octasema  (previously  Lamprosema  octasema).   Hosts:  Banana,  plantain,  Heliconia  and  Pandanus.    

Damage The  caterpillars  do  the  damage  (photos,  above,  left  &  right).  After  hatching  they  feed  on  the   skin  of  the  young  fruit,  while  hiding  in  protected  areas  between  the  fingers  and  the  fruit  stalk.   Sometimes  they  eat  through  the  skin  and  feed  on  the  pulp  of  the  banana.  Damaged  areas  form   a  black  scab  (photo,  top  right).  

Biology and  Life  Cycle   Eggs  are  laid  in  the  early  evening  on  or  near  to  an  emerging  banana  bunch.  The  eggs  are  flat,   oval-­‐shaped  and  about  1.3  mm  across.  They  are  laid  singly  or  in  clusters  of  up  to  30  and  look   like  overlapping  fish  scales.       The  caterpillars  hatch  after  about  4  days  and  move  to   the  young  fruit  under  the  tightly  closed  bracts  (the   leaves  around  the  young  bunches)  to  feed.  As  the  bracts   and  hands  lift  from  the  bunch  stalk,  the  caterpillar   moves  to  the  next  closed  hand.  When  newly  hatched,   the  caterpillars  are  about  1.5  mm  long  and  clear  yellow;   when  fully-­‐grown,  they  are  up  to  50  mm  long,  and  vary   from  pinkish-­‐grey  to  very  dark  brown.     After  feeding  for  about  2  weeks,  the  caterpillars  are  ready  to  pupate.  They  spin  a  thin  silken   cocoon,  adding  some  rubbish,  which  helps  to  hide  them.  Inside  the  cocoons,  the  caterpillars   turn  into  brown  pupae.  The  cocoons  are  either  on  the  banana  plant  or  nearby  in  the  leaf  litter.     After  8-­‐10  days,  the  adult  moths  emerge;  they  are  a  pale  straw  colour,  with  a  wingspan  of   about  30  mm.  They  have  a  row  of  small  black  dots  around  the  edges  of  the  wings  (photo,   below).  Moths  hide  during  the  day;  they  mate  and  lay  eggs  in  the  early  evening.   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S    

Detection and  Inspection   Look  at  the  young  developing  fruit.  Look  for  feeding  damage  -­‐  black  scabs  on  the  skin,  or   caterpillar  droppings.  Banana  bunches  should  be  inspected  when  bracts  have  begun  to  lift,  but   before  they  start  to  fall.  

Management NATURAL  ENEMIES   The  caterpillars  are  attacked  by  many  kinds  of  tiny  wasps  that  are  hard  to  see.  Spiders  and   other  general  predators  also  attack  them.  In  general,  these  natural  enemies  are  not  enough  to   reduce  damage  to  acceptable  levels.      

CULTURAL CONTROL   • •

Inspect the  banana  crop  daily  for  emerging  flower  stalks  -­‐  by  the  time  flower  stalks  have   bent  horizontally,  shortly  after  emergence,  some  fruit  damage  may  already  have  occurred;   Partly  or  completely  remove  the  flower  bracts,  then  spray  the  fruit  with  water,  or  dust   them  with  ashes.  This  will  reduce  the  damage.  

CHEMICAL CONTROL   In  Australia,  chlorpyrifos,  bifenthrin,  acephate,  and  bendiocarb  are  the  recommended   chemicals  for  bunch  injection;   • Inject  when  the  bunch  is  still  upright  in  the  throat  of  the  plant.  Inject  20  to  40  ml  of  dilute   insecticide  about  a  third  of  the  way  down  from  the  top  of  the  spear.  Injections  above  or   below  this  will  either  damage  the  fruit  or  not  be  effective;   • Use  biopesticides.  These  are  biological  insecticides  that  cause  insect  diseases.  Use  the   following,  instead  of  sprays  of  water  and  dusts:   o Spinosad  (Success),  Beauvaria  bassiana,  Metarhizium  anisoplea,  and  Bt  -­‐  Bacillus   thuringiensis  (Dipel).  Spinosad  and  Bt  are  sometimes  sold  in  Honiara;   o But  note,  biopesticides  are  expensive,  but  they  do  not  kill  the  natural  enemies,  as  do   synthetic  insecticides.       Spraying  with  chemicals  (rather  than  injecting  them)  often  does  not  work  against  this  pest,   because  the  insect  is  so  well  hidden.  Therefore,  some  commercial  growers  lift  or  remove  the   flower  bracts  and  dust  or  sprays  insecticide  onto  the  fruits  after  the  flow  has  bent  over.  This   method  can  stop  some  damage  but  not  all.         •

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Pod-­‐Sucking Bug  

Extension Fact  Sheet  

18

Common name:  Bean  pod-­‐sucking  bug                                                                               Scientific  name:  Riptortus  serripes  and  Riptortus  linearis.     Hosts:  Legumes,  such  as  long  bean,  soybean,  and  mung  bean.  They  may  also  attack  rice  and   clover.    

Damage Damage  is  done  by  adults  (body  length  25  mm)  and  nymphs  (they  look  like  ants)  feeding  on   the  pods  and  seeds  (photo,  top  left  &  right  &  lower  left).  The  feeding  causes  the  pods  to  rot,  or   to  develop  without  seeds  inside.  This  insect  can  cause  a  lot  of  damage  to  bean  crops.  

Biology and  Life  Cycle   Riptortus  lays  its  eggs  on  the  bean  leaves  and  other  plants;  usually  the  eggs  are  laid  singly.   Both  adult  and  nymphs  sting  the  beans  in  the  pods  and  suck  their  juices,  so  that  the  beans   cannot  mature.  The  pods  turn  brown,  shrivel  and  die.    

Detection and  Inspection   Look  at  the  pods  and  under  the  leaves;  look  for  ant-­‐like  bugs  (photo,  top  right).  Look  closely   for  small  holes  and  damaged,  shrivelled  pods.    

Management CULTURAL  CONTROL   Plant  long  beans  near  Bixa  (photo,  lower  right),  a  method  recommended  by  a  farmer  on   Malaita  (see  leaflet:  What  is  the  pest  spoiling  your  long  beans?).  Bixa  is  known  as  the  Lipstick   tree,  because  of  its  seeds.  They  are  deep  red,  soft,  and  children  use  them  to  paint  their  faces,   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   lips  included.  When  the  fruits  open,  they  attract  large  numbers  of  Riptortus.  The  insects  feed  on   the  seeds,  preferring  them  to  the  seeds  of  beans.  In  this  way,  the  insects  are  ‘trapped’  on  the   Bixa,  and  long  beans  escape  damage.        

CHEMICAL CONTROL   •

Insecticides have  not  been  tested  against  Riptortus  in  Solomon  Islands.  It  is  likely  that   synthetic  pyrethroids  would  be  effective,  such  as  lambda  cyhalothrin  or  permethrin.  See   your  MAL  extension  officer  for  details.   A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.  

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Amblypelta Bug    

Extension Fact  Sheet  

19

Common names:  Cassava  shoot  dieback,  Coconut  premature  nut  fall     Scientific  name:  Amblypelta  cocophaga  and  other  species.     Hosts:  Coconut,  causing  premature  nut  fall;  shoot-­‐tip  dieback  of  Eucalyptus  deglupta  and   cassava,  and  cocoa  pod  distortion.    

Damage As  Amblypelta  feeds  it  injects  a  poison.  In  coconuts,  the  young  fruit  (buttons  or  nuts)  fall;  in   Eucalyptus  and  cassava,  the  shoots  wilt  and  die,  and  cankers  form  on  the  stems  (photo,  left);  in   cocoa,  sunken  black  spots  occur  and  young  pods  become  distorted  as  they  grow.         Early  or  premature  nut  fall  of  coconuts  in  Solomon  Islands  has  been  a  major  problem  in  some   parts  of  the  country  since  the  1930s,  and  has  been  investigated  by  a  number  of  entomologists.   The  islands  of  Guadalcanal,  Malaita  and  Nggela  are  those  most  affected.  Loss  of  coconuts  was   estimated  to  be  between  10  and  20%,  but  on  individual  farms  on  Malaita  and  Nggela  losses   were  devastating.  It  is  difficult  to  be  accurate  as  nut  fall  is  patchy,  depending  on  the   distribution  of  various  ant  species  and  their  interaction  with  Amblypelta.  Also,  coconut  has  a   natural  fruit  drop  of  over  60%.     Another  problem  occurred  in  the  1980s.  Amblypelta  dieback  was  seen  on  Eucalyptus,   threatening  the  success  of  forest  replanting  schemes  on  Kolombangara,  in  particular.   Amblypelta  caused  death  of  the  leading  shoot.  After  a  while,  other  shoots  developed,  but   these,  too,  were  attacked  and  the  trees  became  hedge-­‐like.  

Biology and  Life  Cycle   The  adult  Amplypelta  is  about  20  mm  long,  the  legs  are  pale  green,  while  the  wings  are  pale-­‐ brown  (photo,  above  right).  Females  lay  eggs  on  or  near  the  host  plant.  Nymphs  hatch  a  few   days  later.  They  are  dark  brown  with  long  legs  and  antennae;  they  look  like  adults  without   wings.  Nymphs  feed  in  the  same  way  as  adults,  and  on  the  same  plants,  using  needle-­‐like   mouthparts.  It  is  not  known  if  nymphs  inject  poison,  but  it  is  likely.  Wings  develop  when   nymphs  become  adult,  3-­‐4  weeks  after  emerging  from  the  egg.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  a  bug  with  pale  green  body,  long  legs,  and  pale  brown  wings.  Look  for  the  very  long   needle-­‐like  mouth,  almost  as  long  as  its  body.  The  young  bugs  look  like  the  adults,  except  they   are  smaller.  Look  for  wilting  shoots  of  cassava  and  Eucalyptus,  and  look  for  stem  cankers.  On   coconuts,  look  for  palms  that  shed  large  numbers  of  young  nuts.    

Management NATURAL  ENEMIES   In  1937,  four  egg  parasites  were  collected  in  Indonesia  and  released  in  Solomon  Islands  against   A.  cocophaga.  However,  these  did  not  control  the  pest.  Later,  a  Tachnid  fly  was  introduced   from  Queensland,  but  this,  too,  was  unsuccessful.  A  Braconid  wasp  was  found  on   Kolombangara  infecting  late  stage  nymphs;  this  too  does  not  control  the  populations   successfully.       Amblypelta  is  found  at  low  numbers  on  coconuts  and  probably  other  hosts.  The  damage   caused  by  one  adult  is  significant,  so  it  is  unlikely  that  parasites  could  reduce  numbers  enough   to  prevent  economic  losses.    

MANIPULATION OF  ANT  SPECIES   Attempts  over  many  years  to  control  premature  nut  fall  have  tried  to  encourage  some  ant   species  whilst  removing  others.  Mostly,  this  means  removing  Pheidole  megacephala  and   Iridomyrmex  cordatus  and  encouraging  Oecophylla  smaragdina.  The  idea  is  to  have  ant  species   that  discourage  Amblypelta  from  feeding  on  the  young  coconuts.  Oecophylla  invades  the  palm   in  search  of  food  and  at  the  same  time  disturbs  Amblypelta  from  feeding.       Removal  of  P.  megacephala  using  herbicide  and  insecticide  applied  to  the  base  of  the  trunk  is   possible.  Once  removed,  soursop  trees  are  planted  among  the  coconuts,  the  fruits  of  which   readily  become  colonised  by  mealybugs,  which  are  ‘farmed’  by  Oecophylla  for  their  honeydew.   The  success  of  this  strategy  was  patchy,  however,  as  the  ant  populations  keep  changing.  Also,   removal  of  I.  cordatus  is  difficult  as  it  makes  its  home  in  the  crown  of  the  palm,  not  in  the   ground.     In  more  recent  years,  a  fire  ant,  Wasmannia  auropuntata,  has  become  established  throughout   Solomon  Islands.  This  ant  is  capable  of  protecting  palms  against  Amblypelta  as  well  as   displacing  I.  cordatus  and  probably  P.  megacephala.  It  is,  however,  a  fire  ant  and  it  is   unpleasant  working  in  plantations  of  coconut  or  cocoa  where  it  is  present.    

CHEMICAL CONTROL   A  number  of  insecticides  applied  as  sprays  or  as  trunk  injections  from  different  chemical   groups  have  been  tested  against  premature  nut  fall.  Some  are  effective;  however,  the  height   of  coconut  palms  prohibits  easy  application,  and  it  is  unlikely  that  such  treatments  are   economic.  To  be  effective,  they  need  to  be  applied  frequently,  perhaps  8-­‐10  times  a  year.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Diamond Back  Moth  

Extension Fact  Sheet  

20

Common  name:  Diamond  back  moth                                                                                                     Scientific  name:  Plutella  xylostella.   Hosts:   Cruciferous  vegetables  -­‐  head  cabbage;  Chinese  cabbage;  radish;  cauliflower  and   broccoli;  non-­‐crucifer  plants:  Amaranthus  and  watercress.    

Damage The  caterpillars  do  the  damage.  The  first  two  stages  are  small  and  feed  by  mining  the  leaf;   later,  when  they  are  too  large  to  mine,  they  burrow  through  the  leaf.  The  result  is  1-­‐2  cm  wide   cavities  on  the  lower  leaf  surface  leaving  the  waxy  layer  intact,  which  gives  the  appearance  of   windows  in  heavily  damaged  plants.  Economic  damage  is  most  severe  when  heading  begins.   The  caterpillars  tunnel  into  the  heads  of  cabbages.       Note:  other  pests  often  occur  on  ball  cabbages  along  with  this  moth,  and  the  combined   damage  is  considerable.  The  other  pests  are  cabbage  webworm,  Hellula  undalis;  cutworm,   Spodoptera  litura;  and  cabbage  cluster  caterpillar,  Crocidolomia  pavonana.  (See  Fact  Sheet  no.   78  for  Crocidolomia.)  

Biology and  Life  Cycle   The  eggs  are  small  (0.4  mm  long),  cylindrical  or  oblong,  white  when  laid,  changing  to  yellowish   brown  as  they  mature  and  ready  to  hatch.  The  eggs  are  mostly  laid  singly  or  in  groups  of  two   or  three,  on  the  lower  leaf  surface  along  major  veins.  One  adult  female  lays  100-­‐150  eggs  in  a   life  span  of  3-­‐7  days.  The  incubation  period  ranges  from  3-­‐8  days  depending  on  the   temperature.     There  are  four  larval  or  caterpillar  stages.  At  hatching,  the  caterpillars  are  light  brown;  later,   when  fully  grown,  they  are  dark  green  (photo,  right).  When  disturbed,  the  larvae  wriggle   backwards,  and  may  drop  from  the  leaf  on  a  silk  thread.  The  larval  period  ranges  from  14-­‐28   days,  after  which  they  make  a  silken  cocoon  and  pupate.     The  pupa  is  dark  green  or  light  brown,  about  10  mm  long,  and  usually  stuck  to  the  underside  of   the  leaf.  Pupation  lasts  5-­‐10  days.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   After  pupation,  the  adult  moth  emerges  from  the  cocoon.  It  is  about  10  mm  long  with  a  13  mm   wingspan,  dark  brown  with  three  white  diamond-­‐shaped  patterns  on  its  back;  these  give  the   moth  its  common  name  (photo,  left).  The  adult  lives  for  up  to  35  days.     The  life  cycle  is  complete  in  less  than  1  month,  depending  on  the  temperature.  The  moth  is   most  active  at  night.  

Detection and  inspection   The  onset  of  Diamond  back  moth  infestation  can  be  monitored  by:   • Visiting  the  field  everyday,  looking  for  any  adults  or  larvae  on  the  plants;   • Putting  yellow  sticky  traps  in  the  field  to  catch  flying  adults;   • Putting  sticky  traps  baited  with  Diamond  back  moth  sex  pheromone  to  trap  male  adults.  

Management NATURAL  ENEMIES   There  are  several  parasitioids  of  the  different  stages:  eggs  -­‐  Trichogrammatoidea  bactrae;     caterpillars  -­‐  Cotesia  plutellae,  Diadegma  semiclausum,  Microplitis  plutellae,  Oomyzus   sokolowskii;  pupae  -­‐  Diadromus  collars.    

CULTURAL CONTROL   • • • • •

• •

Always start  with  healthy,  insect-­‐free  seedlings;   Hand  pick  larvae  when  numbers  are  low;   Destroy  crop  residues  after  harvest,  and  crucifer  weeds  before  planting  and  during  the   cropping  period;   Grow  head  cabbages  during  the  cooler  times  of  the  year  (June-­‐November)  to  avoid   infestations  -­‐  done  by  some  farmers  on  the  Guadalcanal  Plains;     Grow  collards,  Brassica  oleracea  acephala  cv.  Vates,  as  a  trap  crop.  Trap  crops  for  the   other  species  are:  radish  and  green  mustard  (B.  juncea)  for  Hellula  undalis);  Chinese   cabbage  (B.  pekinensis  cv.  Tempest)  or  flowering  green  mustard  for  Crocidolomia   pavonana.  (Note  that  the  latter  was  also  useful  as  a  trap  crop  for  Halticus  tibialis);   Where  farmers  have  the  resources,  grow  plants  under  nets  or  in  green  houses;   For  watercress,  grown  on  rafts  in  the  river,  sinking  one  half  for  30  min  and  then  the  other   end,  to  drown  the  caterpillars  is  a  measure  worth  trying.  Drown  one  half  of  the  plants,   then  the  other  half,  is  done  so  that  spiders  are  able  to  survive.  Spiders  are  natural  enemies   of  the  Diamond  back  moth  caterpillars.    

CHEMICAL CONTROL   • •

If pesticides  are  used,  there  is  need  for  careful  choice.  If  one  chemical  is  used  all  the  time,   it  is  likely  that  the  Diamond  back  moth  will  develop  resistance  to  it;   Those  products  that  are  recommended  are  plant-­‐derived  products,  such  as  chilli  (with  the   addition  of  soap),  and  synthetic  products  that  contain  disease-­‐causing  organisms,  such  as   spinosad  (Success)  and  Bt  -­‐  Bacillus  thuringiensis.  Spinosad  and  Bt  are  sometimes  sold  in   Honiara.   Indoxacarb  (Steward),  a  new  product  with  a  novel  action  is  not  yet  available  in  Honiara.  

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Fruit Flies  

Extension Fact  Sheet  

21

Common  name:  Fruit  flies   Scientific  names:  Mango  fly  (Bactrocera  frauenfeldi)  (below,  left);  Melon  fly  (Bactrocera   cucurbitae)  (below,  2nd  left);  Breadfruit  fly  (Bactrocera  umbrosa)  (below,  3rd  left);  Solomon  fly   (Dacus  solomonensis)  (below,  right).  There  are  many  more  fruit  fly  species  in  Solomon  Islands,   but  these  are  major  pests.   Hosts:  Mango  fly  has  a  wide  host  range;  those  hosts  that  are  of  importance  to  subsistence  and   commercial  agriculture  are:  avocado,  black  sapote,  breadfruit,  capsicum,  carambola,  cut  nut,   golden  apple,  grapefruit,  guava,  jackfruit,  kumquat,  mangoes,  Malay  apple,  papaya,  paper   mulberry,  passion  fruit,  plantain,  pomelo,  sapodilla,  snake  gourd,  sour  orange,  soursop,   Tahitian  chestnut  and  tropical  almond.  Wild  hosts  are  Indian  laurel,  figs,  and  many  forest   fruits.    Breadfruit  fly  infests  breadfruit,  jackfruit  and  bitter  gourd.  Solomon  fly  attacks   cucumber,  pumpkin  and  particularly  snake  gourd.  Melon  fly  hosts  are  cucurbits,  including   watermelon,  cucumber,  pumpkin,  snake  gourd,  bitter  gourd  and  ivy  gourd.    

Damage Eggs  are  laid  in  fruit,  and  maggots  cause  the  fruits  to  rot.  Melon  fly  may  also  lay  eggs  in  flower   buds  and  stems.  It  is  an  important  fruit  fly,  destroying  crops  of  pumpkin  and  snake  gourd.    

Biology and  Life  Cycle   Female  flies  lay  eggs  in  fruit,  leaving  small  holes  in  the  skin.  Eggs  are  white  or  pale  yellow,   about  0.8  mm  long  and  0.2  mm  wide.  As  the  female  lays  eggs,  it  also  adds  bacteria  from  the   fruit  surface;  these  help  rot  the  fruit  and  provide  food  for  the  larvae  or  maggots.     The  eggs  hatch  after  1  or  2  days,  with  the  maggots  feeding  on  rotting  fruit  flesh.  Maggots  are   white,  and  their  body  tapers  to  a  pointed  head  containing  a  pair  of  black  mouth-­‐hooks.  The   maggots  grow  to  different  sizes:  mango  fly  up  to  8  mm,  melon  and  breadfruit  fly  up  to  11  mm,   and  Solomon  fly  even  larger.  There  are  three  moults.  Maggots  usually  live  from  between  1  and   2  weeks.  When  fully  grown  they  drop  to  the  ground  and  burrow  into  the  soil.  Their  skins   harden  to  form  brown,  barrel-­‐shaped  pupae.  These  hatch  into  adult  flies  after  1  or  2  weeks.     Mango  fly  adults  are  mostly  black,  about  6  mm  long,  with  a  dark  stripe  across  the  wings.   Melon  fly  adults  are  orange-­‐brown,  about  8  mm  long,  with  three  yellow  stripes  along  their   backs,  and  two  brown  spots  near  the  wing  tips.  Breadfruit  fly  adults  are  about  8  mm  long,  with   bold  black,  yellow  and  orange  body  markings,  and  three  wide  brown  bands  on  the  wings.   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Solomon  fly  adults  look  like  wasps  with  a  slim  waist,  have  brown  bodies  about  12  mm  long,   and  their  wings  have  a  brown  band  along  the  front  edge.     Flies  mate  and  lay  eggs  about  2  weeks  after  pupation.  Melon  and  Breadfruit  flies  mate  at  dusk,   while  Mango  fly  mates  at  any  time.  Female  flies  need  protein  to  develop  eggs.  Melon  fly   females  lay  more  than  1000  eggs,  and  live  for  about  5  months,  longer  than  the  other  species.    

Detection and  inspection     Look  for  rotten  fruit,  and  small  holes  in  the  skin.  Open  up  fruits  and  look  for  maggots  inside.   Rear  maggots  to  determine  species.  Distinctive  features  are:  Melon  fly:  yellow  stripe  in  the   middle  of  the  upper  body  between  the  wings;  black  T  on  the  rear  body;  dark  patches  on  edge   of  wings.  Mango  fly:  reddish  brown  with  yellowish  abdominal  cross  bands,  transparent  wings   with  small  brown  spots  on  the  tips.  Breadfruit  fly:  mix  of  black  with  yellow  stripes.,  and  wings   with  broad  black  bands.  Solomon  fly:  large,  reddish-­‐brown.  Lures  are  used:  either  Cue-­‐lure,  to   attracts  mango,  melon  and  Solomon  fly,  or  methyl  eugenol,  to  attract  breadfruit  fly.  

Management QUARANTINE:  Melon  fly,  which  entered  Solomon  Islands  from  Papua  New  Guinea  in  1984,  is  not   present  yet  in  Makira,  Rennell/Bellona  and  Temotu  Provinces.     NATURAL  ENEMIES:  Fruit  fly  maggots  are  parasitised  by  small  wasps.  Spiders,  ants,  assassin  bugs   and  beetles  feed  on  maggots,  pupae  and  adults.  Weaver  ants  (Oecophylla)  stop  flies  from   laying  eggs.  Chickens,  pigs  and  flying  foxes  eat  the  fruit  and  maggots.     CULTURAL  CONTROL   • • •

Collect fallen,  damaged  and  overripe  fruits,  and  bury  them  (at  least  50  cm),  feed  them  to   pigs  or  seal  them  inside  plastic  bags  and  put  in  direct  sunlight  for  several  hours;     Choose  varieties  of  fruits  and  vegetables  that  are  less  susceptible  to  attack;  and,  if   possible,  harvest  early  to  avoid  infestation;   Form  a  bag  with  a  double  layer  of  newspaper  over  the  fruit  and  staple  or  sew  in  place.   Effective  for  guava,  mango  and  carambola.  Use  leaves  of  pandanus,  betel  nut,  sago  palm   or  swamp  taro,  after  softening  over  a  fire.  In  PNG,  whole  banana  bunches  are  bagged   inside  banana  leaves  to  stop  banana  fly  and  to  improve  market  look;   Encourage  weaver  ants  (Oecophylla),  by  placing  bamboo  poles  as  ‘roads’  from  nests  to   new  areas.  Useful  in  citrus,  native  almond  and  mango.    

CHEMICAL CONTROL:  Use  insecticides  as  cover  sprays,  but  they  will  also  kill  beneficial  insects.   Better  if  they  are  used  together  with  baits  as  follows:   •

Protein-­‐bait technique.  A  protein  and  an  insecticide  are  spot-­‐sprayed  around  crops.  The   protein  is  made  from  yeast,  and  can  be  bought  in  PNG  (mango  fly  on  guava  and   carambola),  Tonga  and  Vanuatu.  Useful,  but  needs  farmers  to  synchronise  efforts.   Male-­‐annihilation-­‐technique.  Male  fruit  flies  are  killed,  so  females  cannot  mate  and  lay   eggs.  A  high  density  of  bait  stations  are  arranged  on  a  grid  -­‐  400  per  km2  or  1  every  20  m  -­‐   and  treated  with  a  male  lure  (Cue-­‐lure  or  methyl  eugenol)  and  an  insecticide  (fipronil).  The   baits  are  made  of  fibreboard,  cardboard  or  coconut  husk.  An  entire  orchard  or  village  is   covered,  plus  a  50  m  buffer  zone  around  the  outside.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sliperi Kabis  Flea  Beetle  

Extension Fact  Sheet  

22

Common names:  Sliperi  kabis  or  Neka  flea  beetle,  Bubulu  (on  Malaita)1                                                                                                           Scientific  name:  Nisotra  basselae.   Hosts:  Sliperi  kabis  (Abelmoschus  manihot),  possibly  Hibiscus  tilaceous  (under  lab  conditions,   but  not  seen  in  the  field);  not  on  Sida,  nor  the  garden  hibiscus,  Hibiscus  rosa-­‐sinensis.      

Damage  

Adult beetles  feed  on  leaves  creating  many  small  (1-­‐5  mm  diameter)  holes  (photo,  right).  The   damage  is  so  severe  that  in  many  places  in  Solomon  Islands  people  have  stopped  growing   sliperi  kabis.  The  larvae  feed  on  small  roots,  especially  the  tiny  root  hairs.  Whether  this  affects   the  growth  of  the  plant  is  unknown.  

Biology and  Life  Cycle   Eggs  are  laid  singly  or  in  small   batches  just  below  the  surface  of   the  soil.  They  hatch  after  8-­‐9  days.   The  larvae  remain  in  the  soil  for  12-­‐ 18  days,  feeding  on  small  roots.   They  moult  twice  before  they   pupate.  After  pupating  for  4-­‐6  days,   adults  emerge  from  the  soil.  Males   emerge  first,  taking  6-­‐8  days  to   become  sexually  mature;  females   take  3-­‐5  days.  The  adults  disperse   by  walking,  jumping  and  flying.   They  may  drop  to  the  ground  if   disturbed.       The  number  of  generations  per  year  is  unknown.  Research  into  the  biology  of  the  beetle  is   being  done  in  Solomon  Islands.   1

Information supplied by Maclean Vagalo, MAL Director of Research, Honiara, and Chris Reid, Entomologist, Australian Museum, Sydney.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  inspection   Look  for  small  holes  in  the  leaves  and  the  presence  of  beetles.  The  adult  beetles  are  about  4   mm  long  and  can  be  found  on  both  sides  of  the  leaves.  The  head  and  part  of  the  section  below   are  orange/brown  (photo,  left).  The  wing  cases  are  black.  The  beetles  are  less  obvious  during   the  hotter  times  of  the  day,  when  they  move  under  the  leaves.    

Management QUARANTINE   Temotu,  and  Rennell  and  Bellona  Provinces  are  free  from  of  the  beetle.  Therefore,  no  leaves  of   sliperi  kabis  or  other  parts  of  the  plants  should  be  taken  there.  Extension  services  should   constantly  remind  people  of  this,  with  messages  on  the  radio  and  in  newspapers.    

NATURAL ENEMIES   Parasites  of  the  adults  include  nematode  worms  and  mites.  The  adults  do  not  seem  to  be   affected  by  the  presence  of  the  fire  ant,  Wasmannia  auropunctata.  Nisotra  may  be  toxic  to   visual  predators,  like  birds  and  lizards.    

CULTURAL CONTROL   There  are  a  number  of  possibilities:   • Plants  grown  under  shade  may  have  fewer  beetles;  however,  too  much  shade  gives  poor   plant  growth;   • Thick  mulches  of  straw,  grass  or  other  organic  materials  (several  centimetres  thick)  may   prevent  female  beetles  from  laying  eggs  at  the  base  of  the  stems;   • There  is  some  evidence  that  planting  in  clover  reduces  infestations;   • Plant  sliperi  kabis  far  from  plants  infested  with  the  beetle;  the  beetles  do  not  fly  long   distances;   • Plant  more  sliperi  kabis  in  the  wet  season  when  beetle  numbers  are  lower;   • Hand  pick  the  beetles  when  infestations  have  just  started;  this  will  delay  beetle   populations  reaching  damaging  numbers  later;   • Cultivate  the  soil  at  the  base  of  the  plants  to  expose  eggs,  larvae  and  pupae  to  the  sun  and   predators.    

CHEMICAL CONTROL   • • •

Orthene (acephate)  is  often  used  in  Solomon  Islands;  other  insecticides,  such  as  synthetic   pyrethroids  are  likely  to  be  effective  and  safer  to  use;   Lambda  cyhalothrin  and  permethrin  are  available  in  Honiara.  Before  these  chemicals  are   used,  farmers  should  read  the  instructions  on  their  safe  use;   A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  is  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sliperi Kabis  Shoot  Borer  

Extension Fact  Sheet  

23

Common name:  Sliperi  kabis  shoot  borer   Scientific  name:  Earias  vittella.   Hosts:  The  moth  attacks  sliperi  kabis  (Abelmoschus  manihot),  okra,  hibiscus,  and  tomato.    

Damage  

Caterpillars do  the  damage  by  feeding  inside  the  stems  (photo,  top  right).  The  tips  and  leaves   wilt  and  die  (photo,  left).  Caterpillars  also  feed  inside  fruits  and  pods  of  cotton  and  okra.  

Biology and  Life  Cycle   Adult  moths  lay  eggs  at  night,  singly,  on  shoots,  buds  and  young  fruit.  Eggs  are  light  blue-­‐ green,  round,  and  about  0.5  mm  across.  They  gradually  change  to  brown  just  before  hatching.       Eggs  hatch  into  caterpillars  in  the  early  morning,  after  3-­‐7  days.  The  caterpillars  may  move   some  distance  before  settling  to  feed  on  soft  growing  parts  of  the  plant.  Feeding  happens   during  the  day,  and  caterpillars  are  full-­‐grown  after  9-­‐17  days.  They  are  grey-­‐brown  with   orange  spots  and  a  black  head.  The  body  is  up  to  18  mm  long  and  3  mm  wide,  with  two  pairs   of  fleshy  bumps  on  each  body  segment  (photo,  top  right).       Mature  caterpillars  spin  a  silken  cocoon,  which  is  brown,  felt-­‐like,  and  shaped  like  an  upside-­‐ down  boat.  Cocoons  are  fastened  to  the  plant,  to  debris  on  the  ground,  or  within  cracks  up  to   30  cm  deep  in  the  soil.  Inside  the  cocoon,  the  caterpillar  turns  into  a  pupa  that  is  about  13  mm   long,  with  three  small  spikes  on  its  tail.  The  pupa  lasts  for  1-­‐2  weeks,  before  it  splits  open  and   an  adult  moth  comes  out.     Adults  live  for  up  to  1  month,  feed  on  nectar,  and  lay  up  to  500  eggs.  Adult  bodies  are  12  mm   long,  with  a  wingspan  of  about  2  cm  (photo,  lower  right).  They  are  mostly  white,  with  a  central   green  wedge  pattern  running  along  their  front  wings.  

Detection  and  Inspection   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Look  at  the  stem  tips  and  leaves;  look  to  see  if  the  tips  or  branches  are  wilting  and  dying.  Look   closely  for  small  holes  in  the  stem  below  the  dying  tip.  The  caterpillars  push  their  waste  out  of   these  holes.  This  is  often  very  noticeable.  Break  the  stem  near  this  hole  to  find  the  caterpillar   in  its  tunnel.  

Management NATURAL  ENEMIES   • • •

Small wasps  attack  the  eggs,  caterpillars  and  pupae;   Lacewings  and  ladybird  beetles  eat  the  eggs;    It  is  important  to  think  about  these  natural  enemies  when  considering  how  to  control   Earias.  If  insecticides  are  used,  use  ones  that  do  not  kill  these  beneficial  insects.  Preferably,   use  those  that  are  allowed  under  organic  vegetable  production.  

CULTURAL CONTROL   • • •

If the  sliperi  kabis  plants  are  severely  attacked,  pull  them  all  out  and  stop  growing  the   cabbage  for  a  few  weeks.  Plant  the  crop  in  another  garden;       Earias  is  less  abundant  during  wet,  humid  weather  and,  therefore,  growing  crops  during   the  wet  season  may  be  effective;   There  are  no  known  resistant  sliperi  kabis  varieties  in  Solomon  Islands.  Look  carefully  to   see  if  some  types  are  less  attacked  and,  if  they  are,  plant  more  of  those.  

BIOLOGICAL CONTROL   In  other  countries,  introduced  wasps  have  been  used  to  control  populations,  with  rates  of   parasitism  at  over  25%  in  eggs  and  35%  in  pupae.  Lacewings  are  used  as  egg  predators.  A   female  sex  pheromone  has  been  identified,  and  synthetic  formulations  have  shown  promise,   disrupting  mating  and  achieving  season-­‐long  control.  This  is  not  available  in  Solomon  Islands.    

CHEMICAL CONTROL   Since  populations  of  Earias  tend  to  build  up  slowly,  only  two  or  three  applications  of  chemical   pesticide  may  be  needed  to  reduce  numbers  in  a  crop.  In  Honiara  and  nearby  village,  Orthene   is  commonly  used  to  control  Earias.  The  following  alternatives,  made  from  bacteria,  are   recommended  (they  are  sometimes  sold  in  Honiara):   • Spinosad,  also  known  as  Success;   • Bt,  also  known  as  Bacillus  thuringiensis  kurstaki.     Pyrethrum  and  derris  insecticides  can  also  be  used;  pyrethrum  is  a  member  of  the  daisy  family   and  derris  is  a  shrubby  legume,  and  contains  rotenone.  They  are  fast  acting  against  insects  and   less  harmful  in  the  environment  compared  to  many  synthetic  products.  They  are  broken  down   quite  quickly  by  sunlight.  BUT  they  will  kill  natural  enemies,  too.  A  variety  of  Derris,  brought   many  years  ago  from  Papua  New  Guinea,  is  effective  as  a  spray.  It  contains  rotenone,  an   insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for  evaluation  by  growers.  Contact   those  organisations  for  plants  to  test.     Neem  seed  extract  can  be  used;  see  Kastom  Gaden  Association  for  seedlings.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Spider Mites  

Extension Fact  Sheet  

24

Common name:  Spider  mites   Scientific  name:  Tetranychus  species.  The  different  species  are  difficult  to  tell  apart  because   they  are  so  small  and  require  examination  using  a  high  power  microscope.  One  group,  known   as  two-­‐spotted  mites,  is  the  most  common,  infesting  over  200  species  of  plants.   Hosts:  Many  crops  are  host  to  spider  mites  in  Pacific  Island  countries,  among  them  okra,   papaya,  sweet  potato,  cassava,  tomato,  squash,  eggplant,  beans,  taro,  sliperi  kabis,  cucumber   and  other  cucurbits.      

Damage  

Spider mites  are  common  plant  pests.  They  have  needle-­‐like  mouthparts  and  use  them  to  suck   juice  from  the  leaves.  This  destroys  the  cells,  and  the  leaves  show  a  characteristic  white  to  pale   yellow  speckling,  usually  between  the  main  veins.  When  infestations  are  severe,  the  speckling   is  seen  all  over  the  leaf.  Two-­‐spotted  mites  make  webs  (like  spiders)  on  the  under  surface.  As   the  infestation  advances,  the  leaves  turn  yellow  and  die  prematurely.       The  extent  of  the  damage  caused  by  mites  often  depends  on  rainfall.  When  rainfall  is  low,  mite   populations  are  high  and  often  effect  yields.  On  taro,  for  instance,  yellowing  and  early  maturity   of  plants  occurs  and  corm  size  is  reduced.  Damage  is  particularly  severe  during  droughts  and,   presumably,  outbreaks  will  increase  with  climate  change.  

Biology and  Life  Cycle   The  eggs  are  round  and  relatively  large  in  comparison  to  the  size  of  the  adult;  they  are  laid  in   the  webbing  near  the  veins,  on  the  underside  of  leaves.       The  eggs  hatch  in  about  3  days,  producing  larvae  that  have  six  legs  and  are  colourless.  From   these,  nymphs  develop,  which  have  eight  legs;  they  moult  once  and  within  a  few  days  become   adult.  The  adults  are  about  0.5  mm  long,  with  males  smaller  than  females,  and  narrower   towards  the  back  end.  Each  female  lays  about  100  eggs.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Under  tropical  conditions  the  life  cycle  takes  only  7-­‐10  days  depending  on  temperatures.   Populations  develop  rapidly,  especially  during  periods  of  drought  when  damage  can  be   considerable.  The  adults  live  for  2-­‐4  weeks.       Two-­‐spotted  mites  vary  from  light  yellow  to  dark  green  or  brown.     Mites  produce  fine  silken  webs  -­‐  from  a  pair  of  glands  near  the  mouth.  When  infestations  are   high,  this  webbing  covers  all  or  part  of  the  leaf  and  becomes  very  noticeable.  The  webs  allow   the  mites  to  travel  from  infested  to  non-­‐infested  leaves;  also,  the  webs  are  caught  by  the  wind   and  help  the  mites  to  disperse.    

Detection and  Inspection   Look  at  the  underside  of  leaves,  particularly  near  the  veins  for  the  presence  of  mites,  using  a   hand  lens  and/or  a  microscope.  Look  for  webbing,  which  can  be  seen  when  mites  are  present   in  large  numbers.  The  tiny  spots  on  the  upper  leaf  surface  and  the  presence  of  webs  are  signs   of  their  presence.  Look  for  spots  on  the  mites;  the  spots  are  reddish-­‐brown  to  yellowish-­‐green,   depending  on  the  species.     A  good  way  to  detect  if  mites  are  present  is  to  place  a  sheet  of  white  paper  beneath  the  leaves   and  strike  the  leaves  sharply.  The  mites  fall  onto  the  paper  and  can  be  more  easily  seen  than   on  the  green  leaves.  

Management NATURAL  ENEMIES   Predatory  mites  keep  populations  of  spider  mites  in  check,  as  do  ladybird  beetles,  lacewing   larvae,  pirate  bugs,  big-­‐eyed  bugs  and  predatory  thrips.  Managing  mites  requires  preserving   natural  enemies;  in  most  cases  this  means  doing  nothing  to  harm  them.  It  also  means  not   using  pesticides.    

CULTURAL CONTROL   • •

A regular  spaying  of  leaves  with  water  will  keep  spider  mites  in  check.  This  technique  helps   conserve  natural  predators;   Check  that  cuttings,  tops,  etc.  are  free  from  infestation  before  planting  in  a  new  garden.  

CHEMICAL CONTROL   • •

If pesticides  are  used,  they  should  be  applied  carefully.  Rotate  between  different  chemical   groups,  to  prevent  resistance  developing  to  any  one  of  them;   Not  all  insecticides  kill  mites,  and  those  that  do  may  not  kill  all  the  stages.  Eggs  are   particularly  resistant  to  pesticides  and  so,  too,  are  larvae  and  nymphs,  especially  when   moulting,  as  they  do  not  feed.  More  than  one  application  is  needed  at  5-­‐10  days  apart;   Horticultural  oil  and  soaps  are  effective.  If  used,  test  them  on  a  few  plants  first,  to  see  if   they  cause  damage.  It  is  better  to  use  them  than  synthetic  pesticides,  since  they  are  less   toxic  to  people,  other  non-­‐target  organisms  and  the  environment.  However,  their  effect   may  depend  on  the  plant  and  the  species  of  mite;   Water-­‐stressed  plants  stimulate  mite  outbreaks,  and  hosing  plants  with  water  can   suppress  mite  populations,  but  this  is  not  a  practical  solution  for  large  plantings.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Spiraling Whitefly  

Extension Fact  Sheet  

25

Common  name:  Spiraling  whitefly                                                                             Scientific  name:  Aleurodicus  disperses.   Hosts:  Spiraling  whitefly  has  a  very  wide  host  range,  such  as  banana,  cassava,  citrus,  papaya,   mango,  custard  apple,  guava,  taro,  tomato,  capsicum,  eggplant  and  also  many  ornamental   species,  shade  trees  and  weeds.  The  adult  makes  distinctive  spiraling  patterns  when  laying   eggs  on  the  under  surface  of  the  leaf  (photo,  left);  this  gives  the  insect  its  name.    

Damage  

Damage is  caused  by  the  whitefly  piercing  the  leaf  and  sucking  the  sap;  this  leads  to  early   death  when  whitefly  numbers  are  high.  Damage  is  also  caused  by  build  up  of  sooty  mould.   Sooty  moulds  (fungi)  grow  on  the  honeydew  produced  by  the  whiteflies  and  their  nymphs  as   they  feed.  The  mould  weakens  the  leaves,  as  they  cannot  get  sunlight  for  normal  growth  

Biology and  Life  Cycle   The  eggs  are  smooth,  yellow  to  tan,  oval,  0.3  mm  long.  They  are  laid  in  a  spiral  pattern  within  a   trail  of  white  wax.  The  eggs  hatch  after  7-­‐10  days.     After  hatching,  crawlers  (nymphs  or  larvae)  move  to  the  leaf  veins  to  feed.  As  they  mature,   they  develop  waxy  tufts.  There  are  four  nymph  stages,  with  moults  between  each.  At  first,  the   nymphs  are  mobile,  but  later,  after  they  moult,  they  become  attached  to  the  leaf  and  stay   there.  The  last  nymph  stage  feeds  at  first  and  then  stops,  undergoes  internal  rearrangement,   and  then  moults  to  become  an  adult.  The  four  nymph  stages  take  20-­‐35  days  depending  on   temperature.     The  adults  (photo,  right)  live  for  about  2  weeks.  Males  are  2.2  mm  long;  females,  1.7  mm.   Adults  are  able  to  fly.  The  forewings  have  two  characteristic  dark  spots.  Egg  laying  begins  a  few   days  after  emergence.     Populations  decrease  during  cool,  rainy  days,  and  increase  again  when  days  are  warm  and  dry.  

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  inspection   Look  for  the  small  (2  mm  long),  white  and  moth-­‐like  adults  on  the  undersides  of  the  leaves.   When  populations  are  high,  look  for  the  heavy  coating  of  white,  curly  ‘wax’  produced  by  the   whitefly  nymphs.  Look  for  the  whitefly  eggs  that  are  laid  in  the  silken  spirals  produced  by  the   females.  These  spirals  are  more  noticeable  initially,  when  numbers  are  low.  They  are  also   noticeable  on  the  skin  of  fruits  and  the  surface  of  vegetables.     Look  for  the  whiteflies  at  dawn  and  dusk,  calm  times  of  the  day.  The  whiteflies  can  be  seen   flying  in  large  circular  patterns  around  the  host  plants.  They  can  be  made  to  fly  by  shaking  the   plant,  after  which  they  quickly  resettle.  

Management   NATURAL  ENEMIES   A  wasp  parasite,  Encarsia  ?haitiensis,  lays  its  eggs  in  immature  whiteflies,  killing  them.   Lacewings  and  ladybird  beetles  attack  all  stages.       When  Encarsia  is  not  present,  spiraling  whiteflies  multiply  at  a  great  rate,  producing  thousands   of  individuals  on  a  single  plant.  However,  when  the  parasite  is  present,  excellent  control  of  the   whitefly  occurs.  It  is  a  very  efficient  biocontrol  agent,  and  is  present  in  Solomon  Islands.    

CHEMICAL CONTROL   Attempts  to  control  the  pest  using  insecticides  are  not  recommended.  Spraying  with   insecticides  has  little  long-­‐term  impact  on  the  pest;  it  usually  makes  the  problem  worse  by   destroying  the  biocontrol  agents,  and  promoting  insecticide  resistance  in  the  whitefly   populations.          

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Flea Hopper  

Extension Fact  Sheet  

26

Common  name:  Flea  hopper,  Sweet  potato  flea  hopper     Scientific  name:  Halticus  sp.  (either  H.  tibialis  or  H.  minutus).   Hosts:  The  flea  hopper  has  many  host  plants,  including  crucifers  (cabbages),  cucurbits   (watermelons,  cucumbers,  pumpkins,  etc),  beans,  peanuts  as  well  as  sweet  potato.  In  Papua   New  Guinea,  H.  minutus  is  considered  a  serious  pest  of  cucumbers.      

Damage Nymphs  and  adults  of  the  flea  hopper  use  their  piercing-­‐sucking  mouthparts  to  feed  on  the   leaves.  As  a  result,  the  cells  die  and  small  whitish  spots  appear.  When  populations  are  high,   the  spots  develop  in  irregular-­‐shaped  patches  scattered  on  the  leaf  surface.  When  populations   are  very  high,  patches  join  and  the  entire  leaf  becomes  greyish-­‐white  or  silver  (photo,  left).    

Biology and  Life  Cycle   The  adult  is  black  or  dark  brown  about  2  mm  long.  It  has  long  and  slender  antennae.  The  hind   legs  are  large,  allowing  the  flea  hopper  to  jump  when  disturbed.  At  such  times,  they  often   move  quickly  to  the  underside  of  the  leaves.  Eggs  are  inserted  in  leaf  tissues;  they  are  white  to   yellow  and  less  than  1  mm  long.  In  other  species,  they  are  placed  in  feeding  punctures.       The  eggs  hatch  in  about  2  weeks,  and  the  nymphs  emerge.  The  nymphs  are  green  at  first,  later   becoming  shiny  black  as  they  moult  to  become  adults.  A  distinguishing  feature  of  the  adult   (other  than  the  long  hind  legs)  is  the  length  of  the  antennae,  which  are  longer  than  the  length   of  the  body.  The  life  cycle  takes  about  3-­‐5  weeks.    

Detection and  Inspection   Look  for  the  white  dots  on  the  top  surface  of  the  leaf,  and  black  dots  of  excreta  on  both  sides.   Look  for  the  small,  black  insects  with  large  hind  legs  that  move  rapidly  to  the  under  surface  of   the  leaf  or  jump  when  disturbed.  

  AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management   NATURAL  ENEMIES   No  natural  enemies  are  known  from  Solomon  Islands,  but,  elsewhere,  tiny  wasps  lay  their  eggs   inside  the  nymphs  and  adults.        

CHEMICAL CONTROL   • • •

When infestations  are  high,  do  not  take  planting  material  from  the  plots  in  order  to   establish  new  plantings.  Eggs  of  the  flea  hopper  might  be  taken  at  the  same  time;   In  Guam,  populations  of  the  flea  hopper  were  reduced  when  head  cabbage  was  grown   with  radish,  Chinese  cabbage  or  mustard  as  a  trap  crop;   As  Halticus  breeds  on  weeds,  wild  Ipomoea  species  in  particular,  it  is  important  to  keep   fields  free  of  weeds;  otherwise,  the  pest  will  breed  on  them  and  migrate  to  sweet   potatoes.      

CHEMICAL CONTROL   • •

Malathion is  one  of  the  recommended  chemicals  available  in  Solomon  Islands.  It  is  likely   that  synthetic  pyrethroids  will  also  be  effective.     Derris  (rotenone)  is  known  to  be  effective  against  the  flea  hopper.  A  variety  of  Derris,   brought  many  years  ago  from  Papua  New  Guinea,  is  effective  as  a  spray.  It  contains   rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for  evaluation  by   growers.  Contact  those  organisations  for  plants  to  test.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sweetpotato Hornworm  

Extension Fact  Sheet  

27

Common name:  Sweet  potato  hornworm   Scientific  name:  Agrius  convolvuli.   Hosts:  Sweet  potato  is  the  main  host,  but  it  may  also  occur  on  eggplant,  pepper,  tomato  and   legumes.    

Damage The  caterpillars  do  the  damage.  They  eat  the  leaves,  often  right  down  to  the  leaf  stalk.   Frequently,  they  are  found  at  the  shoot  tip,  preferring  young  succulent  leaves.  If  populations   are  high,  they  will  eat  all  the  leaves.  Severe  defoliation  will  affect  yield,  especially  if  it  occurs   when  plants  are  young.  Outbreaks  are  not  common;  Agrius  is  usually  under  control  by  its   natural  enemies.    

Biology and  Life  Cycle   The  greenish  eggs,  which  are  spherical,  measuring  1-­‐2  mm  diameter,  are  laid  singly  on  the   leaves  and  stems.  They  hatch  in  about  4  days,  producing  caterpillars  that  vary  from  green  to   brown,  occasionally  yellow,  with  diagonal  pale  yellow  lines  along  their  sides,  prominent  spots   and  a  distinctive  horn  (photo,  left).  They  reach  95  mm  in  length.  There  are  five  stages;  the  later   stages  do  the  most  damage,  feeding  at  night.  The  caterpillars  are  mature  in  25  days  or  less,   depending  on  the  temperature.       The  pupae  (photo,  lower  right)  are  found  in  the  soil  under  the  plants.  They  are  reddish  brown   with  a  prominent  proboscis  or  "trunk",  which  is  curved  downward  and  looks  like  a  jug  handle.     Adults  emerge  from  the  pupae  in  25  days  or  less;  they  are  large  greyish-­‐brown  hawk   moths,  with  black  lines  on  the  wings  and  pink  markings  on  the  abdomen  (photo,  above   right).  The  wingspan  is  8-­‐12  cm.  

  AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Inspection and  Detection     Look  for  large  holes  in  the  leaves,  and  faeces  (droppings)  of  the  caterpillar  on  the  young   leaves.  The  size  of  the  mature  caterpillars  and  the  horn  are  distinguishing  features  of  this   species.  

Management NATURAL  ENEMIES   Populations  of  the  sweet  potato  hornworm  are  usually  kept  in  check  by  a  number  of   parasitoids  and  predators.  Among  the  important  egg  parasites  are  minute  wasps,   Trichogramma  spp.,  while  Sycanus  sp.,  a  large  reduviid  (predatory  insect),  and  a  tachinid  fly   feed  on  the  larvae.    

CHEMICAL CONTROL   • •  

Handpicking of  the  larvae  can  be  quite  effective  in  small  areas;   If  there  are  large  numbers,  allow  chickens  into  the  garden.    

CHEMICAL CONTROL   Pesticides  are  not  recommended  as  they  disrupt  the  action  of  the  egg  and  larval  parasites.  The   hornworm  is  usually  controlled  by  natural  enemies,  and  pesticides  may  kill  these  and  make   matters  worse.       If  they  are  needed,  it  is  best  to  use  synthetic  products  that  contain  disease-­‐causing  organisms,   such  as  spinosad  (Success)  and  Bt  -­‐  Bacillus  thuringiensis.  Spinosad  and  Bt  are  sold  sometimes   in  Honiara.     A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.     Preparations  using  neem  seed  extract  can  be  used;  see  the  Kastom  Gaden  Association  for   seedlings.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sweetpotato Leaf  Folder  

Extension Fact  Sheet  

28

Common name:  Green  leaf  folder1   Scientific  name:  Herpetogramma  hipponalis.   Hosts:  Sweetpotato  (Ipomoea  batatas)  is  a  major  host  in  Solomon  Islands.  The  caterpillars  also   occur  on  other  Ipomoea  species  and  Mikania  cordata.  

Damage The  caterpillar  does  the  damage.  It  folds  the  leaf,  holding  the  folded  parts  together  with   webbing.  The  young  caterpillars  eat  the  surface  of  the  leaf  (photo,  above);  later,  when  larger,   they  eat  through  the  leaf  creating  small  windows.  Often,  the  damage  looks  severe  with  all  the   youngest  leaves  folded,  and  they  may  turn  brown,  but  there  is  no  information  on  the  effect  of   leaf  damage  on  storage  root  yield.  

Biology and  Life  Cycle   The  moth  (photo,  right)  lays  eggs  singly  or  in   groups  on  the  upper  surface  of  the  leaf  near  the   midrib.  About  90  eggs  are  laid  in  a  day.  The  eggs   are  shiny  green,  oblong,  and  covered  with  a   scale-­‐like  gelatinous  material.  The  eggs  hatch   after  3–5  days  and  the  caterpillars  are  at  first   greenish-­‐yellow,  turning  darker  green  with  age.   They  have  a  dark  brown  head.  The  caterpillars   moult  four  times  over  15-­‐30  days  and  when  matures  are  about  13  mm  long.  Only  the  larger   caterpillars  fold  the  leaves.  In  most  cases,  there  is  one  caterpillar  per  leaf  fold.     1

Information on this pest comes from two sources: a) T Ames, NEJM Smit, AR Braun, JN O’Sullivan , LG Skoglund (1997) Sweet potato: Major pests, diseases, and nutritional disorders. International Potato Center (CIP), Apartado 1558, Lima 12, Peru; and b) Sweet potato Diagnotes: A Diagnostic Key and Information Tool for Sweet potato Problems. http://www.lucidcentral.org/keys/sweetpotato/key/Sweetpotato%20Diagnotes/media/html/FrontPage/FrontPage.htm

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   The  caterpillars  turn  into  yellowish-­‐white  pupae,  which  later  turn  reddish  brown.  The  adults   emerge  from  the  pupae  in  4–8  days;  they  are  yellowish-­‐brown  with  dark  brown  zigzags   markings  on  the  wings  (photo,  right).  The  female  moth  lives  for  about  3  days.  

Detection and  Inspection   Look  for  folded  leaves,  unfold  them  and  look  for  caterpillars  and  faecal  pellets  (droppings).   Look  at  the  surface  of  the  leaf;  you  should  see  small  windows  between  the  veins  caused  by  the   caterpillar  eating  the  top  surface  of  the  leaf  (photo,  above).  Webbing  may  be  present.  The   adult  moth  is  brown  with  zig-­‐zag  markings  on  the  wings.  

Management   NATURAL  ENEMIES   Tiny  (braconid)  wasps  are  common  and  these  control  the  leaf  folder  populations.  They  are   seen  rarely  as  they  are  so  small.  Earwigs  and  other  predators  are  also  important  in  maintaining   natural  control.      

CULTURAL CONTROL   •

The use  of  uninfested  planting  material  is  an  effective  means  of  reducing  the  incidence  of   leaf  folders.  Take  care  when  taking  cuttings  for  replanting;  remove  folded  leaves  or  choose   only  those  cuttings  without  them;   If  possible,  do  not  plant  new  gardens  next  those  that  have  high  infestations  of  leaf  folder,   otherwise  the  moths  will  easily  fly  to  the  new  gardens.  

CHEMICAL CONTROL   The  leaf  folder  is  usually  under  natural  control  by  its  enemies.  Pesticides  are  rarely  needed.  If   they  are,  then  use  either  pyrethrum  or  a  synthetic  pyrethroid,  such  as  permethrin  or  lambda   cyhalothrin.  Another  good  choice  is  Bacillus  thuringiensis  kurstaki,  known  as  Bt;  this  contains  a   bacterium  that  produces  a  toxin  that  kills  the  caterpillars.  A  wetting  agent  will  be  needed  to   ensure  that  the  chemical  reaches  the  caterpillars  in  the  leaf  folds.     A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.     Preparations  using  neem  seed  extract  can  be  used;  see  the  Kastom  Gaden  Association  for   seedlings.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sweetpotato Weevil  

Extension Fact  Sheet  

29

Common name:  Sweet  potato  weevil                                                                   Scientific  name:  Cylas  formicarius.   Hosts:  Sweet  potato  (Ipomoea  batatas)  and  many  types  of  morning  glory.    

Damage Damage  is  done  by  the  adult  beetles  (photo,  left)  and  grubs  (photo,  right).  The  adults  feed  on   the  buds,  leaves,  vines  and  storage  roots.  However,  grubs  cause  most  damage  by  tunnelling   through  the  stems  and  storage  roots.    

Biology and  Life  Cycle   Female  beetles  lay  eggs  singly  in  the  base  of  the  vines,  or  crawl  through  cracks  in  the  soil  to   reach  the  storage  roots.  The  eggs  are  white,  oval,  and  about  0.5  mm  long.  They  are  sealed  in   with  a  protective  grey  faecal  plug.  Several  hundred  eggs  are  laid  over  a  lifespan  of  about  4   months.       The  grubs  or  larvae  are  legless,  white,  with  a  brown  head  and  reddish-­‐brown  gut.  At  maturity,   the  grubs  are  up  to  8  mm  long;  they  then  pupate.  Pupae  are  creamy  white,  up  to  6  mm  long.   This  stage  lasts  about  a  week.  After  coming  out  of  the  pupa,  the  adult  beetle  stays  in  the   tunnel  for  about  a  day  before  cutting  through  to  the  outside.     Adult  weevils  are  small  and  ant-­‐like  (photo,  left).  They  are  5-­‐7  mm  long,  with  a  smooth  and   slender  body  and  snout.  Their  head  and  rear  are  metallic  blue  or  black,  and  their  middle,  legs   and  feelers  are  red.  The  full  lifecycle  takes  just  over  a  month.  

Detection and  Inspection     Look  at  the  base  of  the  plant  for  small  holes  and  damage  to  the  stem.  Break  the  stem  to  see  if   there  are  tunnels,  rot  and  larvae.  Dig  up  a  storage  root  and  look  for  damage  to  the  skin,  and   feeding  tunnels  of  the  larvae  inside.  Adult  beetles  are  most  active  at  night,  but  can  sometimes   be  seen  on  plants  during  the  day.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management NATURAL  ENEMIES   Predatory  ants,  beetles,  spiders  and  earwigs  attack  adult  weevils.  Some  tiny  wasps  attack   them.  They  also  become  infected  by  Beauveria,  a  fungus.  Bacteria  and  nematodes  kill  the   grubs.      

CHEMICAL CONTROL   • •

• •

Crop rotation:  Grow  sweet  potatoes  in  a  field  only  once  every  3-­‐4  years.  Avoid  planting   sweet  potatoes  in  the  same  area  2  years  in  a  row,  and  plant  well  away  from  infested  crops;   Hill  up  and  mulch:  Weevils  usually  access  roots  by  cracks  in  the  soil.  Prevent  the  soil  from   cracking  by  hilling  soil  around  the  plant.  Also,  prevent  cracking  by  spreading  mulch  to  keep   the  soil  moist.  Plant  cuttings  deep  in  the  soil,  use  deep-­‐rooted  varieties,  and  harvest  the   crop  as  soon  as  it  has  developed  sizeable  roots;   Sanitation:  Destroy  any  crop  residues  left  in  the  field  after  harvest,  since  weevils  survive  in   the  roots  and  stems.     Selection  of  planting  material:  Select  clean  cuttings  (25-­‐30  cm  long)  from  fresh  young   growth  to  reduce  the  spread  of  weevils.    

BIOLOGICAL CONTROL   The  fungus,  Beauveria  bassiana,  is  produced  in  large  quantities  and  used  intensively  for  the   control  of  sweet  potato  weevil  in  Cuba.  Sprays  of  the  fungus  have  largely  replaced  the  use  of   chemical  insecticides.  Also  in  Cuba,  predatory  ants  (Pheidole  megacephala,  the  big-­‐headed   ant)  have  also  been  used  effectively  to  control  weevils.  Research  on  both  these  potential   biological  control  organisms  is  being  done  in  PNG.    

CHEMICAL CONTROL   Before  planting:  Treat  vine  cuttings  with  insecticides  to  kill  weevils  and  prevent  infestation   in  new  plantings.  There  are  no  recommended  pesticides  for  use  in  Solomon  Islands.  This  is   a  better  use  of  insecticides  than  post-­‐plant  applications,  especially  if  combined  with  proper   sanitation  and  the  other  measures  listed  under  cultural  control;   • Inspect  the  crop  regularly,  at  least  once  a  week:  Check  the  base  of  the  vines,  looking  for   damage  and  holes;   • Post-­‐plant  application:     o Use  the  male  pheromone  to  monitor  weevil  populations.  Spray  with  insecticide  (e.g.   bifenthrin)  when  numbers  reach  a  pre-­‐determined  threshold  level.  (A  pheromone  is  a   chemical  released  by  insects  to  bring  the  sexes  together);   o Alternatively,  spray  routinely  with  bifenthrin,  every  14  days.   These  treatments  would  only  be  suitable  for  commercial  growers.  See  your  MAL  extension   officer  for  details.     •

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Taro Beetles  

Extension Fact  Sheet  

30

Common name:  Taro  beetles   Scientific  names:  Papuana  species.  There  are  18  species  in  Papua  New  Guinea,  11  of  which   damage  taro;  there  are  six  species  in  Solomon  Islands.  Common  species  are:  Papuana   woodlarkiana,  Papuana  huebneri,  Papuana  trinodosa,  Papuana  biroi,  Eucopidocaulus   tridentipes  and  Papuana  szentivanyi.   Hosts:  Common  hosts  of  Papuana  beetles  are  seedlings  of  oil  palm  and  coconut,  Alocasia   (giant  taro),  banana,  Cryrtosperma  (giant  swamp  taro),  sugarcane,  Pandanus  and  taro.      

Damage Adult  beetles  do  the  damage  by  burrowing  into  the  underground  parts  of  their  hosts.  Oil  palm   and  coconut  seedlings,  and  taro  plants  wilt  and  die  when  the  tunnels  reach  the  growing  point.   More  commonly,  plants  remain  alive,  but  grow  poorly.  Holes  bored  in  the  corms  of  taro  make   them  unfit  for  market,  and  where  damage  is  considerable  they  are  not  even  fit  for  home  use.       Estimates  of  the  amount  of  damage  are  hard  to  come  by,  but  in  Papua  New  Guinea  it  is  put  at   about  15%,  with  losses  as  high  as  80%  in  individual  gardens.  In  many  parts  of  Solomon  Islands,   taro  is  very  difficult  to  grow  because  of  Papuana  beetles,  and  they  are  one  of  the  reasons  why   farmers  have  abandoned  this  crop.  This  is  serious,  because  loss  of  taro  means  a  loss  of  genetic   diversity,  and  this  may  impact  food  security.  It  may  also  undermine  cultural  traditions,  many  of   which  are  dependent  on  taro.  

Biology and  Life  Cycle   The  adult  is  a  shiny  black  beetle,  15-­‐25  mm  long.  The  beetles  have  horns  on  the  head,  but  the   number  and  size  differs  among  species.  Those  of  the  male  are  generally  larger.  Eggs  are  laid   about  7  weeks  after  the  female  emerges  from  the  soil.  The  eggs  are  laid  singly;  they  are  white,   oval  and  2-­‐3  mm  long.  Grubs  emerge  after  about  2  weeks.  These  are  white,  and  ‘C’  shaped  at   rest.  They  moult  three  times  and  when  mature  are  25-­‐40  mm  long.  The  grubs  last  about  90   days  before  they  pupate  for  3-­‐4  weeks  and  the  adult  emerges.  The  entire  life  cycle  takes  4-­‐5   months.     Male  beetles  are  less  mobile:  they  colonise  the  taro  corms,  awaiting  the  arrival  of  the  female.   After  mating,  the  female  flies  to  find  a  breeding  site,  usually  places  with  decaying  organic   matter,  e.g.,  rotten  logs/stumps,  manure,  saw  dust,  along  river  banks  and  in  the  fibrous  roots  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   of  grasses.  Each  female  lays  up  to  300  eggs  during  a  lifespan  of  about  20  months.  The  adults   are  capable  of  flying  up  to  a  kilometre,  and  they  are  attracted  to  lights.     When  the  forest  is  disturbed,  for  instance  due  to  logging  or  cyclones,  taro  beetles  are  common   in  taro  gardens.  In  the  forest,  ferns  (Angiopteris  species)  are  a  common  host.    

Detection and  Inspection   Look  for  young  oil  palm,  coconut  and  taro  plants  that  are  wilting  and  ,  if  found,  check  if   Papuana  beetles  are  present  by  pulling  the  plants  out  of  the  ground.  More  sophisticated   methods  include  the  use  of  light  traps  and  sampling  of  breeding  sites  (compost  heaps,   sawdust,  rotting  logs)  and  wild  hosts,  such  as  grasses  (Paspalum  species  and  Brachiaria   mutica),  bananas  and  sugarcane.    

Management   NATURAL  ENEMIES   Several  natural  enemies  have  been  recorded,  including  the  fungus  Metarhizium,  a  tachinid  fly   and  the  cane  toad,  but  none  are  considered  effective  in  controlling  populations  sufficiently   well  to  stop  corm  damage.        

CHEMICAL CONTROL   Several  cultural  control  measures  have  been  suggested,  including  crop  rotation,  clean  planting   material  (i.e.,  free  from  soil),  and  destruction  of  breeding  sites  near  gardens,  but  these  are   impractical,  and  are  unlikely  to  be  effective,  even  if  farmers  tried  to  implement  them.    

BIOLOGICAL CONTROL   Although  much  work  has  been  done  using  the  fungus  Metarhizium  anisopliae,  and  it  has  been   shown  to  work  under  experimental  conditions,  as  yet  there  is  no  practical  recommendation  for   farmers.  It  is  difficult  for  farmers  to  maintain  stocks  of  the  fungus,  which  has  to  be  grown  on,   for  example,  rice  grains  and  applied  to  each  planting  hole  as  well  as  likely  breeding  sites.     The  virus  that  infects  Oryctes  rhinoceros,  the  dynastid  beetle  of  coconuts,  has  been  tried   against  Papuana,  but  without  success.        

CHEMICAL CONTROL   Use  imidacloprid  (sold  under  the  trade  name  of  Confidor),  or  a  pyrethroid  (Mustang);  both  are   effective  in  controlling  Papuana  beetles  in  Fiji,  and  also  in  trials  in  Solomon  Islands.  Confidor  is   available  in  Honiara.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cluster Caterpillar    

Extension Fact  Sheet  

31

Common names:  Taro  cluster  caterpillar,  Taro  armyworm   Scientific  name:  Spodoptera  litura.   Hosts:  Taro  cluster  caterpillar  has  a  wide  host  range,  attacking  many  vegetables  -­‐  cabbages,   tomatoes,  okra,  chilli,  cassava,  corn,  sweet  potato,  rice,  eggplant,  watercress  and,  especially,   taro.  

Damage It  is  the  caterpillar  (or  larva)  that  does  the  damage.  The  young  caterpillars  radiate  from  the  egg   masses  (photo,  lower  left),  stripping  the  leaf  surface  and  eating  the  leaf  between  the  veins   (photo,  upper  left).  Later,  they  become  solitary  and  eat  all  the  leaf,  including  the  petioles.   Mostly,  they  feed  at  night.  Normally,  the  caterpillars  are  well  controlled  by  their  natural   enemies,  but  occasionally,  especially  after  natural  disasters  or  where  gardens  are  isolated,   outbreaks  occur,  and  these  can  be  severe.  

Biology and  Life  Cycle   The  cream  to  golden-­‐brown  eggs  are  laid  in  masses  (4-­‐7  mm  diameter)  covered  with  hairy   scales  from  the  tip  of  the  abdomen  of  the  female.  After  hatching,  the  caterpillars  stay  together   (hence  the  name  ‘cluster  caterpillar’).  They  vary  in  colour:  pale  green  at  first,  then  later,  dark   green  to  brown  (photo,  upper  right).  There  have  bright  yellow  stripes  along  the  top  of  their   body.  The  caterpillars  moult  five  times  during  15-­‐30  days,  depending  on  the  temperature.   Afterwards,  they  pupate  in  the  soil  for  7-­‐10  days.       If  the  eggs  are  laid  on  a  plant  that  is  inedible,  the  young  caterpillars  drop  silken  threads  and  are   carried  on  the  wind  to  other  potential  hosts.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   The  body  of  the  moth  is  grey-­‐brown,  15-­‐20  mm  long,  with  a  wingspan  of  30-­‐40  mm  (photo,   lower  right).  The  forewings  are  grey  to  reddish  brown  with  a  strongly  variegated  pattern.  The   hind  wings  are  greyish-­‐white  with  grey  margins.  The  moths  can  fly  up  to  1.5  km  a  night.  They   are  attracted  to  light.  

Detection and  Inspection   Look  for  the  egg  masses:  they  are  relatively  easily  seen  against  the  dark  green  of  the  leaves.   Look  for  the  ‘scratch’  marks  left  by  the  newly  hatched  larvae  on  the  leaf  surface.  The  older   caterpillars  are  night-­‐feeders.  They  chew  large  areas  of  the  leaf  and,  when  numerous,  can   defoliate  a  crop.  In  such  cases,  the  larvae  migrate  in  large  groups  from  one  field  to  another  in   search  of  food  (hence  the  name  ‘armyworm’).  

Management NATURAL  ENEMIES   These  include  egg  parasites  -­‐  Telenomus  nawaii;  and  larval  parasites  -­‐  Apanteles  marginiventris   (wasp),  Peribaea  orbata  (a  fly),  Chelonus  sp.  (wasp),  Palexorista  sp.  (a  fly),  and  many  more.      

CULTURAL CONTROL   •

• •

Remove leaves  with  egg  masses  or  young  caterpillars  –  this  is  an  effective  control  measure.   In  most  cases  the  entire  leaf  does  not  have  to  be  destroyed,  only  that  part  containing  the   eggs  or  caterpillars;   Destroy  the  eggs  and/or  caterpillars  as  soon  as  they  are  seen  by  rubbing  them  with  a  hand   or  another  leaf;   If  there  are  many  caterpillars,  and  damage  looks  likely,  let  chickens  into  the  garden.    

CHEMICAL CONTROL   Pesticides  are  not  normally  recommended  for  the  control  of  this  moth  on  taro.  They  are  only   needed  when  the  natural  enemies  have  been  destroyed  by  cyclones,  droughts,  or  when   plantings  are  in  isolated  places.  In  these  situations,  it  is  best  to  use  natural  insecticides,  such  as   chilli,  derris,  neem,  pyrethrum,  or  those  containing  bacteria,  such  as  spinosad  (Success)  and  Bt   –  Bacillus  thuringiensis  kurstaki.  Spinosad  and  Bt  are  sometimes  sold  in  Honiara.     A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.     Preparations  using  neem  seed  extract  can  be  used;  see  the  Kastom  Gaden  Association  for   seedlings.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Taro Hornworm    

Extension Fact  Sheet  

32

Common name:  Taro  hornworm                                                                                     Scientific  name:  Hippotion  celerio.   Hosts:  It  is  recorded  from  taro,  sweet  potato  and  noni  (Morinda  sp.)    

Damage The  caterpillars  do  the  damage.  They  eat  the  leaves,  leaving  only  the  main  veins  (photo,  above   left).  Sometimes  even  these  are  eaten  and  only  the  petioles  are  left.  Outbreaks  are  not   common  as  the  caterpillars  are  under  control  from  natural  enemies;  otherwise,  the  caterpillars   can  be  very  damaging.    

Biology and  Life  Cycle   The  eggs  are  laid  singly  on  both  sides  of  the  leaf  and  on  the  petioles.  They  vary  from  round  to   oval,  and  from  clear  to  bluish-­‐green.  Just  before  the  emergence  of  the  caterpillars  they  are   green-­‐yellow.  The  caterpillars  moult  four  times:  at  first   they  are  pale  yellow,  then,  as  they  age,  they  become   green  and  dark  brown  (photo,  above  right).  Some  remain   green.  The  eyespots  and  a  yellow  line  running  almost  the   entire  length  of  the  caterpillar  develop  after  the  first   moult.  When  mature,  the  caterpillars  are  80-­‐90  mm  long.   At  this  stage,  they  move  to  the  soil,  form  a  cocoon  or  cell   in  the  leaf  litter  or  just  below  the  soil,  and  pupate.  The   pupae  are  grey-­‐brown,  45-­‐50  mm  long,  with  dark  brown   specks.  This  period  lasts  15-­‐18  days.     Adults  have  wingspans  of  40-­‐90  mm;  they  are  streamlined,  with  large  heads  and  eyes  (photo,   above).  The  forewings  are  long,  narrow  and  much  larger  than  the  hind  wings.  The  forewings   have  an  oblique  silver  stripe  across  a  generally  grey  background,  while  the  hind  wings  may   have  pink  or  brown  and  black  areas.  At  rest,  the  wings  are  ‘tented’  over  the  body.  The  moths   are  capable  of  flying  long  distances  and  are  attracted  to  light.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   The  damage  done  to  taro  is  characteristic  of  this  hornworm.  Look  for  the  way  that  the  leaves   are  eaten  between  the  veins.  Also,  the  caterpillars  can  be  found  on  the  leaves  during  the  day,   especially  on  the  underside.  Look  for  a  large  caterpillar  with  eyespots  at  the  front  end,  with  a   line  along  the  sides,  and  a  horn  at  the  end.      

Management NATURAL  ENEMIES   These  include  egg  parasites  –  Trichogramma  sp.  (a  wasp);  and  larval  parasites  Palexorista  sp.  (a   fly),  Snellenius  hippotionus  (a  wasp),  and  there  are  probably  many  more.  The  cane  toad  may   also  feed  on  the  larvae.    

CULTURAL CONTROL   The  caterpillars  are  large,  and  handpicking  is  an  option  if  the  numbers  and  area  of  infestation   are  small.  If  they  are  large,  chickens  are  often  a  good  way  of  managing  outbreaks.    

CHEMICAL CONTROL   Pesticides  are  not  recommended  as  they  disrupt  the  activities  of  the  egg  and  larval  parasites.   Natural  enemies  usually  control  the  hornworm.  If  pesticides  are  used  they  will  kill  them  and   make  matters  worse.     If  they  are  needed,  it  is  best  to  use  natural  products,  such  as  chilli,  derris,  neem,  pyrethrum,  or   those  synthetic  products  containing  bacteria,  such  as  spinosad  (Success)  and  Bt  –  Bacillus   thuringiensis.  Spinosad  and  Bt  are  sometimes  available  in  Honiara.     A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.     Preparations  using  neem  seed  extract  can  be  used;  see  the  Kastom  Gaden  Association  for   seedlings.          

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cucumber Moth    

Extension Fact  Sheet  

33

Common names:  Cucumber  moth.  Other  common  names  include,  Melon  moth,  Pumpkin   caterpillar,  Cucurbit  caterpillar  and  Watermelon  ‘worm’   Scientific  name:  Diaphania  indica.   Hosts:  Cucurbits  are  hots;  common  cucurbits  are  watermelon,  cucumber,  melon,  pumpkin  and   snake  gourd.      

Damage The  caterpillars  do  the  damage.  After  hatching,  they  roll  the  leaves  with  silken  threads  and  eat   the  leaves  between  the  veins.  They  also  attack  the  flowers  and  reduce  the  number  of  fruits   set.  Young  fruits  are  also  attacked:  the  caterpillars  damage  the  skin  and  cause  the  fruits  to  rot.  

Biology and  Life  Cycle   The  eggs  are  oval,  about  0.7  mm  long  and  0.4  mm  wide,  thin  walled  and  whitish.  They  are  laid   in  small  groups  on  the  growing  parts  of  the  shoot,  usually  on  the  underside  of  the  leaves  or  on   buds  and  flowers.       The  eggs  hatch  and  the  caterpillars  emerge.  They  are  almost  clear,  but  soon  become  green.   Large  caterpillars  have  two  white  lines  along  the  back  (photo,  left).  When  fully  grown,  they  are   about  20  mm  long:  some  may  be  smaller,  some  larger.       After  a  while,  the  caterpillars  turn  into  pupae,  green  at  first  then  brown.  The  pupae  are  in  folds   of  the  leaves.  They  are  about  12  mm  long  and  3  mm  wide.  The  adults  hatch  from  the  pupae   after  about  8-­‐12  days.       The  adult  is  very  obvious  (photo,  right).  The  wings  are  white  with  a  wide  brown  border.  When   the  wings  are  spread,  they  are  about  25  mm  wide.  At  the  end  of  the  body  is  a  group  of  hairs,   rather  like  a  brush.  The  females  wiggle  this  brush,  possibly  to  send  out  a  chemical  to  attract   the  males.  The  life  cycle  from  egg  to  adult  is  about  25  days.      

Detection  and  Inspection   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Look  at  the  young  leaves:  look  for  leaves  where  the  veins  are  still  there,  but  the  parts  between   have  been  eaten.  Inspect  the  young  fruits:  look  for  signs  of  caterpillar  damage.  Look  for   caterpillar  faeces  or  droppings.  

Management NATURAL  ENEMIES   • • •

Tiny wasps  that  are  hard  to  see  with  the  naked  eye  attack  the  caterpillars;     Lacewings  eat  the  eggs;   It  is  important  to  think  about  these  natural  enemies  when  considering  how  to  control   Diaphania.  If  chemicals  are  used,  it  is  best  to  choose  those  that  do  not  kill  these  natural   enemies.  Preferably,  use  chemicals  that  are  allowed  under  organic  vegetable  production  -­‐   see  below.  

CULTURAL CONTROL   •

Make regular  inspections  of  the  crop,  at  least  once  a  week.  Check  the  young  leaves,   looking  for  those  that  are  stuck  together  and  those  where  only  the  veins  are  left.  Look  for   faeces  on  the  leaves.  They  are  the  signs  that  the  caterpillars  are  present;   Hand  picking  should  be  the  first  method  of  control.  Look  for  rolled  leaves:  remove  them,   or  squeeze  and  kill  the  caterpillars  inside.  Check  the  flowers  and  the  fruits  for  damage.  If  it   is  severe,  consider  using  chemicals.  But  consider  carefully  which  ones  to  use.    

CHEMICAL CONTROL   Orthene  (acephate)  is  being  used  by  many  farmers  for  the  control  of  this  worm,  but  it  is  not   the  best  choice.  Orthene  is  good  for  sucking  insects  as  it  has  systemic  activity;  that  means  it   enters  the  plant  and  moves  inside  it.  It  will  kill  the  caterpillars,  but  it  will  kill  all  other  insects,   too,  whether  they  are  good  or  bad.       The  following  alternatives,  made  from  bacteria,  are  recommended:   • Spinosad,  also  known  as  Success;   • Bacillus  thuringiensis  kurstaki,  also  known  as  Bt.     Pyrethrum  and  derris  insecticides  can  also  be  used;  these,  too,  are  made  from  natural   products.  Pyrethrum  comes  from  a  member  of  the  daisy  family  and  derris  is  a  shrubby   legume.  They  are  fast  acting  against  insects  and  less  harmful  to  the  environment  compared  to   many  synthetic  (commercial)  products.  They  are  broken  down  quite  quickly  by  sunlight.  BUT   they  will  kill  natural  enemies  of  Diaphania.       A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.     Preparations  using  neem  seed  extract  can  be  used;  see  the  Kastom  Gaden  Association  for   seedlings.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Puccinia Peanut  Rust  

Extension Fact  Sheet  

34

Common  name:  Peanut  rust   Scientific  name:  Puccinia  arachidus.   Hosts:  Peanuts,  and  some  other  plants  belonging  to  the  genus  Arachis.    

Damage Infection  causes  leaves  to  turn  yellow  (photo,  left),  dry,  curl  and  drop.  It  is  not  known  what   losses  occurs  in  Solomon  Islands,  but  it  is  likely  that  yields  are  reduced  by  50%,  probably  much   more.  Infected  plants  mature  2-­‐3  weeks  early.     Once  infections  occur,  rust  develops  very  rapidly,  faster  than  the  diseases  caused  by  early  and   late  leaf  spots  (see  Fact  Sheet  No.  36).  

Biology and  Life  Cycle   The  rust  infects  leaves,  petioles,  pegs  (the  shoots  that  grow  into  the  ground)  and  stems.  On   the  leaves,  the  spots  are  at  first  yellow,  rapidly  turning  orange  and  then  red-­‐brown  as  masses   of  spores  develop  and  break  through  the  leaf  surface  (photo,  right).  The  lower  surface   produces  the  most  spores.       The  spread  of  rust  depends  on  wind  to  disperse  the  spores,  and  humidity  to  provide  conditions   for  infection  at  the  leaf  surface.  

Detection and  inspection   Inspect  plants  regularly,  at  least  once  a  week,  looking  for  the  red-­‐orange  spots.    

Management CULTURAL  CONTROL   Cultural  control  is  important,  but  note  that  rusts  only  survive  in  living  plants;  they  do  not   survive  in  crop  remains  or  in  the  soil.  Spores  are  spread  in  moist,  warm  air,  and  periods  of       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   cloudy  wet  weather  favour  outbreaks  of  the  disease;  these  are  common  conditions  in  Solomon   Islands.       The  following  should  be  done:   • Remove  any  volunteer  plants  from  the  last  crop;   • Plant  new  crops  as  far  away  as  possible  from  older  crops,  especially  those  with  rust   infections;   • If  it  is  not  possible  to  avoid  planting  near  older  crops,  do  not  plant  down  wind  from  them;   otherwise,  spores  will  easily  spread  to  the  new  crops.    

RESISTANT VARIETIES   There  are  varieties  that  differ  in  resistance  to  rust,  but  there  is  no  information  about  the   resistance  of  those  grown  in  Solomon  Islands.  Varieties  from  Papua  New  Guinea  are  under  test   in  Solomon  Islands.  See  MAL  for  information.    

CHEMICAL CONTROL   • •

• •

Carry out  regular  inspections;   Begin  to  spray  as  soon  as  rust  spots  are  seen,  even  if  they  appear  on  only  one  or  a  few   plants.  Spray  at  regular  intervals:  10-­‐14  days  is  best,  continuing  until  14  days  before   harvest;   Spray  more  often  if  the  first  treatment  is  late,  and  there  are  many  plants  with  rust  spots.  In   most  cases,  spraying  should  begin  no  later  than  30-­‐35  days  after  planting;   Use  chlorothalonil  (the  trade  name  is  Bravo).  It  is  effective  against  rust,  and  also  leaf  spot   diseases.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Rats

Extension Fact  Sheet  

35

Species  present:  Polynesian  rat  (Rattus  exulans),  the  Ship  rat  (R.  rattus),  and  the  Brown  rat  (R.   norvegicus).  None  of  these  species  are  native  to  Solomon  Islands.  

Description Polynesian  rat:   • • • • •

Slender body,  pointed  snout,  large  ears;  relatively  small,  delicate  feet;   Red-­‐brown  back  and  white  underneath;   Body  weight  40-­‐80  g;  up  to  15  cm  long  -­‐  tip  of  the  nose  to  the  base  of  the  tail;   Tail  has  prominent  fine,  scaly  rings,  about  the  same  length  as  the  head  and  body;   Females  have  8  nipples.  

Ship rat:   • • • • •

Slender body,  large  hairless  ears;   Grey-­‐brown  on  the  back;  either  a  similar  colour  or  creamish-­‐white  underneath  or  all  black;   Body  weight  120-­‐160  g,  but  it  can  exceed  200  g;  up  to  22  cm;   Tail  is  one  colour;  it  is  always  longer  than  the  head  and  body  length  combined;   Females  have  10  nipples.  

Brown rat:   • • • • •

Small ears  -­‐  which  usually  do  not  cover  the  eyes  when  pulled  forward;   Brown  on  the  back,  pale  grey  beneath;   Body  weight  150–300  g,  but  can  reach  500  g;  up  to  39  cm  long;   Tail  is  shorter  than  the  head-­‐body  length;   Females  have  12  nipples.  

Damage All  three  damage  crops,  and  are  a  threat  to  the  country’s  biodiversity.  Apart  from  fruits,  grains   and  other  plant  material,  these  rats  eat  insects,  reptiles  and  young  birds.  They  are  pests  of   agriculture  crops,  including  rice,  maize,  sugarcane,  coconut,  cacao,  pineapple,  peanuts  and   root  crops.  They  eat  stored  foods,  and  spoil  them  by  urinating  and  defecating  on  them.  Rats   carry  a  scrub  typhus  in  Santa  Cruz,  which  is  transmitted  via  the  fleas  that  they  host.       Note,  damage  in  coconuts  is  not  directly  related  to  the  number  damaged;  it  occurs  early  and   palms  compensate  for  about  50%  of  the  loss.  In  cocoa,  this  is  not  the  case  as  damage  occurs   when  pods  are  near  maturity.  

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Habitat All  three  species  can  be  found  in  grasslands,  scrub,  forests  and  urban  areas.  The  Polynesian  rat   does  not  burrow,  but  digs  small  holes  and  nests  mainly  on  the  ground.  The  Brown  rat  makes   burrows  and  nests  underground.  The  Polynesian  and  Ship  rat  climb,  the  Brown  rat  rarely  does.   Ship  rats  often  nest  in  trees.  The  Brown  rat  swims  well,  and  favours  wet  habitats.  In  Solomon   Islands,  it  is  probably  more  common  in  ports  and  towns  than  village  gardens.  

Life Cycle   If  food  is  available,  rats  breed.  Females  can  reproduce  several  times  a  year.  Sexual  maturity  is   2-­‐3  months,  gestation  (period  between  fertilization  and  birth)  is  21-­‐24  days  and  average  litter   size  is  6-­‐10.  Life  expectancy  is  12-­‐15  months.    

Management CULTURAL  CONTROL   • •

Band coconut  trunks  with  an  aluminium  strip  (30  cm  wide  at  least  2.5  m  from  the  ground)   to  reduce  rat  damage  in  plantations;   DO  NOT  leave  household  waste  for  rats  to  eat;  otherwise,  populations  will  remain  high.   Good  sanitary  practices  are  essential  in  villages  and  towns.  

PHYSICAL CONTROL   Snap-­‐traps  are  efficient,  especially  if  they  are  left  with  food  but  unset  for  a  few  days  before   being  set  properly.  Bait  shyness  can  be  a  problem.  The  traps  should  be  put  where  children  and   pets  cannot  get  to  them.    

CHEMICAL CONTROL   • •

• •

Use anticoagulants  (prevent  blood  clotting),  warfarin  and  brodifacoum  made  into  baits   with  coconut,  wheat  or  maize.  Warfarin  is  less  toxic;   Prevent  baits  from  being  taken  by  other  animals,  cats  and  dogs  in  particular,  and  also  by   birds.  Put  baits  in  pipes  or  bamboo  sections.  Ideally,  collect  baits  in  the  morning  and  put   them  out  in  the  evening.  Resistance  to  warfarin  is  known;   Make  warfarin  (0.025-­‐0.05%  w/v)  into  waterproof  blocks  (80  g)  with  paraffin  wax  and  bait,   and  tie  to  branches  of  trees.  Place  25-­‐30  sites  per  ha;   Use  brodifacoum  (0.005%  w/v)  as  ready-­‐made  pellets  containing  bait.  Less  is  needed  per   station.  Read  the  label  or  seek  expert  advice.    

Gliricidia  (the  shade  tree).  Pound  young  leaves  and  mix  with  cooked  rice,  maize  or  other  bait.   Bacteria  convert  chemicals  in  the  leaves  to  substances  similar  to  brodifacoum.  These  are  less   toxic  than  brodifacoum,  so  larger  amounts  must  be  eaten.  Try  using  the  bark.  Change  the  bait   daily,  and  protect  from  pets.     In  Reef  Islands,  the  white  inner  flesh  of  Barringonia  asiatica  fruits  (4-­‐sided  on  trees  along   seashore)  are  scraped,  added  to  cooked  rice  or  shredded  coconut,  and  used  as  a  rat  poison.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Peanut Leaf  Spots  

Extension Fact  Sheet  

36

Common  name:  Peanut  leaf  spot   Scientific  names:  Mycosphaerella  arachidis  (Early  leaf  spot)  and  M.  berkeleyi  (Late  leaf  spot).   These  are  the  names  of  the  fungus  that  produce  sexual  spores.  Where  only  asexual  spores  are   present,  the  fungus  is  known  as  Cercospera  arachidicola  and  Cercosporidium  personatum,   respectively.   Hosts:  Peanuts,  and  other  plants  belonging  to  the  genus  Arachis.    

Damage Infection  causes  early  death  of  the  leaves  and  yield  loss.  It  is  not  known  what  losses  these   diseases  cause  in  Solomon  Islands,  but  it  is  likely  that  they  reduce  yields  by  50%,  probably   much  more.  

Biology and  Life  Cycle   It  is  difficult  to  tell  the  two  leaf  spot  diseases  apart,  except  that  one  appears  later  than  the   other.  The  Early  leaf  spot  (photo,  left)  is  supposed  to  have  a  more  obvious  yellow  margin   around  the  brown  spot,  but  this  is  not  always  the  case.  The  Late  leaf  spot  (photo,  right)  is  black   rather  than  brown  on  the  underside  of  the  leaf,  but  this  is  not  always  obvious.  Examination  of   the  spores  under  a  microscope  is  needed  to  tell  the  fungi  apart.     The  first  sign  of  the  diseases  are  spots  on  the  older  leaves.  These  spread  rapidly  to  leaves  of  all   ages.  Spots  also  occur  on  the  petioles.  The  brown  or  red-­‐brown  leaf  spots  are  roughly  circular   up  to  10  mm  diameter  –  but  usually  smaller  -­‐  often  with  a  yellow  margin.  The  spots  are  darker   on  the  under  surface  of  the  leaf.     Masses  of  spores  are  produced  on  the  spots,  but  a  hand  lens  is  needed  to  see  them.  These  are   spread  by  wind  and  rain  splash.  The  spores  germinate  in  water  on  the  leaf  surface,  infect  and   produce  more  spots  and  spores.  The  life  cycle  takes  10-­‐14  days.  The  fungi  survive  in  crop   remains.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  inspection   Inspect  plants  regularly,  at  least  once  a  week,  looking  for  spots,  especially  on  the  older  leaves,   where  infections  first  occur.      

Management CULTURAL  CONTROL   Cultural  control  is  important.  The  following  should  be  done:   • Leave  at  least  1  year  between  crops  planted  on  the  same  land,  so  that  the  remains  of  the   old  crop  decomposes  before  another  crop  is  planted;   • Preferably,  remove  and  burn  or  bury  the  remains  of  the  crop  after  harvest;   • Plant  new  crops  as  far  away  as  possible  from  old  crops,  especially  those  with  leaf  spots;   • If  it  is  not  possible  to  avoid  planting  near  old  crops,  do  not  plant  down  wind  from  them;   otherwise,  spores  will  easily  spread  to  the  new  crop.    

RESISTANT VARIETIES   There  is  no  information  on  the  differences  between  varieties  grown  in  Solomon  Islands.  There   are  varieties  with  resistance  in  Papua  New  Guinea,  and  these  are  being  tested  in  Solomon   Islands.    

CHEMICAL CONTROL   • Carry  out  regular  inspections;   • Spray  as  soon  as  spots  are  seen,  even  if  they  appear  only  on  one  or  a  few  plants;   • Spray  regularly:  10-­‐14  days  is  best,  continuing  until  14  days  before  harvest.       Spray  more  often  if:   • The  first  treatment  is  late  and  there  are  many  plants  with  spots.  In  most  cases,  spraying   should  begin  no  later  than  30-­‐35  days  after  planting;   • Rainfall  is  high  and  control  is  poor.       Use  chlorothalonil  (the  trade  name  is  Bravo).  It  is  good  for  leaf  spots  and  also  rust  disease.   Copper  fungicides  can  also  be  used.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Bean Pod  Borer  

Extension Fact  Sheet  

37

Common  name:  Bean  pod  borer                                                                             Scientific  name:  Maruca  vitrata;  it  used  to  be  known  as  M.  testulalis.   Hosts:  Many  species  of  beans  are  hosts,  including  cowpeas,  pigeon  peas,  and  yardlong  beans.      

Damage The  caterpillars  do  the  damage.  They  bore  into  the  pods  and  eat  the  seeds.  There  is  also   damage  to  the  buds,  flowers  and  leaves  -­‐  they  may  be  eaten  and  bound  together  by  webs   made  by  the  caterpillars;  however,  damage  to  these  parts  is  not  large  in  comparison  to  that   done  to  the  pods.    

Biology and  Life  Cycle   Eggs  are  pale  cream,  translucent  (that  is,  they  allow  light  through),  and  laid  singly  on  the   stems,  young  leaves,  flowers  and  pods.  They  hatch  and  the  caterpillars  feed  inside  the  flowers   for  about  a  week;  then  they  move  to  the  pods.  They  are  pale  cream,  with  two  rows  of   markings  on  their  backs  (photo,  left1).  They  grow  to  18  mm  before  they  exist  the  pods  and   pupate  in  the  soil.  The  moths  (photo,  right)  have  brown  front  wings,  with  white  patches.  The   hind  wings  are  mostly  white  with  a  brown  border.    

Detection and  Inspection   Look  for  damaged  flowers,  and  leaves  and  pods  tied  together  by  webs  made  by  the   caterpillars.  Look  for  frass  -­‐  chewed  remains  of  the  pods  -­‐  around  entry  holes.  Look  for   caterpillars  inside  the  damaged  pods:  they  are  pale  with  two  rows  of  black  markings  on  their   backs.  The  moth  is  brown  with  a  white  patch  on  the  front  wings.       1 Image citations: Merle Shepard, Gerald R Carner, and PAC Ooi, Insects and their Natural Enemies Associated with Vegetables and Soybean in Southeast Asia, Bugwood.org (left); Gerald McCormack, Cook Islands Biodiversity Website: http://cookislands.bishopmuseum.org/ (right)

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management The  Bean  pod  borer  is  difficult  to  control,  especially  on  yardlong  beans.  Pesticides  are  not   recommended.  They  are:     • Likely  to  kill  natural  enemies;     • Not  very  effective  as  the  caterpillars  are  hidden  for  most  of  the  time  inside  the  pods;  and     • Expensive,  and  have  to  be  used  often.         There  are  lures  for  this  insect,  but  they  are  used  to  monitor  populations  before  insecticides  are   used.  Alternatively,  look  for  early  signs  of  webbing  of  the  flowers  by  the  caterpillars.    

CHEMICAL CONTROL   If  insecticides  are  necessary,  use  weekly  sprays  of  a  synthetic  pyrethroid  (for  example,  lambda   cyhalothrin)  to  kill  caterpillars  as  they  move  from  the  eggs  to  the  pods.  If  the  number  of  plants   is  small,  inspect  daily  and  hand  pick  the  eggs  and  young  caterpillars  on  the  flowers.       Avoid  the  use  of  broad-­‐spectrum  insecticides  to  avoid  killing  natural  enemies.     Preparations  using  neem  seed  extract  can  be  used  on  the  young  caterpillars  before  they  move   into  the  pods;  see  the  Kastom  Gaden  Association  for  seedlings.  

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Aphids

Extension Fact  Sheet  

38

Common  names:  There  are  many  aphids  attacking  a  wide  range  of  crops;  here,  we  describe   one  that  is  common  in  Solomon  Islands,  the  Melon  or  Cotton  aphid                                                                             Scientific  name:  Aphis  gossypii.   Hosts:  Aphids  occur  on  many  crops  and  weeds;  they  are  common  on  cucurbits  (cucumber,   melon,  watermelon)  and  taro.  They  are  also  found  on  chillies,  capsicum  and  eggplant.    

Damage Aphids  cause  direct  and  indirect  damage:   • Direct  damage:  Damage  due  to  feeding.  Aphids  have  fine,  needle-­‐like  mouthparts  and   they  use  them  to  suck  sap  from  plants.  When  they  are  numerous,  young  leaves  become   curled,  wrinkled,  cup-­‐shaped  and  smaller  than  normal.  Leaves  may  wilt,  dry  up  and  die   early.  When  populations  are  high,  plants,  especially  seedlings,  become  stunted;     • Indirect  damage:     o Sooty  moulds  grow  on  ‘honeydew’  -­‐  a  sweet,  sticky  liquid  produced  by  aphids  as   they  feed  -­‐  leaves  go  black  and  plant  growth  is  poor;     o They  spread  viruses  on  their  mouthparts,  such  as  the  viruses  of  cucurbits  -­‐   Cucumber  mosaic,  Papaya  ringspot  (watermelon  strain)  and  Zucchini  yellow   mosaic;  taro  -­‐  Dasheen  mosaic;  and  beans  -­‐  Bean  common  mosaic.  

Biology and  Life  Cycle   Males  are  rare  or  not  produced  in  tropical  countries.  Eggs  are  not  laid.  Females  give  birth  to   living  young  without  mating.  The  young  are  adult  in  4-­‐7  days,  after  moulting  four  times.  They   then  produce  4-­‐6  young  a  day,  up  to  50  each.  Because  of  this  method  of  reproduction,   populations  grow  rapidly,  with  many  generations  in  a  year.           AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  groups  of  round,  green  (some  may  be  light  green,  others  dark  green,  almost  black)   insects  on  the  underside  of  young  leaves,  on  shoots  and  buds  (photo,  left).  They  are  about  1   mm  long,  with  long  antennae  about  the  length  of  the  body,  and  two  tubes  at  the  rear  called   conicles.  Sometimes  winged  forms  occur,  up  to  2  mm  long  with  prominent  veins.  It  is  difficult   to  see  the  detail  of  the  body  with  the  naked  eye.  Look  for  ants,  they  are  often  present;  they   come  for  the  honeydew.  

Management NATURAL  ENEMIES   Aphid  predators  and  parasites  usually  keep  populations  low  (photo,  right).  The  most  common   are  lady  beetles  (adults  and  larvae),  syrphid  flies  (hover  flies)  larvae,  lacewing  larvae,  and  tiny   parasitic  wasps  that  lay  their  eggs  in  the  adult  aphids.  The  wasp  larvae  develop  in  the  aphids   eating  the  inside  parts  and  turning  the  aphids  into  empty  shells,  called  ‘mummies’.    

CULTURAL CONTROL   • • • • •

Remove weeds  from  within  and  also  outside  the  crop,  but  note  that  there  are  several   hundred  hosts  of  this  aphid  worldwide;     Burn  or  bury  the  remains  of  crops  after  harvest;   DO  NOT  plant  down-­‐wind  from  crops  with  aphids.  Some  aphids  have  wings,  but  they  are   not  strong  fliers  and  are  more  likely  to  be  blown  in  the  wind  onto  new  crops  ;   Inspect  crops  often  and  regularly;  destroy  leaves  heavily  infested  with  aphids;   Mulch  the  crop.  With  some  mulches,  aphids  find  it  more  difficult  to  distinguish  the  crop   plants  than  if  they  were  growing  in  bare  ground.  

CHEMICAL CONTROL   • •

• •

If ants  are  present,  kill  them  with  boiling  water,  without  damaging  the  crop  plants.   Without  the  ants,  predators  and  parasites  will  bring  about  natural  control;   If  insecticides  are  necessary,  use  any  of  the  following:   o Soap  sprays  (5  tablespoons  of  soap  in  4  litres  water);   o Vegetable  oil  (1  cup  cooking  oil;  2  cups  water;  1  teaspoon  dishwashing  liquid.  Dilute   the  mixture  at  3  teaspoons  per  half  a  litre  of  water  and  spray  on  the  infested  leaves);   o Commercial  products  with  petroleum  oil:  follow  the  instructions  with  the  product;     These  sprays  work  by  blocking  the  breathing  holes  of  insects  causing  suffocation  and   death.  Spray  underside  of  leaves:  the  oils  must  contact  the  aphids.   Use  synthetic  pyrethroids  (for  example,  lambda  cyhalothrin  or  cypermethrin).     A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.   Preparations  using  neem  seed  extract  can  be  used;  see  the  Kastom  Gaden  Association  for   seedlings.    

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sliperi Kabis  Leaf  hopper    

Extension Fact  Sheet  

39

Common names:  Sliperi  kabis  leafhopper  or  Sliperi  kabis  jassid                                                                           Scientific  name:  Amrasca.  The  species  reported  on  okra  worldwide  is  A.  biguttula  biguttula   (another  name  is  Amrasca  devastans),  and  this  may  be  the  same  as  that  attacking  sliperi  kabis   in  Solomon  Islands.  It  has  not  yet  been  identified.   Hosts:  In  Solomon  Islands,  the  jassid  has  been  found  only  on  sliperi  kabis  (Abelmoschus   manihot),  but  elsewhere  it  is  known  from  okra,  peanut,  soybean  and  other  legumes,  cotton,   eggplant  and  a  number  of  minor  hosts.    

Damage  

The jassids  (photo,  right)  cause  the  leaves  to  turn  yellow  in  patches  and  even  turn  white  at  the   edges  (photo,  left).  In  Solomon  Islands,  the  number  of  insects  per  leaf  is  small  in  relation  to  the   damage,  so  it  is  possible  that  the  jassids  inject  a  toxin  as  they  feed.  In  Papua  New  Guinea,  large   numbers  occur  on  the  leaves  and  cause  the  leaves  to  dry  up,  beginning  at  the  leaf  margins,  and   die  prematurely,  especially  during  times  of  low  rainfall.  The  damage  reduces  the  number  of   leaves  available  for  consumption,  and  may  also  reduce  their  nutritional  content,  although  this   has  not  been  tested.    

Biology and  Life  Cycle   Eggs  are  laid  in  the  leaves  and  the  leaf  stalks.  The  egg  hatch  in  8-­‐10  days,  and  the  yellow-­‐green   nymphs  look  similar  to  the  adults  except  in  size,  and  the  fact  that  they  are  wingless.  They   moult  four  times  before  they  are  mature;  they  are  then  about  2  mm  long.  Both  nymphs  and   adults  are  wedge-­‐shaped.  It  is  likely  that  the  life  cycle  is  complete  within  2  weeks.     Jassid  populations  are  influenced  by  rainfall.  High  rainfall  causes  many  deaths  of  nymphs  and   adults.    

Detection and  Inspection   Look  at  the  leaves  and  see  if  they  have  light  yellow  to  white  patches.  Look  at  the  underside  of   the  leaf  and  find  the  jassids.  There  may  not  be  many  present  on  each  leaf.  The  leaves  may  be    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   more  crinkled  than  normal,  but  remember  that  leaves  of  some  varieties  of  sliperi  kabis  are   crinkled  even  when  healthy.  It  is  easier  to  see  the  jassids  if  dark  paper  is  put  beneath  the   leaves,  and  they  are  then  shaken  or  given  a  sharp  tap.  

Management NATURAL  ENEMIES   A  number  of  natural  enemies  of  jassids  have  been  reported  worldwide.  The  larvae  of  lady   beetles  and  lacewings,  spiders  and  other  predators  attack  both  adults  and  nymphs.  Tiny  wasps   are  also  reported  that  attack  the  eggs  of  jasssids.  Bacteria,  Bacillus  thuringiensis  kurstaki,  have   been  recorded  infecting  nymphs  and  adults.  Whether  or  not  these  or  other  natural  enemies   are  present  in  Solomon  Islands,  and  attack  jassids  in  the  same  way,  is  not  known.    

RESISTANT VARIETIES   One  variety  appears  to  have  resistance  (photo,  right).  This   is  a  variety  from  the  Western  Province.  It  may  be  an   introduction  from  Papua  New  Guinea.  The  leaves  are   deeply  dissected  into  long  narrow  leaflets,  with  a  waxy   green  surface  and  dark  leaf  stalks;  the  plant  is  tall  and   narrow.  See  Kastom  Gaden  Association  for  details  and   planting  material.    

CHEMICAL CONTROL   Use  insecticides  that  have  fast  action  and  low  residual   effect,  that  is,  they  break  down  quickly.  The  aim  is  to  do   the  least  harm  to  the  natural  enemies.  Note  the  following:     • In  Papua  New  Guinea,  Derris  (Derris  ellipica)  is   recommended.  Derris  contains  rotenone,  an  insecticide.  Derris  is  planted  within  or  around   sliperi  kabis  plots,  ready  for  use  when  required.  The  roots  are  used  to  make  a  spray.   Solomon  Islands  has  a  variety  from  PNG  that  also  has  a  high  rotenone  content.  See  MAL   and  KGA  for  a  supply  of  plants  and  the  way  to  make  the  spray.   • Alternatively,  use  synthetic  pyrethroid,  such  as  lambda  cyhalothrin  or  permethrin,  which   are  available  in  Honiara.     • For  experimental  use,  try  those  products  that  contain  disease-­‐causing  organisms,  such  as   spinosad  (Success)  and  Bt  –  Bacillus  thuringiensis  kurstaki.  Spinosad  and  Bt  are  sometimes   sold  in  Honiara.  Note,  under  Natural  enemies  above,  Bt  has  been  found  to  kill  nymphs  and   adults.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Pumpkin Beetle  

Extension Fact  Sheet  

40

Common  name:  Plain  or  Red  pumpkin  beetle                                                                           Scientific  name:  Aulacophora  indica.     Hosts:  Cucurbits  are  hots;  common  cucurbits  are  cucumber,  melon,  pumpkin,  watermelon  and   gourds.  Similar  species  are  pests  of  these  plants  in  India,  the  Philippines,  Japan  and  Australia.        

Damage Adults  (photo,  right)  feed  on  leaves,  chewing  large  holes  (photo,  left).  Seedlings  are   particularly  susceptible,  and  so  are  young  plants  after  planting  out.  The  damage  to  young   plants  can  delay  crop  maturity.  Damage  also  occurs  on  flowers  and  small  fruit.       The  larvae  damage  roots,  stems  and  fruits,  but  evidence  of  this  has  not  been  looked  for  in   Solomon  Islands.  Such  damage  allows  entry  of  other  organisms,  for  example,  fungi.    

Biology and  Life  Cycle   The  life  cycle  has  been  studied  under  the  old  name  Aulacophora  similis.  Females  lay  yellow,   oval  eggs  singly  or  in  batches  in  soil  around  the  base  of  the  host.  After  5-­‐15  days,  they  hatch,   and  the  cream-­‐white  young  (called  larvae)  burrow  into  the  soil  to  feed  primarily  on  the  roots.   Four  moults  occur  over  14-­‐25  days,  and  then  the  larvae  enter  the  pupal  stage  in  an  earth   chamber;  this  lasts  another  7-­‐20  days  before  the  adults  emerge.     Females  lay  up  to  500  eggs,  and  live  as  long  as  10  months.  This  means  there  are  several   overlapping  generations  each  year.      

Detection and  Inspection   Look  for  red  oval  beetles,  about  8  mm  long,  on  the  leaves  and  flying  between  them.  They  are   often  in  groups  on  both  young  and  old  leaves.  Look  for  the  circles  eaten  by  the  beetles,  and   the  large  holes  in  the  leaves  between  the  veins.  Often,  the  groups  of  beetles  will  attack  the  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   same  leaf,  leaving  only  the  veins,  before  moving  to  other  leaves.  Adults  are  strong  fliers,  and   quickly  take  to  the  wing  when  disturbed.     A  similar  coloured  leaf  beetle,  Monolepta,  has  a  dark  area  on  the  triangular  piece  at  the  base   of  the  wing  cases.  It  also  has  a  smooth  thorax  -­‐  the  part  behind  the  head.  By  contrast,   Aulacophora  has  a  groove  across  the  thorax  (this  can  be  seen  in  photo,  right).  (See  Fact  Sheet   no.  53  for  Monolepta.)  

Management There  is  little  known  about  the  natural  control  of  these  beetles.  The  beetles  contain  chemicals   that  visual  predators  do  not  like,  and  are  avoided  by  them.  The  bright  colours  of  this  beetle   warn  predators  that  they  are  distasteful.    

RESISTANT VARIETIES   •  

Fast growing  varieties  are  more  likely  to  outgrow  the  damage  caused  by  the  beetles.  

CULTURAL CONTROL   • • • •

Avoid planting  new  crops  next  to  those  already  infested  with  the  beetles;   Provide  conditions  for  healthy  plant  growth,  especially  for  seedlings;  that  may  include   manures  and/or  commercial  fertilizers,  and  adequate  water;   The  beetles  tend  to  group  together  feeding  on  some  plants,  leaving  others;  plant  extra   seed  to  compensate  for  this;   In  the  early  morning  or  evening,  it  is  possible  to  catch  the  beetles  in  flight;  this  is  a  useful   control  method  in  small  gardens.  Perhaps  a  game  for  children!  

CHEMICAL CONTROL   •

Use synthetic  pyrethroid  insecticides,  such  as  lambda  cyhalothrin  or  permethrin.  The   choice  of  chemical  is  important:  use  those  that  are  least  persistent  in  the  environment,   and  have  low  toxicity  against  bees;   Try  wood  ash:  Add  ½  cup  of  wood  ash  and  ½  cup  of  lime  in  4  litres  water;  leave  to  stand  for   some  hours;  strain;  test  on  few  infested  plants  first  to  make  adjustment  of  the  strength   before  going  into  large-­‐scale  spraying.  

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Taro Plant  Hopper  

Extension Fact  Sheet  

41

Common  name:  Taro  planthopper                                                                           Scientific  name:  Tarophagus  spp.  There  are  three  species  present  in  the  Pacific:  T.  colocasiae;   T.  persephone;  and  T.  proserpina.  All  are  present  in  Papua  New  Guinea,  but  whether  they  are   all  present  in  Solomon  Islands  is  not  known.   Hosts:  Taro,  but  it  has  been  recorded  occasionally  on  Alocasia  (edu)  and  Cyrtosperma  (kakake).    

Damage Damage  is  done  in  two  ways:   • Direct  damage:  The  planthoppers  have  needle-­‐like  mouthparts,  which  are  used  to  suck  sap   from  taro  leaves.  When  numbers  are  high  and,  especially  in  dry  weather,  the  leaves  wilt   and  new  leaves  are  stunted.  Typically,  the  leaf  stalks  bend  down  so  that  plants  are  wider   than  normal,  and  corms  are  smaller.     • Indirect  damage:  Planthoppers  spread  the  viruses  associated  with  Alomae  and  Bobone:   Colocasia  bobone  disease  rhabdovirus  and  Taro  vein  chlorosis  rhabdovirus.    

Biology and  Life  Cycle   Eggs  are  laid  in  the  midrib  of  the  leaves  and  in  the  petioles,  often  at  the  base.  A  slot  is  cut  and   10-­‐20  eggs  are  placed  inside.  The  eggs  hatch  after  about  15  days.  At  first,  the  young  or  nymphs   are  white;  later,  as  they  moult  -­‐  four  times  over  about  20  days  -­‐  they  become  brown  and  then   black  with  white  markings.  For  most  of  the  time,  the  adults  develop  without  wings  (photo,   above  right).  Winged  forms  appear  when  the  crop  matures  and/or  when  the  population  is  high   (photo,  lower  right).  They  are  about  4  mm  long;  the  wingless  ones  are  shorter.     Heavy  rains  reduce  populations  of  planthoppers.  The  youngest  nymphs  are  particularly   susceptible  to  drowning  in  the  water  that  collects  between  the  petiole  bases.      

Detection and  Inspection   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Planthoppers  group  together  where  humidity  is  greatest:  on  the  underside  of  leaves;  inside   leaves  that  are  beginning  to  unfurl;  and  especially  between  the  petioles  at  the  base  of  the   plant.  The  planthoppers  have  a  characteristic  way  of  moving  sideways  across  the  leaf  or   petiole.  Also,  nymphs  and  adults  jump  if  disturbed.       Look  for  dirty  marks  on  the  petioles,  especially  on  the  lower  parts;  the  plant  sap  oozes  out  as   the  planthoppers  feed  and  lay  eggs,  and  it  hardens  to  form  a  red-­‐brown  crust.    

Management NATURAL  ENEMIES   An  egg  predator,  Cyrtorhinus  fulvus,  reduces  the  numbers  of  the  planthopper,  except  in  dry   times  when  populations  of  both  insects  can  be  high.  Often,  ants  tend  the  planthoppers,   presumably  attracted  to  the  honeydew  produced  as  they  suck  the  sap  from  the  leaves.  Three   species  of  parasites  have  been  reported  parasitising  eggs  and  nymphs;  and  spiders  and   ladybeetle  larvae  also  feed  on  them.  

CULTURAL CONTROL   • •

Avoid planting  new  crops  next  to  those  already  infested  with  planthoppers,  otherwise  the   winged  forms  will  easily  find  the  new  crop;   Prepare  ‘tops’  for  replanting  by  cutting  off  all  leaves  with  dirty  marks  on  them  to  avoid   taking  planting  material  with  eggs  to  new  gardens.  Use  of  ‘clean’  planting  material  in  this   way  is  an  important  method  of  control.  

CHEMICAL CONTROL   • • •

Chemical control  is  rarely  needed,  except  during  extended  dry  periods,  when  populations   can  build  up  to  damaging  levels;   If  egg-­‐eating  bugs  are  not  present,  or  are  not  effective,  use:  a)  synthetic  pyrethroids,  such   as  lambda  cyhalothrin  (Karatee)  or  cypermethrin  (Mustang);  or  b)  imidacloprid  (Confidor);   A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  may  be  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.  

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Maize Rust  

Extension Fact  Sheet  

42

Common  name:  Maize  rust   Scientific  names:  Puccinia  polysora  is  recorded  from  Solomon  Islands,  but  there  is  another   rust,  P.  sorghi,  that  has  not  been  recorded.  P.  sorghi  is  found  in  Australia  and  elsewhere.  Often   the  two  rusts  occur  together,  requiring  microscopic  examination  to  tell  them  apart.     Hosts:  Maize  and  sweet  corn.  It  is  recorded  on  some  grasses  and  relatives  of  maize  in  other   countries;  it  has  only  been  recorded  from  maize  in  Solomon  Islands.    

Damage The  disease  is  usually  of  minor  importance.  Most  spots  occur  on  the  older  leaves;  these  dry   and  die  earlier  than  those  that  remain  uninfected,  but  the  rust  comes  late  in  the  growth  of  the   plant,  after  the  seeds  have  been  filled.  Maize  varieties  have  been  selected  for  resistance  to  this   rust.      

Biology and  Life  Cycle     The  spots,  produced  in  large  numbers  on  both  sides  of  the  leaf  (photo,  left),  and  also  on  the   stem  (photo,  right),  are  round  to  oval,  up  to  2  mm;  they  are  brown,  releasing  large  numbers  of   powdery  spores.  They  burst  open,  and  the  spores  are  spread  by  wind  over  long  distances.  The   spores  germinate  in  water  on  the  surface  of  the  plants  and  infect  through  natural  openings   (stomata).  Warm,  humid  weather,  such  as  occurs  in  Solomon  Islands,  favours  the  development   of  the  disease.       The  disease  is  called  ‘rust’  because  of  the  powdery  spores.  If  you  wipe  a  finger  over  the  leaf,  it   appears  similar  to  touching  rusty  iron  –  a  fine  dark  brown  stain  remains.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection    

The rust  usually  appears  late,  after  the  appearance  of  the  male  flower  or  tassel.  If  the  leaf  is   held  against  the  light,  the  spots  can  be  clearly  seen.  There  is  a  dark  centre  surrounded  by  a   yellow  margin.    

Management  

CULTURAL CONTROL   Cultural  control  is  important.  The  following  should  be  done:   • Destroy  volunteer  plants  as  the  rust  can  only  survive  on  living  plants;   • Plant  maize  during  the  drier  times  of  the  year;   • The  rust  can  be  seed  borne,  but  the  spores  survive  for  only  2  months,  so  infection  from   seeds  is  not  usually  a  risk.    

RESISTANT VARIETIES   There  are  resistant  hybrids  of  maize  and  sweet  corn.    

CHEMICAL CONTROL   The  use  of  fungicides  against  this  disease  is  not  recommended  as  the  effect  on  yield  is   probably  minor  and  their  use  would  not  be  economic.  If  needed,  copper  and  mancozeb  would   be  effective.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Bean  Virus  

Extension Fact  Sheet  

43

Common  name:  Bean  common  mosaic  virus.  In  a  survey  for  viruses  of  Solomon  Islands  in  1987   by  Alan  Brunt,  this  virus  is  referred  to  as  Blackeye  cowpea  mosaic  virus.   Scientific  names:  Bean  common  mosaic  potyvirus.  Particles  are  shaped  like  flexuous  rods.   Hosts:  The  virus  has  been  recorded  in  the  following  legumes  in  Solomon  Islands:   Calopogonium  mucunoides,  Centrosema  pubescens,  Clitorea  ternatea,  Desmodium   heterophylum,  Macroptilium  atropurpureum,  M  lathyroides,  Phaseolus  vulgaris  (French  beans),   Pueraria  phaseoloides,  Stylosanthes  guianensis,  Vigna  marina,  Vigna  unguiculata  ssp.   sesquipedalis.  The  last  is  called  snake  bean  in  Solomon  Islands.  It  is  also  called  long  bean  or   yard  long  bean.  Cowpea  and  soybean  are  also  hosts.   In  a  2007  survey,  the  virus  was  recorded  in  wild  passion  fruit,  Passiflora  foetida.    

Damage The  virus  is  important  on  long  bean,  especially  when  infection  comes  from  planting  diseased   seed.  In  this  case,  symptoms  appear  early:  plants  are  dwarfed,  pods  are  shorter  and  fewer   than  normal  and,  consequently,  yields  are  low.  

Biology and  Life  Cycle   Seed  infection  can  be  high,  over  30%.  Spread  from  these  plants  is  by  aphids,  and  it  can  occur   very  quickly.  The  virus  can  remain  alive  in  bean  seeds  for  many  years.  The  virus  is  also  spread   in  pollen.  However,  seed  transmission  is  the  most  important  method  of  spread.       If  the  first  leaves  to  develop  show  light  and  dark  green  patches,  and  the  leaves  are  misshapen   (photo,  right),  then  it  is  likely  that  the  seed  was  infected  by  Bean  common  mosaic  virus.    

Detection and  inspection   Look  for  patches  of  light  and  dark  green  on  the  leaves  (this  symptom  is  called  a  mosaic,  i.e.,   photo,  left),  and  for  leaves  that  are  misshapen.  The  leaves  may  be  puckered,  i.e.,  there  are   bumps  on  the  surface  of  the  leaves  (photo,  right).     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management CULTURAL  CONTROL   Cultural  control  is  important.  The  following  should  be  done:   • Interplant  beans  with  other  plants,  e.g.,  maize;   • Plant  mixture  of  long  bean  varieties  –  a  strategy  used  in  parts  of  Africa.  Contact  MAL   and/or  Kastom  Gaden  Association  for  sources  of  seed;   • Do  not  plant  new  crops  next  to  those  that  have  the  disease;   • The  virus  is  seed  borne,  so:     o Carefully  select  plants  for  seed  that  do  not  show  symptoms  of  the  disease;     o If  most  plants  show  symptoms,  search  for  a  new  source  of  seed  (or  contact  MAL  or   KGA),  and  discard  the  seed  that  is  severely  infected.    

RESISTANT VARIETIES   Currently,  trials  are  being  done  in  Solomon  Islands  with  varieties  of  long  beans  from  AVRDC   (now  known  as  The  World  Vegetable  Centre).  Contact  MAL  and/or  KGA  for  a  source  of  seed  to   test.  

CHEMICAL CONTROL   The  use  of  insecticides  for  the  control  of  aphids  that  spread  the  virus  is  not  recommended.  The   time  between  an  aphid  sucking  up  the  virus  when  it  feeds  on  a  diseased  plant,  and  spreading   the  virus  as  it  feeds  again  on  a  healthy  plant,  is  short.  By  the  time  the  insecticide  has  killed  the   aphid  it  has  spread  the  virus.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Kongkong Taro  Root  Rot  

Extension Fact  Sheet  

44

Common  name:  Kongkong  taro  root  rot   Scientific  names:  Pythium  species.  Pythium  species  are  soil  borne  pathogens  that  attack  the   roots  and  underground  parts  of  many  plants.   Hosts:  Colocasia  taro,  edu  (Giant  taro,  Alocasia)  and  kongkong  taro  (Xanthosoma)  are   susceptible.  Other  plants  infected  in  the  field  are  beans,  capsicum  and  ginger;  many  other   plants  are  infected  as  seedlings  in  the  nursery.  Pythium  causes  a  damping-­‐off  disease  (see  Fact   Sheet  No.  47).  Note,  Pythium  is  not  a  fungus,  it  belongs  to  the  groups  known  as  Water  moulds   or  oomycetes,  related  to  algae.    

Damage Root  rot  is  the  most  important  disease  of  kongkong  taro  worldwide.  It  is  particularly  important   in  West  Africa  and  in  Central  America.  It  has  been  recorded  in  several  Pacific  countries.  It  is   rare  in  Solomon  Islands,  possibly  because  gardens  contain  only  a  few  plants  at  any  one  time.    

Biology and  Life  Cycle   The  first  sign  of  the  disease  in  mature  plants  is  the  drying  up  of  the  outer  older  leaves  (photo,   left).  As  the  disease  progresses,  the  number  of  leaves  declines,  young  leaves  are  shorter  and   smaller  than  usual,  and  eventually  the  plant  can  be  pulled  easily  from  the  soil.  Roots  are   absent  on  these  plants  or  only  present  at  the  very  top  of  the  corm  (photo,  right).  In  young   plants,  growth  is  slow,  and  plants  remain  with  one  or  two  leaves  for  months,  as  the  roots  are   destroyed  as  soon  as  they  are  produced.  Corm  rots  may  be  present,  but  this  is  a  late  symptom.     Pythium  has  a  wide  host  range  and  can  infect  many  crops  and  weeds.  When  conditions  are  not   favourable  or  when  susceptible  hosts  are  not  present,  Pythium  produces  resistant  spores  -­‐   oospores  -­‐  that  remain  alive  but  inactive  in  the  soil  for  many  years.  They  germinate  when   conditions  are  right  and  produce  swimming  spores  in  large  number  that  infect  the  roots  of   susceptible  plants.  The  disease  is  especially  severe  on  plants  grown  in  soils  that  waterlog.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Carefully  dig  up  the  plants,  do  not  pull  them  from  the  ground.  Look  to  see  if  roots  are  decayed,   especially  the  small  feeder  roots;  these  are  the  roots  that  take  water  and  minerals  from  the   soil  and  supply  the  leaves.  Without  these  roots,  the  leaves  wilt  and  die.  

Management CULTURAL  CONTROL   Cultural  control  is  important.  The  following  should  be  done:   • Choose  sites  carefully.  DO  NOT  plant  where  the  land  is  likely  to  flood,  or  where  water  will   remain  for  several  days  after  heavy  rains;   • Preferably,  avoid  heavy  clay  soils;  where  this  is  not  possible,  make  drains  around  the  plots   or  plant  the  taro  on  raised  beds  or  mounds  to  provide  drainage;   • If  planting  material  is  taken  from  plants  that  have  shown  root  rot  symptoms,  carefully   remove  all  the  roots,  old  leaves  and  soil,  before  planting  in  a  new  garden;   • Do  not  plant  kongkong  taro  in  land  below  where  root  rot  occurred  previously.  If  you  do,   spores  of  the  Water  mould  will  spread  in  soil  or  surface  water  during  rains.    

RESISTANT VARIETIES   There  is  no  information  about  resistant  varieties  of  kongkong  taro.  Colocasia  taro  varieties   with  resistance  are  known  from  Samoa,  but  these  varieties  (one  of  them  is  Tusi  tusi)  are   susceptible  to  Taro  leaf  blight.    

CHEMICAL CONTROL   Fungicides  are  not  recommended  for  the  control  of  this  disease;  they  are  unlikely  to  be   economic.  When  the  symptoms  appear,  damage  to  the  roots  has  already  been  done.  It  is  best   to  carry  out  the  cultural  control  recommendations  stated  above.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Black Leaf  Mould  

Extension Fact  Sheet  

45

Common names:  Leaf  spot,  Black  leaf  mould,  Tomato  leaf  mould   Scientific  name:  Pseudocercospora  fuligena.  Previously  known  as  Cercospora  fuligena.   Host:  Tomato.  It  is  also  said  to  infect  bell  pepper  and  chilli,  but  it  has  not  been  found  on  those   plants  in  Solomon  Islands.    

Damage The  fungus  causes  plants  to  lose  their  leaves.  If  infection  occurs  before  the  fruit  has   developed,  yields  are  low.  This  is  the  most  important  disease  on  tomato  in  Solomon  Islands.  

Biology and  Life  Cycle   The  disease  starts  on  the  older  leaves  and  spreads  upwards.  The  first  signs  are  irregular   yellow  patches,  mostly  at  the  edge  of  the  leaves  (photo,  left).  The  patches  turn  brown  rapidly,   and  the  leaves  dry,  curl,  hang  down  and  later  fall  off.  On  the  underside  of  the  dry,  brown   leaves  spores  form  in  the  patches,  which  appear  like  a  brown  or  dark  brown  mould.  There  are   no  symptoms  on  the  fruit.     The  spores  are  spread  by  wind  blown  rain,  and  if  windy  wet  weather  continues  for  a  few  days,   spread  is  fast  and  plants  defoliate  quickly.       The  source  of  the  fungus  is  from  other  infected  crops,  the  remains  of  the  previous  crop  and,   perhaps,  other  host  species.  The  fungus  is  not  seed  borne.  

Detection and  inspection   Look  for  the  disease  on  the  bottom  leaves.  Look  for  the  brown  patches,  especially  at  the  leaf   margins,  and  the  mould-­‐like  spore  masses  on  the  older  dead  leaves.  

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management CULTURAL  CONTROL   Cultural  control  is  important.  The  following  should  be  done:     • Remove  and  burn  the  lower  leaves  as  soon  as  the  disease  is  seen,  especially  after  the   lower  fruit  trusses  have  been  picked;   • Collect  and  burn  as  much  of  the  crop  as  possible  when  harvest  is  complete;   • DO  NOT  plant  new  crops  next  to  older  ones  that  have  the  disease.     RESISTANT  VARIETIES   Currently,  trials  are  being  done  in  Solomon  Islands  with  varieties  of  tomatoes  from  AVRDC   (now  known  as  The  World  Vegetable  Centre).  Contact  MAL  for  a  source  of  seed.  Some   varieties  show  resistance  to  the  disease  (photo,  right)     CHEMICAL  CONTROL   The  warm  wet  conditions  in  Solomon  Islands  favours  the  disease  such  that  fungicides  are   needed  to  give  adequate  control.  The  products  to  use  are  chlorothalonil  (Bravo),  copper   oxychloride  or  mancozeb.  Treatment  should  start  when  the  first  flowers  appear,  and  continue   at  10-­‐14  days  intervals  until  3-­‐4  weeks  before  last  harvest.  It  is  important  to  spray  both  sides   of  the  leaves.     Azole  fungicides  (e.g.,  difenoconazole)  are  also  recommended  for  control  of  this  disease.  But   these  are  rarely,  if  ever,  sold  in  Solomon  Islands.     Note,  there  is  another  disease  that  has  similar  symptoms.  It  is  called  Tomato  leaf  mould,  and   is  caused  by  the  fungus,  Passalora  fulva.  This  fungus  and  Pseudocercospora  fuligena  can  only   be  distinguished  by  looking  at  their  spores  under  a  microscope.  (See  Fact  Sheet  no.  76  for   Passalora.)    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Boil Smut    

Extension Fact  Sheet  

46

Common  names:  Boil  smut,  Common  smut1   Scientific  name:  Ustilago  zeae;  previously  known  as  U.  maydis.     Host:  Maize,  sweet  corn.  

Damage The  disease  has  been  present  in  Solomon  Islands  for  nearly  30  years,  but  the  number  of   plants  infected  in  any  crop  remains  low.  Presumably,  this  is  because  conditions  do  not   favour  the  disease,  the  crop  is  not  grown  in  the  same  land  one  year  after  another,  or  the   varieties  grown  have  some  resistance  to  infection.  Where  infection  does  occur,  however,  the   maize  fruit  -­‐  the  ear  -­‐  becomes  distorted  and  the  individual  seeds  swell  becoming  galls  filled   with  enlarged  plant  cells,  fungal  threads  and  a  mass  of  spores  (photo).  Thus,  there  is   reduction  in  yield.  Other  parts  of  the  plant  -­‐  leaves  and  stems  -­‐  are  also  susceptible  to   infection,  but  less  so.     Early  infection  results  in  stunted  plants  and  even  death,  although  this  is  uncommon.  Overall,   boil  smut  is  a  minor  disease  of  maize  and  sweet  corn  in  Solomon  Islands.     Note,  in  Mexico,  maize  smut,  known  as  huitlacoche,  is  eaten.  The  galls  are  harvested  while   still  young,  and  when  cooked  have  a  mushroom-­‐like  flavour.   1 Much of the information in this Fact Sheet is taken from Boil smut of corn. NSW, DPI primefacts. Primefact 247. September 2006.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Biology and  Life  Cycle   The  fungus  infects  all  the  aboveground  parts,  especially  young  growing  tissues.  Systemic   infection,  i.e.,  the  fungus  infects  and  grows  through  the  plant,  occurs  in  seedlings,  but  not  in   older  plants.  Infection  is  increased  by  injury  to  the  plants,  such  as  occurs  during  cultivation.     Boil  smut  is  a  soil  borne  disease.  The  spores  remain  alive  in  the  soil  for  many  years.  They   germinate  and  produce  a  second  type  of  spore;  these  are  the  spores  that  infect  the  plants.   They  are  carried  on  the  wind  or  splashed  by  water  to  young  maize  plants.  The  spores   germinate,  infect,  and  cause  the  plants’  cells  to  grow  and  multiply  and  form  the  galls.     Galls  form  on  leaves,  stalks,  ear  and  tassels.  They  grow  to  15  cm  on  the  ears,  but  those  on   the  leaves  remain  smaller,  6-­‐12  mm,  become  hard  and  dry,  and  produce  few  spores.  The   galls  on  the  ears  are  at  first  enclosed  in  a  white  to  light  grey  covering,  before  splitting  to   release  dark  brown  to  black  spores.  One  gall  may  produce  200  billion  spores!     Smut  spores  contaminate  maize  seeds,  and  this  is  the  way  that  the  fungus  is  introduced  into   new  areas.  The  spores  can  also  be  spread  on  machinery,  people,  livestock  and  fodder.  

Detection and  inspection   Look  for  smut  galls  on  leaves,  stalks,  ears  or  tassels.  Galls  are  firm  initially,  white  or  grey,   later  bursting  to  release  the  black  powdery  spores.  Severely  infected  plants  may  be  stunted.  

Management CULTURAL  CONTROL   Cultural  control  is  important.  The  following  should  be  done:   • Remove  infected  plants  before  the  galls  rupture,  and  burn  the  plants;   • DO  NOT  replant  maize  in  land  where  the  disease  was  present  previously;   • Avoid  over-­‐fertilizing  with  nitrogen,  as  this  increases  susceptibility;   • Be  careful  not  to  injure  the  plants  during  cultural  operations.    

RESISTANT VARIETIES   There  appears  to  be  good  field  resistance  to  boil  smut  in  the  varieties  grown  in  Solomon   Islands,  as  the  percentage  infection  is  low.  Sweet  corn  varieties  are  more  susceptible,  but   the  disease  is  not  common  in  them  either.    

CHEMICAL CONTROL   In  Australia,  seed  is  treated  with  the  fungicide,  carboxin  (Vitavax)  and  thiram.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Seedling Damping-­‐Off  

Extension Fact  Sheet  

47

Common  name:  Damping  off   Scientific  names:  Commonly,  Pythium  and  Rhizoctonia  are  involved,  but  Fusarium  and   Phytophthora  may  also  cause  similar  diseases.  Note,  Pythium  and  Phytophthora  are  NOT   fungi  but  Water  moulds,  related  to  algae.   Host:  Many  kinds  of  fruit  and  vegetable  seedlings  show  the  disease  in  the  nursery,  with   tomatoes,  cabbages,  and  lettuces  especially  susceptible.  The  photo,  left,  shows  damping  off   in  taro1.    

Damage Seedlings  are  attacked  by  damping-­‐off  fungi  and  Water  moulds  (Pythium  is  not  a  fungus)   either  before  they  emerge  (called  pre-­‐emergence  damping  off)  or  after  (called  post-­‐ emergence  damping  off).  Pre-­‐damping  off  results  in  gaps  in  the  rows  of  seedlings,  whereas   the  post-­‐damping  off  results  in  seedlings  that  fall  over  due  to  root  rots  and  stem  infections,   often  at  soil  level  (photo,  right).  Those  that  survive  the  attack  may  be  stunted,  or  grow   slowly.     Seedlings  that  have  strong  stems,  such  as  cabbages,  do  not  always  fall  over;  the  plants  have   thin,  twisted,  discoloured  stems  (known  as  wire  stem).  If  the  infection  girdles  the  stem,  the   seedlings  die  eventually.  

Biology and  Life  Cycle   The  fungi  and  Water  moulds  involved  in  damping  off  are  widely  distributed  in  soil.  They  live   on  organic  matter,  but  also  on  the  roots  of  living  plants  as  parasites.  Most  prefer  wet  soil   conditions,  and  some  have  spores  that  swim  in  soil  water,  e.g.,  Pythium  and  Phytophthora.   Rhizoctonia  and  Fuarium,  by  contrast,  do  not  like  waterlogged  soils.      

1

The photo was taken by Tolo Iosefa, University of the South Pacific, Samoa.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Plants  that  are  growing  poorly,  because  the  soil  is  waterlogged  or  the  temperature  is   unsuitable,  are  more  likely  to  be  infected  by  damping-­‐off  fungi  and  Water  moulds,  in   contrast  to  those  seedlings  growing  rapidly.       Spread  of  these  fungi  and  Water  moulds  occurs  in  water  splash,  on  contaminated  tools,  in   potting  mixes  and  in  infected  plants.    

Detection and  inspection   Look  for  gaps  in  the  row,  and  if  present  look  to  see  if  the  seed  is  decayed.  Look  for  seedlings   that  have  fallen  over  due  to  soft  rots  on  the  stem  or  decayed  roots.  Look  for  lesions  and   cankers  (open  lesions)  on  seedlings  with  strong  stems.  Threads  of  the  fungi  involved  may  be   present  over  the  soil  and  seedlings  (photo,  left).  

Management CULTURAL  CONTROL   Cultural  control  is  important.  The  following  should  be  done:   • Sterilise  the  soil  mix:     o Heat  the  soil  in  an  earth  oven  over  hot  stones  covered  in  leaves  or  sacks  for  at   least  one  hour,  or     o Place  the  soil  mix  in  boxes  or  place  it  on  the  ground  between  bamboo  sections,   and  pour  boiling  water  over  the  soil;   • Keep  the  treated  soil  in  clean  bags  until  it  is  used,  to  prevent  reinfection  from  water   splash  or  contaminated  tools;   • If  outbreaks  of  damping  off  occur  in  seed  beds,  move  the  beds  to  a  different  site;     • Water  soil  and  plants  with  rain  water,  not  with  water  from  ponds,  streams,  etc.;   • DO  NOT  overwater  seedlings;  ensure  the  seed  boxes  have  good  drainage;   • Raise  nursery  seed  boxes  above  ground  level  (at  least  1  metre)  to  avoid  rain  splash  from   the  soil;   • Always  use  a  nutritious  soil  mix:  rotten  coconut  mixed  with  soil  is  best.  If  using  home   made  compost  make  sure  it  is  well  rotted  before  mixing  it  with  the  grated  coconut.  (See   leaflet,  Growing  lettuces,  Chinese  and  English  (ball)  cabbage  the  organic  way  by  Joini   Tutua).    

RESISTANT VARIETIES   It  is  unlikely  that  in  any  one  kind  of  vegetable  there  will  be  differences  in  the  susceptibility  of   varieties  to  damping  off.      

CHEMICAL CONTROL   If  cultural  control  methods  fail,  treat  seed  with  a  fungicide,  such  as  thiram.  Fungicides  can   also  be  used  to  treat  seedbeds  and/or  seed  boxes.  See  MAL  for  advice.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Citrus Scab  

Extension Fact  Sheet  

48

Common  name:  Common  citrus  scab   Scientific  names:  Elsinoë  fawcettii.  The  fungus  has  an  asexual  stage,  Sphaceloma  fawcettii;  this   is  the  stage  that  occurs  in  Solomon  Islands  and  elsewhere  in  the  Pacific.  There  are  other  strains   of  S.  fawcettii  present  in  other  countries.     Hosts:  Lemon,  rough  lemon  and  mandarin.  Other  species  of  citrus  –  grapefruit,  orange  and   pomelo  -­‐  are  also  susceptible,  but  less  so.    

Damage.   The  fungus  distorts  the  leaves,  and  causes  unsightly  infections  on  the  fruit.  Infections  may   reduce  market  value  of  the  fruits,  but  it  is  unlikely  to  affect  yield.  The  disease  is  more  serious   on  seedlings  in  the  nursery,  especially  on  susceptible  roots  stocks:  sour  oranges,  rough  lemons,   Rangpur  lime,  Poncirus  trifoliata  and  Citrus  limonia.  It  may  stunt  the  seedlings,  making  them   difficult  to  bud.     Overall,  scab  is  a  minor  disease  in  mature  plantations,  causing  little  economic  damage.  It  is   more  serious  as  a  disease  of  nurseries.  

Biology and  Life  Cycle   Wart-­‐like,  raised  light-­‐brown  pustules  or  scabs  are  produced  on  leaves,  stems  and  fruit.  The   scabs  are  grey  or  pinkish  at  first,  becoming  darker  as  they  age.  The  scabs  join  together,  and   their  centres  become  depressed.  Old  scab  lesions  have  a  rough  surface,  and  become  cracked   and  fissured.  Leaves  become  stunted,  wrinkled  or  puckered,  with  irregular  torn  margins.  

Spores are  produced  in  the  scabs  and  spread  in  wind  and  rain  splash.  Insects  may  also  spread   them.  Spread  over  long  distances  is  on  infected  nursery  plants,  and  on  fruits.  The  spores  need   a  wetting  period  of  4  hours  for  germination  and  infection  to  occur   The  leaves,  twigs  and  fruit  are  infected  when  they  are  young,  becoming  resistant  to  infection   when  full  size.  Fruit  is  susceptible  to  infection  until  3  cm  diameter.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  inspection   Look  for  the  raised  scabs  on  leaves,  twigs  and  fruit.  On  young  leaves  they  are  surrounded  by  a   bright  yellow  margin.  Look  for  twisted,  out-­‐of-­‐shape  leaves.    

Management CULTURAL  CONTROL   The  following  should  be  done:   • Establish  nurseries  for  production  of  rootstocks  and  budwood  at  distance  from  commercial   orchards  where  the  disease  may  be  present;   • Prune  trees  regularly  to  keep  the  canopy  open  and  free  of  deadwood;  this  is  to  remove   sources  of  spores  and  to  improve  air  movement.     CHEMICAL  CONTROL   Fungicides  should  be  applied  to  plants  in  nurseries  at  the  beginning  of  the  leaf  flush  to  prevent   infection  leading  to  stunted,  bushy  plants  that  are  difficult  to  bud.  Copper  (copper  oxychloride)   or  chlorothanonil  (Bravo)  are  suitable  choices.       Treating  mature  lemon  trees  is  not  recommended.  They  produce  multiple  crops,  meaning  that   fruit  forms  throughout  the  year  and  several  spray  treatments  would  be  required,  especially  in   the  high  rainfall  of  Solomon  Islands.  Such  treatments  are  unlikely  to  be  economic.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Broad Mite  

Extension Fact  Sheet  

49

Common  names:  Broad  mite,  Chilli  mite.  Note,  mites  are  not  insects;  they  are  related  to   spiders,  and  have  eight  legs   Scientific  name:  Polyphagotarsonemus  latus.   Hosts:  Chilli,  pepper.  This  is  a  common  mite  worldwide,  infesting  many  crops.  It  is  possible  that   additional  crops,  e.g.,  bean,  eggplant,  papaya,  and  tomato  are  attacked  in  Solomon  Islands,  but   have  yet  to  be  recorded.    

Damage The  mite  causes  a  common  problem  on  chilies  and  bell  pepper  in  Solomon  Islands.  The   symptoms  -­‐  distorted,  crinkled,  young  leaves  and  stunting  -­‐  look  as  if  they  have  a  virus   infection  or,  perhaps,  suffering  the  effects  of  herbicide  damage  (photo,  above).  Later,  there   may  be  flower  drop,  distorted  fruits,  loss  of  yield  and  death  of  the  plants.    

Biology and  Life  Cycle   The  mites  infest  the  youngest  leaves  of  the  bud;  they  are  too  small  (less  than  0.25  mm)  to  be   seen  with  the  eye,  and  a  microscope  or  powerful  hand  lens  is  needed.       The  eggs  are  laid  singly  on  the  underside  of  the  leaves  or  fruit.  There  are  larval  (which  has  6   legs)  and  pupal  stages  before  the  adults  (which  have  8  legs)  are  formed.  Whereas  the  larvae   feed  close  to  where  the  eggs  were  laid,  the  adults  migrate  to  the  young  leaves  to  feed.  The   males  are  yellowish  brown  whereas  the  females  are  yellowish  green.  The  life  cycle  takes  a   week  or  less.       The  outer  cells  of  the  leaf  are  damaged  by  the  mouthparts  of  the  mites  so  that  they  can  suck   up  the  sap.  The  result  is  that  the  leaves,  apart  from  becoming  distorted,  are  bronzed,  stiff,  and   rolled  under  at  the  margins.  Dieback  is  also  a  common  result  from  the  mites  infesting  chilies   and  bell  peppers.   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S     Broad  mites  spread  by  walking  short  distances;  they  are  spread  over  long  distance  by  wind  as   well  as  on  the  bodies  of  insects.    

Detection and  Inspection   Look  for  the  distorted,  stiff,  discoloured  leaves,  on  stunted  plants  showing  dieback  and  early   death.  

Management In  many  parts  of  the  world,  predatory  mites  control  broad  mites,  but  the  situation  in  Solomon   Island  is  unknown.    

CULTURAL CONTROL   Avoid  planting  new  crops  next  to  those  already  infested  with  mites,  otherwise  the  mites   will  spread  to  the  new  crop  at  an  early  age,  and  plants  may  become  severely  damaged;   • Avoid  planting  new  crops  downwind  from  those  infested  with  mites,  as  the  mites  will   spread  to  the  new  crop  on  the  wind;   • When  infestations  are  severe,  pull  out  the  plants,  burn  them,  and  plant  a  new  crop.     CHEMICAL  CONTROL   •

Miticides are  available  for  the  control  of  broad  mite,  but  mostly  these  chemicals  are  not   available  in  Solomon  Islands.  The  best  is  abamectin,  a  compound  derived  from  the  soil   bacterium,  Streptomyces  spp.  Other  chemicals  that  are  affective  are  difocol,  sulfur  and   dimethoate  (Rogor).      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Giant African  Snail  

Extension Fact  Sheet  

50

Common  name:  Giant  African  snail   Scientific  name:  Lissachatina  fulica,  previously  known  as  Achatina  fulica.   Hosts:  Usually,  the  snail  eats  rotten  vegetation  and  animal  wastes;  however,  a  wide  range  of   vegetables,  ornamentals  and  tree  crops  are  also  eaten.      

Damage The  snail  attacks  more  than  500  types  of  plants,  but  it  prefers  breadfruit,  cassava,  cocoa,   papaya,  peanut,  rubber  and  most  species  of  legumes  and  cucurbits.  Cuttings  and  seedlings  are   especially  vulnerable.  Damage  is  greatest  when  outbreaks  first  occur  in  a  new  area.  Population   explosions  result  in  hundreds  of  snails  per  square  metre.     The  rat  lungworm  parasitises  the  snail,  and  if  the  snails  are  not  cooked  thoroughly  before   being  eaten  by  human  beings,  the  lungworm  can  cause  meningitis.     The  economic  impact  of  the  snail  is  unclear.  When  first  introduced,  populations  soar,  but   population  explosions  are  often  followed  by  population  crashes.  It  then  becomes  a  minor  pest   of  agriculture  and  human  health.  But  it  does  have  an  impact  on  the  environment:  a)  dead   snails  are  places  where  flies  breed;  and  b)  it  causes  loss  of  biodiversity:  native  plants  are  eaten,   and  it  competes  with  local  snails.  

Biology and  Life  Cycle   The  snails  vary  considerably  in  size  and  colour.  Some  grow  to  15  cm  in  length  and  5-­‐8  cm  wide,   whereas  others  grow  only  to  6.5  cm  in  length.  Commonly,  the  shells  are  light  brown  with   darker  brown  and  cream  bands.       The  snail  feeds  at  night  or  during  the  day  when  the  weather  is  overcast  and  rainy;  it  avoids  the   sun  by  sheltering  under  stones,  logs  or  in  crevices.  If  dry  weather  lasts,  the  snail  seals  the   opening  of  the  shell  awaiting  a  return  to  favourable  conditions.         Each  snail  has  male  and  female  sex  organs  (hermaphrodite),  but  reproduction  requires  cross-­‐ fertilization.  Eggs  are  first  laid  when  females  are  about  6  months’  old.  The  eggs  are  cream,   about  5  mm  diameter,  laid  below  the  soil  surface  or  on  the  sides  of  logs,  in  batches  of  200  to   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   300.  The  eggs  hatch  within  1  to  2  weeks.  Up  to  a  1000  eggs  are  laid  each  year  and  snails  live  for   up  to  5  years.       The  snails  can  travel  up  to  50  m  in  a  night,  moving  on  the  slime  made  by  the  soft  part  known   as  the  ‘foot’.  Long  distance  travel  is  by  human  beings:  the  eggs  and  young  snails  may  be  in  soil   of  pot  plants  or  sawdust;  the  adult  snails  may  be  taken  and  raised  for  food,  kept  as  pets,  or   transported  as  hitchhikers  on  boats  or  land  vehicles.    

Detection and  Inspection   Conduct  surveys  at  night  looking  for  signs  of  rasping  on  leaves  or  defoliated  plants,  ribbon-­‐like   excreta  and  slime  trails.  Look  for  snails  much  larger  than  any  indigenous  ones  of  Solomon   Islands;  look  for  the  typical  colour  banding  on  the  shell.  

Management NATURAL  ENEMIES   Predatory  snails,  such  as  Euglandina  rosea  and  Gonaxis  quadrilateralis,  and  flatworms,  e.g.,   Platydemus  manokwari,  have  been  introduced  to  control  the  snail,  but  the  effects  have  been  a   disaster  for  local  snail  populations.  Environmental  impact  studies  are  essential  before  the   introduction  of  these  predators  because  of  their  non-­‐specific  nature.       Ducks  will  attack  the  snail;  they  are  the  only  type  of  livestock  that  will  do  so.  Although   population  explosions  can  be  immensely  destructive  immediately  after  spread  to  a  new  area,   invariably  snail  population  will  decline.  The  problem  is  how  to  deal  with  the  snail  until  that   happens,  which  may  be  months  or  years.    

CULTURAL CONTROL   Cultural  control  is  important.  The  following  should  be  done:     • Make  a  strip  of  bare  earth  about  1.5  m  wide  around  cultivated  areas.  Bands  of  sand  are   also  effective;   • Collect  the  snail  regularly,  preferably  by  mobilising  the  community  –  schools  in  particular,   then  bury  the  snails  or  feed  them  to  pigs  after  boiling  for  an  hour;   • Conduct  awareness  campaigns:  a)  snails  should  not  be  kept  as  pets;  b)  they  are  a  threat  to   human  health;  and  c)  community  action  is  needed  to  control  them.    

CHEMICAL CONTROL   The  usefulness  of  metaldehyde  or  methiocarb  (pellets  containing  1.5-­‐1.8  %  of  poison)  over   large  areas  is  not  encouraged,  although  they  are  probably  effective  in  the  cultivation  of  small   areas  of  vegetables.  Take  care  to  prevent  livestock,  pets  and  children  from  eating  them:  put   the  pellets  in  tins  or  bamboos  in  the  evening  and  collect  them  in  the  morning.  Chemical   control  needs  to  be  combined  with  cultural  methods  to  be  effective.  Poisoned  snails  should   never  be  fed  to  pigs  or  other  livestock.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sooty Mould  Fungi  

Extension Fact  Sheet  

51

Common  name:  Sooty  mould     Scientific  names:  A  number  of  sooty  mould  fungi  have  been  identified  in  Solomon  Islands:   Aithaloderma  citri  (grapefruit)   Capnodium  mangiferum  (mango)   Capnodium  sp.  (pawpaw)   Chaetasbolisia  microglobulosa  (chilli)   Chaetothyrium  setosum  (coconut,  kongkong  taro)   Limacinula  samoenesis  (coconut)   Microxiphium  spp.  (chilli,  coconut,  oil  palm)   Trichomerium  spp.  (coconut,  oil  palm)   Tripospermum  fructigenum,  (Pometia  pinnata)   Tripospermum  gardneri  (oil  palm,  cocoa)   Tripospermum  sp.  (chilli)   Triosporiopsis  sp.  (pawpaw)     Hosts:  Many  plants  develop  sooty  moulds  when  colonised  by  insects  that  produce  honeydew   (photos  below  are:  left,  soursop;  right,  coconut).  The  sooty  mould  fungi  recorded  in  Solomon   Islands  and  the  host  plants  are  given  above.  Most  were  recorded  from  living  leaves.      

Damage The  fungi  grow  on  the  sugary  substances  that  are  produced  by  insects  –  mostly,  aphids,  scale   insects  (photo,  right:  remains  of  the  infestation  on  upturned  leaf  –  lower  right  corner),  and   whiteflies  -­‐  as  they  suck  the  sap  of  leaves.  The  secretions  are  known  as  honeydew.       The  insects  that  produce  honeydew  are  the  real  problem.  They  cause  direct  damage  by  sucking   plant  sap,  and  often  cause  poor  growth,  and  indirect  damage  by  encouraging  sooty  moulds.   The  fungi  do  little  direct  harm  to  the  plant,  apart  from  blocking  sunlight  and  causing  the  leaves   to  yellow.  They  do  not  infect  the  leaves,  and  rarely  stunt  the  plants.      

  AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Biology and  Life  Cycle   Insect  populations  increase  rapidly  when  ants  protect  them  from  their  natural  predators  and   parasites.  Large  populations  of  insects  mean  large  amounts  of  honeydew,  and  heavy  coverage   of  leaves,  and  other  parts,  by  sooty  mould  fungi.  

Detection and  Inspection   Look  for  sooty  mould  on  new  growth  and  leaves,  since  the  insects  involved  in  sooty  mould   growths  prefer  soft  tissue.  

Management All  the  methods  used  for  treating  sooty  mould  are  aimed  at  controlling  the  insects  that  secrete   the  honeydew.  Without  honeydew,  there  can  be  no  sooty  mould.  However,  the  insects  may  be   protected  from  their  natural  predators  and  parasites  by  ants,  so  removing  the  ants  should  be   the  first  step,  if  they  are  present.    

CULTURAL CONTROL   • •

If ants  are  present,  kill  them  with  boiling  water,  without  damaging  the  crop  plants.   Without  the  ants,  predators  and  parasites  will  bring  about  natural  control;   For  trees,  prune  low  branches  and  remove  weeds  to  stop  ants  reaching  the  leaves.    

CHEMICAL CONTROL   •

Use soap  sprays  (5  tablespoons  of  soap  in  4  litres  water),  or  white  oil  to  kill  the  sap-­‐ suckering  insects.  These  sprays  work  by  blocking  the  breathing  holes  of  insects  causing   suffocation  and  death.  Spray  the  undersides  of  leaves:  the  oils  must  contact  the  insects.     Use  white  oil  (petroleum  jelly),  which  can  be  obtained  as  a  commercial  product  or  made  by   mixing  together:  1  cup  cooking  oil;  2  cups  water;  1  teaspoon  dishwashing  liquid.  Dilute  the   mixture  at  3  teaspoons  per  half  a  litre  of  water  and  spray  on  the  infested  leaves.  The   addition  of  malathion  is  useful  against  scales  insects;   To  kill  ants  use  synthetic  pyrethroids  (for  example,  lambda  cyhalothrin  or  cypermethrin);   these  insecticides  may  also  be  tried  against  scale  insects  as  they  are  likely  to  be  effective   against  the  crawlers  –  crawlers  are  the  young  active  nymphs  which  spread  infestations  to   new  plants  or  new  gardens.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

White Peach  Scale  

Extension Fact  Sheet  

52

Common  name:  White  peach  scale   Scientific  name:  Pseudaulacaspis  pentagona.   Hosts:  Chilli,  pepper,  sliperi  kabis,  cassava.  It  has  also  been  found  causing  heavy  infestations  on   paper  mulberry  (Broussonetia  sp.)  on  Guadalcanal.  Worldwide,  there  are  many  other  hosts.    

Damage The  scale  is  most  often  seen  in  large  numbers  on  the  bottom  of  stems;  there  are  often  so   many  that  farmers  think  a  white  fungus  affects  the  plants  (photo,  right).       The  scale  feeds  on  plant  sap,  and  infestations  cause  leaves  to  yellow  with  a  loss  of  healthy   growth.  Fruit  size  may  be  reduced  and  premature  drop  is  likely.  Heavy  infestations  can  result   in  stunting  (cassava),  and  the  death  of  branches  and  dieback  (chilli  and  bell  pepper).  Severe   infestations  on  cassava  have  been  reported  from  the  weather  coast  of  Guadalcanal.  

Biology and  Life  Cycle   The  life  cycle,  which  lasts  about  45  days,  is  complex.  Females  are  covered  by  a  roughly  circular   scale  (photo,  left),  about  2-­‐2.5  mm  across;  beneath  the  scale  is  the  insect  itself,  0.8-­‐0.9  mm   long,  pink  to  yellow,  and  without  legs.  Egg  laying  begins  2  weeks  after  mating,  and  about  100   eggs  are  laid  over  8-­‐9  days.  The  first  eggs  laid  become  female,  those  later,  male.  Crawlers   emerge  after  3-­‐4  days.     The  crawlers  have  three  pairs  of  legs  and  prominent  antennae.  The  females  are  more  active   and  wander  further  than  the  males.  After  about  12  hours  they  settle  down  to  feed,  and  go   through  two  moults  before  they  become  adult.  The  males  stay  around  the  mother,  moulting   five  times,  but  as  adults  last  only  1  day.  They  are  orange  with  wings,  eyes,  legs,  long  antennae,   but  no  mouthparts;  they  do  not  feed.  Their  task  is  to  find  females  and  mate,  attracted  by   chemicals  (pheromones)  produced  by  them.       Spread  is  by  crawlers  on  the  wind,  and  infested  cuttings.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

READ INSTRUCTIONS  BEFORE  USING  PESTICIDES

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  the  heavy  infestations  that  occur  as  thick  crusts  on  stems  or  tree  trunks.  The  leaves   and  fruits  are  not  usually  infested.  The  large  white  colonies  of  females  and  males  that  make  up   a  heavy  infestation  are  easy  to  recognize.  

Management NATURAL  ENEMIES   Species  of  ladybird  beetles  and  lacewings  are  known  to  feed  on  white  peach  scale  in  other   parts  of  the  world  and  probably  these  insects  do  the  same  in  Solomon  Islands.  Encarsia   diaspidicola,  a  wasp,  has  been  successfully  released  in  Samoa  and  more  recently  in  Hawaii  with   good  results.    

CULTURAL CONTROL   • • •

Cut out  stems  of  plants  infested  by  white  peach  scale  and  burn  them;   Do  not  plant  cuttings  from  plants  infested  with  white  peach  scale;   Avoid  planting  new  crops  downwind  from  those  infested  with  white  peach  scale,  as  the   crawlers  will  spread  to  the  new  crop  on  the  wind.  

CHEMICAL CONTROL   Insecticides  should  be  avoided,  unless  control  by  natural  enemies  is  ineffective.  Note,  too,   insecticides  are  not  always  effective  against  females;  they  live  under  a  protective  scale.       • Use  soap  sprays  (5  tablespoons  of  soap  in  4  litres  water),  or  white  oil  to  kill  the  sap-­‐ suckering  insects.  These  sprays  work  by  blocking  the  breathing  holes  of  insects  causing   suffocation  and  death.  Spray  the  undersides  of  leaves:  the  oils  must  contact  the  insects.     • Use  white  oil  (petroleum  jelly),  which  can  be  obtained  as  a  commercial  product  or  made  by   mixing  together:  1  cup  cooking  oil;  2  cups  water;  1  teaspoon  dishwashing  liquid.  Dilute  the   mixture  at  3  teaspoons  per  half  a  litre  of  water  and  spray  on  the  infested  leaves.  The   addition  of  malathion  is  useful  against  scales  insects;   • To  kill  ants  use  synthetic  pyrethroids  (for  example,  lambda  cyhalothrin  or  cypermethrin);   these  insecticides  may  also  be  tried  against  scale  insects  as  they  are  likely  to  be  effective   against  the  crawlers  –  crawlers  are  the  young  active  nymphs  which  spread  infestations  to   new  plants  or  new  gardens.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

READ INSTRUCTIONS  BEFORE  USING  PESTICIDES

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Red Sweetpotato  Beetle  

Extension Fact  Sheet  

53

Common  names:  Red  sweetpotato  beetle,  Sweetpotato  red  leaf  beetle                                                   Scientific  name:  Monolepta  semiviolacea.     Hosts:  Sweetpotato  and  kangkong  (Ipomoea  aquatica),  and  related  Ipomoea  species  (plants  in   the  morning  glory  family).  The  beetle  occurs  commonly  on  other  crops,  but  does  not  appear  to   feed  on  them.      

Damage Adult  beetles  (photo,  right)  feed  on  leaves,  chewing  holes,  especially  in  the  middle  of  the  leaf   (photo,  left).  The  damage  to  young  plants  can  delay  establishment,  early  growth  and  crop   maturity.  Damage  also  occurs  to  flowers.       The  larvae  probably  damage  roots  and  stems,  but  evidence  of  this  has  not  been  looked  for  in   Solomon  Islands.  Such  damage  allows  entry  of  other  organisms,  fungi  and  nematodes   especially.  

Biology and  Life  Cycle   The  biology  and  life  cycle  has  not  been  studied  for  M.  semiviolacea.  The  following  information   is  from  a  similar  pest  species  in  Australia.       Eggs  are  laid  under  the  soil  surface.  The  white  cylindrical  grubs  or  larvae  feed  on  roots  and   pupate  in  the  soil.  The  life  cycle  takes  about  2  months.  There  may  be  three  to  four  generations   a  year.  If  larval  populations  in  the  soil  are  high,  the  emerging  beetles  will  form  a  swarm  that   migrates  into  nearby  crops.  

Detection and  Inspection   Look  for  red  oval  beetles,  about  6  mm  long,  on  the  leaves  and  flying  between  them.  They  have   a  small  black  triangular  spot  at  the  base  of  the  wing  cases,  and  are  black  underneath.  They  are   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   often  seen  in  groups  on  young  and  old  leaves.  Look  for  numerous  small  holes  in  the  leaves   between  the  veins.  Adults  are  strong  fliers,  and  quickly  take  to  the  wing  when  disturbed.     A  similarly  coloured  leaf  beetle,  Aulacophora,  is  entirely  red.  It  also  has  a  groove  across  the   base  of  the  thorax  -­‐  the  part  behind  the  head.  By  contrast,  Monolepta  has  a  smooth  thorax.   Also,  Aulcophora  is  larger  than  Monolepta.  (See  Fact  Sheet  no.  40  for  Aulcophora.)  

Management There  is  little  known  about  the  natural  control  of  the  Red  sweetpotato  beetle.  There  are  no   known  predators  or  parasites  effective  against  high  populations.  The  beetles  contain  chemicals   that  visual  predators  (birds  and  lizards)  do  not  like,  and  they  avoid  them.  The  bright  colours  of   this  beetle  warn  predators  that  they  are  distasteful.    

RESISTANT VARIETIES   •

None known,  but  fast-­‐growing  varieties  are  more  likely  to  outgrow  the  damage  caused  by   the  beetles.  Look  for  differences  in  damage  between  varieties.  

CULTURAL CONTROL   • • • •

Avoid planting  new  crops  next  to  those  already  infested  with  the  beetles;     Harvest  the  affected  crop,  collect  and  destroy  the  vines,  and  then  plant  a  new  crop;   Provide  conditions  for  healthy  rapid  plant  growth,  especially  for  cuttings;  these  may   include  manures,  mulches,  commercial  fertilizers,  as  well  as  adequate  water;   In  the  early  morning  or  evening,  it  is  possible  to  catch  the  beetles  in  flight;  this  is  a  useful   control  method  in  small  gardens.  Perhaps  a  game  for  children!  

CHEMICAL CONTROL   •

• •

Ashes may  be  effective  against  Red  sweetpotato  beetle.  Apply  them  to  the  crop  as  soon  as   the  pest  is  seen;  do  not  wait  until  the  population  is  high.  (See  Fact  Sheet  no.  56d  on  PDPs,   Plant  Derived  Pesticides,  for  details  of  how  to  make  and  apply  the  ash.)  Alternatively,   add  ½  cup  of  wood  ash  and  ½  cup  of  lime  in  4  litres  water;  leave  to  stand  for  some  hours;   strain;  test  on  few  infested  plants  first  to  make  adjustment  of  the  strength  before  going   into  large-­‐scale  spraying.   Use  synthetic  pyrethroid  insecticides,  such  as  lambda  cyhalothrin  or  permethrin.  The   choice  of  chemical  is  important:  use  those  that  are  least  persistent  in  the  environment,   and  have  low  toxicity  against  bees;   As  infestations  are  often  patchy,  consider  spot  spraying  or  perimeter  spraying  where   numbers  are  highest,  leaving  most  of  the  crop  unsprayed;   Derris  (rotenone)  may  be  effective  against  the  beetle.  A  variety  of  Derris,  brought  many   years  ago  from  Papua  New  Guinea,  may  be  effective  as  a  spray.  It  contains  rotenone,  an   insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for  evaluation  by  growers.  Contact   those  organisations  for  plants  to  test.  

     

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

potato Tortoise  Beetle  

Extension Fact  Sheet  

54

Common  names:  Sweetpotato  tortoise  beetle;  sometimes  known  as  Golden  tortoise  beetle                                   Scientific  name:  Cassida  papuana.   Hosts:  Sweetpotato,  kangkong  (Ipomoea  aquatica),  and  related  Ipomoea  species  (plants  in  the   morning  glory  family).  Possibly,  the  beetles  feed  on  crops  and  weeds  in  other  families.      

Damage   Adults  feed  on  leaves,  making  small  to  medium-­‐size  holes  (photo,  left).  The  larvae  at  first  eat   the  leaf  surface;  latter  they  eat  their  way  through  the  leaf.  The  effect  on  storage  root  yield  is   not  known  in  Solomon  Islands,  but  it  is  unlikely  to  be  large.  

Biology and  Life  Cycle   The  oval  eggs  (1-­‐2  mm  long)  are  laid  individually  on  the  leaves  in  a  small  papery  parcel.  The   larvae  have  spines,  and  an  anal  fork.  The  anal  fork  is  made  up  of  long  spines  near  the  tip  of  the   abdomen,  and  these  hold  the  old  skins  -­‐  which  are  not  shed  completely  -­‐  mixed  with  excreta   (faeces  or  droppings).  The  ‘tail’  of  old  skins  is  carried  over  the  back  of  the  body,  and  can  be   moved  about  by  the  anal  fork,  probably  to  deter  predators.  The  larvae  pass  through  five   moults,  before  a  pupal  stage  develops.  The  pupae  are  attached  by  the  tail  end  to  the   underside  of  the  leaf.       The  adults  are  about  5  mm  diameter,  oval  and  slightly  flattened  and  squared  at  the  shoulders   (photo,  right).  The  head  and  appendages  of  the  adult  are  mostly  hidden  by  transparent  parts   of  the  thorax  and  the  wing  covers.  

Detection and  Inspection   Look  for  the  golden  round  beetles,  and  the  clear,  wing  margins  that  cover  most  of  the  head   and  thorax,  and  extend  beyond  the  body,  covering  legs  and  other  appendages.         AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management NATURAL  ENEMIES   Tortoise  beetles  are  attacked  by  (chalcid)  wasps  in  other  countries,  parasitic  flies,  and  lady   beetle  larvae.  It  is  likely  that  these  parasites  and  predators  attack  Tortoise  beetles  in  Solomon   Islands,  but  this  is  not  known  for  certain.  However,  it  is  not  common  for  Tortoise  beetles  to   become  a  serious  pest.  

CULTURAL CONTROL   • • •

Avoid planting  new  crops  next  to  those  already  infested  with  the  beetles;     Harvest  the  infested  crop,  collect  the  vines  and  destroy  them,  and  then  plant  a  new  crop;   Provide  conditions  for  healthy,  rapid  plant  growth,  especially  for  vine  cuttings  after   planting;  these  may  include  manures,  mulches  and/or  commercial  fertilizers,  and  adequate   water;   Remove  weeds  (especially  those  in  the  Convolvulaceae  family)  around  the  gardens  to   reduce  the  beetle  numbers.  

RESISTANT VARIETIES   •

None known,  but  fast-­‐growing  varieties  are  more  likely  to  outgrow  the  damage  caused  by   the  beetles.    

CHEMICAL CONTROL   Ashes  may  be  effective  in  the  control  of  the  Tortoise  beetle.  Apply  them  to  the  crop  as  soon  as   the  pest  is  seen;  do  not  wait  until  the  population  is  high.  (See  Fact  Sheet  no.  56  on  PDPs,  Plant   Derived  Pesticides,  for  details  of  how  to  make  and  apply  the  ash.)     • Ashes  may  be  effective  against  the  Sweetpotato  tortoise  beetle.  Apply  them  to  the  crop  as   soon  as  the  pest  is  seen;  do  not  wait  until  the  population  is  high.  (See  Fact  Sheet  no.  56d   on  PDPs,  Plant  Derived  Pesticides,  for  details  of  how  to  make  and  apply  the  ash.)   Alternatively,  add  ½  cup  of  wood  ash  and  ½  cup  of  lime  in  4  litres  water;  leave  to  stand  for   some  hours;  strain;  test  on  few  infested  plants  first  to  make  adjustment  of  the  strength   before  going  into  large-­‐scale  spraying.   • Use  synthetic  pyrethroid  insecticides,  such  as  lambda  cyhalothrin  or  permethrin.  The   choice  of  chemical  is  important:  use  those  that  are  least  persistent  in  the  environment,   and  have  low  toxicity  against  bees.     • Derris  (rotenone)  may  be  effective  against  the  beetle.  A  variety  of  Derris,  brought  many   years  ago  from  Papua  New  Guinea,  may  be  effective  as  a  spray.  It  contains  rotenone,  an   insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for  evaluation  by  growers.  Contact   those  organisations  for  plants  to  test.              

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S

Sweetpotato Little  Leaf  

Extension Fact  Sheet  

55

Common  names:  Sweetpotato  little  leaf,  Sweetpotato  witches’  broom   Scientific  name:  Candidatus  Phytoplasma  aurantifolia.   Hosts:  Sweetpotato  and  probably  wild  Ipomoea  species,  but  the  disease  has  not  been  seen  on   wild  hosts  in  Solomon  Islands.    

Damage Severe  outbreaks  of  the  disease  have  occurred  in  Solomon  Islands  (and  Papua  New  Guinea)  in   areas  with  low  rainfall,  and  where  there  is  a  distinct  dry  season  -­‐  Guadalcanal  Plains  and  Santa   Ana.  Yield  losses  of  30-­‐90%  have  been  reported.     The  disease  also  causes  stunting  of  the  root  system,  and  affected  plants  produce  few,  if  any,   storage  roots.      

Biology and  Life  Cycle   One  of  the  first  symptoms  of  the  disease  is  a  yellowing  of  the  small  veins,  so  that  they  are   clearly  seen  as  a  network  throughout  the  leaf  (photo,  right).  This  is  followed  by  the   development  of  side  shoots,  which  are  normally  dormant,  giving  the  vines  a  bushy  appearance   (photo,  left).  New  leaves  on  these  shoots  become  progressively  smaller,  until  they  are  about   an  eighth  the  size  of  healthy  leaves.  Also,  the  leaves  change  to  a  light  green  and  the  shoots  are   generally  more  erect  than  normal.     Phytoplasmas  (before  they  were  called  mycoplasma-­‐like  organisms,  or  MLOs)  are  bacteria-­‐like,   single  celled  organisms.  They  are  obligate  parasites,  confined  to  the  phloem  of  their  hosts  and   transmitted  by  phloem-­‐feeding  insects.  In  this  case,  the  phytoplasmas  are  spread  by   leafhoppers,  Orosius  lotophagorum  ryukyuensis.  Phytoplasmas  reproduce  asexually  by   budding.     The  leafhoppers  acquire  the  phytoplasmas  after  feeding  on  infected  plants  for  several  hours  or   days.  After  a  period  of  approximately  20  days  they  are  then  able  to  transmit  the  phytoplasmas   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with   support   from   IPPSI:   Improved   Plant   Protection   in   Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S to  healthy  plants  as  they  feed.  Once  a  leafhopper  becomes  infected  with  phytoplasmas  it  can   transmit  it  for  the  rest  of  its  life.     A  number  of  wild  species  of  Ipomoea  are  hosts  of  the  phytoplasma.  However,  it  is  not  known   how  important  they  are  in  outbreaks  and  spread  of  the  disease.  

Detection and  Inspection   Look  for  the  yellowing  of  the  veins,  which  is  the  first  symptom,  then  the  production  of  many   shoots  with  small  leaves,  giving  the  plant  a  typical  bushy  appearance.  

Management CULTURAL  CONTROL   Cultural  control  measures  are  important  to  reduce  the  disease:   • Remove  plants  with  signs  of  the  disease  as  soon  as  they  appear,  and  burn  them;   • Little  leaf  is  spread  mostly  in  infected  planting  material.  If  possible,  take  planting  material   from  gardens  where  the  disease  has  not  been  seen;   • If  that  is  not  possible,  carefully  select  planting  material  from  plants  that  are  free  of  the   disease.  Look  for  symptoms  after  planting;   • If  that  is  not  possible,  collect  disease-­‐free  cuttings  from  neighbours,  if  their  gardens  are   healthy.    

RESISTANT VARIETIES   •

No resistance  was  found  among  more  than  200  varieties  screened  in  Solomon  Islands,   although  one  variety,  WV5,  had  greater  resistance  than  others.  See  MAL  for  a  source  of   planting  material  of  this  variety.  It  was  reimported  from  SPC,  Fiji.    

CHEMICAL CONTROL   Chemical  control  should  only  be  considered  under  exceptional  circumstances.  In  dry  times,  the   population  of  the  leafhopper  may  become  very  high,  and  the  disease  may  reach  epidemic   levels.  This  has  occurred  in  Santa  Ana.  Treat  crops  with  an  insecticide,  but  also  remove   infected  plants  to  take  out  the  source  of  the  disease.  Use  the  following:   • Synthetic  pyrethroid  insecticides,  such  as  lambda  cyhalothrin  or  permethrin.  The  choice  of   chemical  is  important:  use  those  that  are  least  persistent  in  the  environment,  and  have   low  toxicity  to  bees.     • Derris  (rotenone)  may  be  effective  against  the  leafhopper  that  spreads  Sweet  potato  little   leaf.  A  local  variety  of  Derris  that  has  a  high  concentration  of  rotenone  is  being  multiplied   by  MAL  and  the  Kastom  Gaden  Association.  The  variety  came  originally  from  Papua  New   Guinea.  [See  these  organisations  for  cuttings,  and  the  method  of  using  it.]    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with   support   from   IPPSI:   Improved   Plant   Protection   in   Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

56a

Extension Fact  Sheet  

Natural pesticides  against  insects   General  instructions   •

Select fresh,  healthy  plant  parts  to  use  as  pesticides;  reject   plants  with  moulds  on  them;  

Keep plant  extracts  away  from  children  and  house  pets    

Dry plant  parts  properly  for  future  use.  Keep  in  an  airy   container  (no  plastic  containers)  in  a  shady  place;  

Harvest all  mature  and  ripe  fruits  on  trees  before  spraying  

Always test  the  plant  extract  on  a  few  infested  plants   before  large-­‐scale  spraying  

Do not  use  household  cooking  tools  for  preparing  plant   extracts,  or  containers  used  for  drinking  water.  Clean  all   tools  well  after  using  them;  

Wash your  hands  after  handling  the  plant  extract  and   wash  your  clothes,  too  

Avoid contact  with  crude  extracts  during  preparation;   wear  protective  clothing  when  applying.  

See other  fact  sheets  (56b,c,d)  for  how  to  prepare  plant   extracts.  

PLANT PESTICIDE  AGAINST:  non-­‐sucking  insects  (chew,  bite)   Control  

Ants

Beetles

Caterpillars

Grasshoppers

ASH

CHILLI

DERRIS

FU’U

Possibly a  rat  poison,  but  may  also  be  useful  as  an   insecticide  

GARLIC

GLIRICIDIA

HORTICULTURAL OIL  

HOT WATER  

MARIGOLD

Insect repellent,  and  when  used  as  a  cover  crop  reduces   root  knot  nematodes  

NEEM

PAPAYA

SOAP

SOURSOP

TOBACCO

PLANT PESTICIDE  AGAINST:  sucking  insects   CONTROL  

Aphids

Mealybugs

Planthoppers

Scales

Spider mites  

Thrips

Whiteflies

ASH

CHILLI

DERRIS FU’U  

Possibly a  rat  poison,  but  may  also  be  useful  as  an  insecticide  

GARLIC

GLIRICIDIA

HORTICULTURAL OIL  

HOT WATER   MARIGOLD  

Insect repellent,  and  when  used  as  a  cover  crop  reduces  root  knot  nematodes  

NEEM

PAPAYA

SOAP

SOURSOP

TOBACCO

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

56b

Extension Fact  Sheet  

Preparing natural  pesticides  1   See  Fact  Sheet  56a  for  more  information  on  target  pests.  

General instructions   •

Select fresh,  healthy  plant  parts  to  use  as   pesticides;  reject  plants  with  moulds  on  them  

Keep plant  extracts  away  from  children  and   house  pets    

Dry plant  parts  properly  for  future  use.  Keep  in   an  airy  container  (no  plastic  containers)  in  a   shady  place.  

Harvest all  mature  and  ripe  fruits  on  trees  before   spraying  

Do not  use  household  cooking  tools  for   preparing  plant  extracts,  or  containers  used  for   drinking  water.  Clean  all  tools  well  after  using   them  

Always test  the  plant  extract  on  a  few  infested   plants  before  large-­‐scale  spraying  

Wash your  hands  after  handling  the  plant  extract   and  wash  your  clothes,  too  

See other  fact  sheets  (56a,c,d)    for  more  information   on  natural  pesticides.

Avoid contact  with  crude  extracts  during   preparation;  wear  protective  clothing  when   applying  

Chilli

Neem

CHILLI: active  against  ants,  aphids,  caterpillars,   mealybugs  

Soursop

Tobacco

Grind them  into  a  fine  powder  

Mix the  powder  in  12  litres  water  and  soak   overnight   Strain,  and  add  4  teaspoons  soap  

Take one  cup  dry  or  2  cups  fresh  chillies  

Smash to  a  fine  paste  

Put into  bucket  with  1  litre  water  and  rub  with   hands  (cover  hands  with  plastic  bag)  

Soak of  at  least  1  hour;  squeeze  and  strain  

SOURSOP OR  CUSTARD  APPLE:  active  against   aphids,  caterpillars  (diamond  back  moth),   planthoppers,  grasshoppers  

Make up  to  1  litre  with  water  

Add 1  teaspoon  of  soap  

Take 500  g  of  fresh  leaves;  boil  leaves  in  2  litres   water  until  water  is  reduced  to  0.5  litre  

Dilute to  10  litres  with  water  

Strain, and  add  10  teaspoon  soap  

NEEM: active  against  caterpillars,  grasshoppers,  and   many  more;  also  fungi  and  nematodes   For  leaves:  

Also: •

Take two  handfuls  of  seeds  and  grind  into  a  fine   powder  

Mix with  4  litres  of  water  and  soak  overnight;   strain,  and  add  4  teaspoons  soap  

Put 1  kg  of  leaves  plus  5  litres  water  in  a  bucket   and  leave  overnight  

Remove the  leaves,  retain  the  water  and  pound   the  leaves  

Squeeze the  leaves  and  add  the  5  litres  of  water   used  for  soaking  them  overnight  

more

Add about  20  ml  of  diluted  soapy  water  and  use  

Smash 5  large  leaves  

For mature  seeds:  

TOBACCO: active  against  caterpillars,  aphids,  and  

Add 1  litre  water  and  leave  overnight  

Wash and  remove  the  husk  and  dry  

Make up  to  2  litres  with  water  

Take 12  handfuls  of  dry  seeds  (or  use  500  grams   per  10  litres  water)  

Strain, and  add  4  teaspoons  of  soap  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

56c

Extension Fact  Sheet  

Preparing natural  pesticides  2   See  Fact  Sheet  56a  for  more  information  on  target  pests.  

General instructions   •

Select fresh,  healthy  plant  parts  to  use  as   pesticides;  reject  plants  with  moulds  on  them;  

Keep plant  extracts  away  from  children  and   house  pets;  

Dry plant  parts  properly  for  future  use.  Keep  in   an  airy  container  (no  plastic  containers)  in  a   shady  place;  

Harvest all  mature  and  ripe  fruits  on  trees  before   spraying;  

Do not  use  household  cooking  tools  for   preparing  plant  extracts,  or  containers  used  for   drinking  water.  Clean  all  tools  well  after  using   them;  

Always test  the  plant  extract  on  a  few  infested   plants  before  large-­‐scale  spraying;  

Wash your  hands  after  handling  the  plant  extract   and  wash  your  clothes,  too.  

See other  FS  56c  for  more  information  on  natural   pesticides.

Avoid contact  with  crude  extracts  during   preparation;  wear  protective  clothing  when   applying;  

Garlic

Derris

GARLIC: active  against  caterpillars,  mites,  thrips,  and   possibly  some  fungal  diseases  

Gliricidia

Marigold

GLIRICIDIA: active  against  aphids,  caterpillars,  

whitefly

Scrape 4  garlic  cloves  and  soak  in  small  amount  of   vegetable  oil  

Grind or  pound  0.5  kg  leaves   Soak  overnight  in  water  

Leave overnight  

• •

Make up  to  20  liters  with  water  

Make up  to  2  litres  with  water,  strain,  and  add  4   teaspoons  soap  

Strain, and  add  10  teaspoons  soap  

Also, scrape  4  cloves  in  hot  water;  add  several   ground  chillies,  and  2  tablespoons  pure  soap.  Use   spray  when  water  is  cool  

DERRIS: active  against  caterpillars,  grasshoppers,   aphids,  spider  mites,  plant  hoppers;  beetles   •

Take 2  roots  of  Derris  (20  cm  long  and  as  thick  as   a  small  finger)  and  smash  well  

Note: Gliricidia  is  also  a  rat  poison.  Mix  the  amounts   above  with  boiled  rice.  But  may  need  to  make  up  fresh   ever  day.  Place  the  ‘food’  in  a  bamboo  to  protect  it   from  children,  pets  and  domestic  animals.  Bacterial   action  converts  chemicals  in  the  leaves  to   brodifacoum-­‐like  substances.  

MARIGOLD: active  against  insects  and  is  a  repellent   •

Put roots  in  a  bucket  overnight  and  cover  with   water  

Collect 2.5  kg  leaves/flowers;  pound  and  mix  with   enough  water  to  cover  material  

Filter and  make  up  to  18  litres  water;  Add  soap

Make up  to  2  litres  with  water   Strain,  and  add  4  teaspoons  soap  

PAPAYA: active  against  thrips  

Shake 1  kg  leaves  in  1  litre  water  and  squeeze   through  cloth    

Add 4  litre  soap  solution  (100  g  soap/25  litres   water  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Extension Fact  Sheet  

Preparing natural  pesticides  3  

56d

See Fact  Sheet  56a  for  more  information  on  target  pests.  

General instructions   Do  not  use  household  cooking  tools  for   preparing  plant  extracts,  or  containers  used  for   drinking  water.  Clean  all  tools  well  after  using   them;  

Harvest all  mature  and  ripe  fruits  on  trees  before   spraying;  

Always test  the  plant  extract  on  a  few  infested   plants  before  large-­‐scale  spraying;  

Avoid contact  with  crude  extracts  during   preparation;  wear  protective  clothing  when   applying;  

Wash your  hands  after  handling  the  plant  extract   and  wash  your  clothes,  too.  

Keep plant  extracts  away  from  children  and   house  pets;  

See other  fact  sheets  (56a,b,c)  for  more  information   on  natural  pesticides.

Soap

Hot Water  

SOAP: active  against  scale  insects,  mealybugs  and  

aphids •

Use soap  (pure  soap,  not  detergent)  

5 tablespoons  of  soap  in  4  litres  water;  OR  

2 tablespoons  of  dish  washing  liquid  in  4  litres   water  

HOT WATER:  active  against  ants,  nematodes  in  yams   and  sterilise  nursery  soil   •

ANTS Use  to  destroy  nests,  but  be  careful  not  to   pour  hot  water  onto  the  roots  of  small  plants  that   might  be  growing  close  to  the  nests.  You  will  kill   the  plants!   SOIL  Use  hot  water  to  sterilise  soil:  pour  over  the   soil  that  you  have  placed  in  seed  boxes  or  soil   spread  thinly  on  the  ground  containing  the   nursery  soil   YAM  Use  hot  water  to  kill  nematodes  in  yams   with  dry  rot  before  cutting  and  planting.  Dip   0 whole  yams  in  hot  water  at  51 C  for  10  mins  (use   a  thermometer  and  clock  –  do  NOT  guess)      

Ash

Horticultural Oil  

ASH: active  against  grasshoppers  and  beetles   •

Take ash  from  fire  (make  sure  it  is  cool!)  

Beat to  make  fine  

Put in  coarse  cloth  or  into  a  strainer  

Shake thinly  over  each  leaf  

HORTICULTURAL OIL:  active  against  powdery  mildew   fungi  and  also  many  sucking  insects,  especially  scales,   aphids   •

3 tablespoons  (1/3  cup)  cooking  oil  in  4  litres   water  

½ teaspoon  detergent  soap  

Shake well  and  use  

MILK: active  against  powdery  mildew  fungi   Use  milk,  diluted  to  10%  (1  part  milk,  9  parts   water);   Add  soap  if  milk  does  not  spread  over  leaf   surface.  

• •

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Melanesian Coconut  Beetle  

Extension Fact  Sheet  

57

Common  names:  Melanesian  rhinoceros  beetle,  Coconut  rhinoceros  beetle,  Scapanes   Scientific  name:  Scapanes  australis.  Different  sub-­‐species  (S.  australis  australis  and  S.  australis   grossepunctatus)  exist  in  Papua  New  Guinea,  but  the  situation  in  Solomon  Islands  has  not  been   studied.   Hosts:  The  main  hosts  are  coconut,  oil  palm  and  betel  nut,  but  the  beetle  is  also  found  on   banana,  sugarcane  and  wild  palms.      

Damage The  adults  bore  into  crowns  of  coconut,  oil  palm  and  other  palm  species,  as  well  as   pseudostems  of  bananas.  Damage  to  coconuts  is  considerable,  especially  up  to  5  years’  old.   The  emerging  fronds  show  V-­‐shaped  cuts,  twisting,  spiraling  and  truncated  leaflets.  If  the   growing  point  is  damaged,  the  palms  die.  The  damage  allows  entry  of  other  organisms:   termites  and,  especially,  Rhynchophorus,  the  Black  palm  weevil.     Damage  can  be  severe  when  coconuts  are  planted  in  land  cleared  from  forest,  where  the   rotting  logs  provide  breeding  sites.  All  the  palms  may  be  damaged  within  5  years,  discouraging   farmers  from  planting  or  replanting  the  crop.  However,  as  the  logs  rot  away  so  the  attack   decreases.    

Biology and  Life  Cycle   The  egg  is  creamy-­‐white,  about  5  mm  long  and  3  mm  diameter,  and  is  laid  singly  in  soil  near   rotting  logs  or  other  decaying  matter  that  is  food  for  the  larvae.  In  Papua  New  Guinea,   breeding  sites  occur  in  cocoa  and  coconut  plantations  associated  with  rotting  stumps  of  shade   trees  (Gliricidia  sepium).  Breeding  sites  have  also  been  found  in  old  nests  of  magapodes,  when   these  were  near  breadfruit  trees.     Eggs  hatch  after  about  30  days  producing  C-­‐shaped  larvae  (photo,  left),  with  heads  of  reddish   brown  to  brown.  As  the  larvae  grow,  they  moult  twice,  reaching  10  cm  in  length  and  2  cm   thick,  before  pupating  at  9  months  or  more.  Adults  are  black,  4-­‐6  cm  long,  and  are  strong  fliers.   Males  are  horned  (photo,  right),  while  females  have  small  double  horns  on  their  heads.  Adults   live  for  about  4  months.  Males  and  females  have  been  seen  in  the  same  tunnel  in  the  crown  of   a  coconut,  but  it  is  the  male  alone  that  is  seen  most  commonly.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  the  larvae  beneath  rotting  logs.  However,  they  need  to  be  bred  to  adults,  as  they  are   similar  to  other  beetles  in  the  scarab  family.  Keep  them  in  a  sterilised  cowdung  and  sawdust   mixture.  Look  for  the  horns  on  the  adult  males  beetles,  they  are  characteristic,  whereas   females  may  be  more  difficult  to  recognize.     Oryctes  is  not  present  in  Solomon  Islands,  so  confusion  with  that  insect  is  unlikely;  also,   Oryctes  attacks  much  older  palms.     In  the  field,  inspect  the  crown  of  the  palms,  looking  for  V-­‐shaped  cuts  in  the  leaves,  distorted   fronds  and  fibre  pushed  from  the  tunnels  into  the  crown.  Follow  the  tunnel  to  find  the  beetle.  

Management Control  of  Scapanes  is  difficult  as  the  number  of  adult  beetles  is  relatively  low  per  hectare,   albeit  they  can  cause  substantial  damage.  

NATURAL ENEMIES   A  pheromone  has  been  isolated  and  used  in  mass  trapping  trials  in  Papua  New  Guinea.  It  is   said  to  be  easy  to  make  and  is  cheap.  It  attracts  both  males  and  females.  It  is  still  to  be  put  to   use  in  smallholder  and  estate  plantations.    

RESISTANT VARIETIES   •

None known  in  Solomon  Islands,  but  fast-­‐growing  varieties  are  more  likely  to  outgrow  the   damage  caused  by  the  beetles.  In  Papua  New  Guinea,  fewer  coconuts  of  Gazelle  Tall  died   from  attack  compared  to  Rennell  Tall  or  Malayan  Dwarf.  

CULTURAL CONTROL   • •

Remove or  burn  breeding  sites,  logs  in  particular  (a  difficult  practice  for  small  holders   when  clearing  sites  from  forest);     Plant  Pueraria  phaseolodes  or  other  legume  species  as  soon  as  the  trees  have  been  felled   to  cover  the  logs  and  stumps  in  order  to  interrupt  egg  laying.  

CHEMICAL CONTROL   Chemical  control  of  this  pest  is  very  difficult  and  not  recommended  under  small-­‐scale   production  systems.  If  it  is  required:   •

Put granules  of  insecticide  in  the  axils  of  the  fronds.  Lindane  and  BHC  have  been  used  in   the  past,  but  the  production  and  use  of  these  chemicals  is  banned  by  international   agreement.  Furadan  granules  have  been  used  as  an  alternative.  

 

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Plant-­‐eating Ladybeetles  

Extension Fact  Sheet  

58

Common  name:  Eggplant  ladybird  beetle;  26-­‐spotted  ladybird   Scientific  name:    Epilachna  (Henosepilachna)  vigintisexpunctata.  Note,  the  number  of  spots  is   variable  and  cannot  be  used  to  identify  the  ladybird  beetles.   Hosts:  Eggplant.  It  is  likely  that  it  feeds  on  other  members  of  Solanaceae,  including  tomato  and   weeds.  Another  species,  E.  signatipennis,  has  been  identified  from  long  beans,  and  most  likely   can  be  found  on  other  legumes.  Other  species  of  Epilachna  occur  in  Solomon  Islands  on  these   and  other  crops,  including  cucurbits  and  maize.  All  have  similar  life  cycles.    

Damage  

The adults  and  larvae  (photo,  left)  eat  the  surface  of  the  leaves  (photo,  right);  the  larvae  graze   the  under  surface,  leaving  the  upper  surface  intact;  adults  feed  on  both  sides  of  the  leaf,   sometimes  making  holes  as  they  chew.  Seedlings  may  be  killed  by  the  attack,  and  growth  and   yield  of  more  mature  plants  reduced.    

Biology and  Life  Cycle   The  adults  are  like  typical  ladybeetles  with  wing  cases  of  dull  orange  and  black  spots;  however,   close  inspection  shows  that  the  upper  surface  is  covered  in  short  downy  hairs.  This   distinguishes  plant-­‐feeding  ladybeetles  from  their  beneficial  bug-­‐feeding  relatives.  The  oval   yellow  eggs  (1  mm  by  0.4  mm)  are  laid  upright  in  batches  of  10-­‐20  on  the  underside  of  a  leaf.   They  hatch  in  about  4  days.  The  pale  yellow  larvae  have  long,  dark-­‐tipped  branched  spines  on   their  backs;  they  grow  to  6  mm  through  three  moults  in  the  next  18  days,  before  attaching   themselves  to  the  undersides  of  the  leaves  and  developing  into  pupae.  This  stage  lasts  another   4  days.         The  adults  fall  to  the  ground  when  disturbed,  pretending  to  be  dead.  They  also  produce  a   yellow  fluid  that  wards  off  predators.      

Detection and  Inspection   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Look  for  the  distinctive  grazing  on  one  side  of  the  leaf,  often  leaving  the  surface  of  the  other   side  intact.  Look  for  the  larvae,  mostly  on  the  underside,  and  the  adults  on  the  top  of  leaves,   but  always  check  that  the  beetles  are  leaf  eating,  i.e.,  they  are  feeding  on  the  leaf,  and  are  not   beneficial  species  feeding,  for  instance,  on  aphids  (green  flies).  

Management NATURAL  ENEMIES   There  have  been  no  studies  of  the  natural  enemies  of  Epilachna  species  in  Solomon  Islands.   Elsewhere,  species  of  a  parasitic  wasp  (Pediobius)  have  been  introduced,  achieving  successful   control  of  Epilachna.  There  are  different  species  of  the  beetles,  so  identification  needs  to  be   done  carefully.  Also,  care  should  be  taken  to  ensure  that  any  Pediobius  introduced  are  specific   to  the  pest  species,  and  not  likely  to  attack  beneficial  members  of  the  family.  

RESISTANT VARIETIES   •

None known  in  Solomon  Islands,  although  comparative  resistance  of  some  varieties  of   eggplant  is  known  in  India.  

CULTURAL CONTROL   • •

Handpick the  larvae,  and  perhaps  the  adults.  If  attempted,  it  should  be  done  when  the   beetles  are  first  seen  in  the  crop;   Remove  weeds  in  the  Solanaceae  family  from  around  the  crop.  However,  it  has  been   suggested  these  might  act  as  trap  crops,  so  some  experimentation  is  needed.    

CHEMICAL CONTROL   •

Use contact  insecticides,  such  as  malathion,  or  synthetic  pyrethroids,  such  as  lambda   cyhalothrin  or  permethrin.  The  choice  of  chemical  is  important:  use  those  that  are  least   persistent  in  the  environment,  and  have  low  toxicity  against  bees.     A  variety  of  Derris,  brought  many  years  ago  from  Papua  New  Guinea,  is  effective  as  a   spray.  It  contains  rotenone,  an  insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for   evaluation  by  growers.  Contact  those  organisations  for  plants  to  test.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Coconut Hispine  Beetle  

Extension Fact  Sheet  

59

Common  names:  Coconut  hispine  beetle,  Coconut  leaf  hispa   Scientific  name:    Brontispa  longissima.   Hosts:  Coconuts  are  the  most  important  crop  attacked,  but  the  beetle  also  infests  betel  nut,   sago  palm,  oil  palm,  and  a  number  of  ornamental  and  wild  palms.      

Damage Palms  of  all  ages  are  attacked,  but  the  damage  done  to  seedlings  in  nurseries  and  young  palms   after  planting  out  is  often  severe.  The  adults  (photo,  left)  and  larvae  graze  the  leaflets  of  the   unopened  spear  leaf,  forming  narrow  red-­‐brown  streaks  parallel  to  the  midrib.  As  the  leaf   unfolds,  these  streaks  enlarge,  forming  irregular  greyish  blotches  (photo,  right);  when  severe,   this  gives  the  palm  a  scorched  appearance  (photo,  centre).       Severe  attacks  may  kill  the  palm,  and  those  that  survive  are  more  susceptible  to  drought  and   disease.  Yield  of  bearing  palms  is  reduced  considerably.  

Biology and  Life  Cycle   The  entire  life  cycle  of  the  beetles  takes  place  in  the  unopened  spear  leaf.  Eggs  are  laid  in   grooves  chewed  into  the  leaflets  and  covered  by  excreta.  The  eggs  hatch  after  4-­‐5  days,  and   the  larvae  pass  through  several  moults  during  the  next  4  weeks  before  they  pupate.  Six-­‐days’   later  the  adults  emerge.  They  are  8-­‐10  mm  long  and  2  mm  wide  (photo,  above  left),  and  live   for  about  7  months.  The  females  lay  100  eggs  or  more.    

Detection and  Inspection   Look  for  the  narrow  brown  streaks  on  the  leaflets,  and  red  and  black  beetles  between  them.   Look  for  fronds  with  ragged  leaflets,  with  those  still  green  bearing  large  dry  dead  blotches   parallel  to  the  length  of  the  leaflets.         AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management NATURAL  ENEMIES   Brontispa  is  mostly  under  control  by  its  natural  enemies.  Tetrastichuss  brontispae  was   introduced  successfully  into  the  Russell  Islands  in  the  1960s,  making  the  spraying  of  young   palms  unnecessary.  The  wasp  lays  its  eggs  in  the  late  larval  and  pupal  stages.  Another   parasitoid,  Asecodes  hispinarum,  attacks  the  4th  stage  larvae,  and  following  its  introduction   into  Asia  in  2003,  has  been  responsible  for  controlling  serious  outbreaks  of  Brontispa.     Earwigs  (Chelisoches  morio)  are  reported  to  feed  on  the  larvae  of  Brontispa  in  other  countries,   and  the  fungus,  Metarhizium  anisopliae,  also  causes  high  mortality.  Whether  the  organisms   are  present  and  provide  control  in  Solomon  Islands  is  not  known.    

RESISTANT VARIETIES   •

In Solomon  Islands,  there  is  evidence  that  the  Local  Tall  and  Rennell  varieties  are  more   resistant  than  Federated  Malay  States  and  Malayan  Dwarf.  The  hybrid  between  Rennell   Tall  and  Malayan  Dwarf  is  susceptible.    

CHEMICAL CONTROL   Occasionally,  insecticides  are  needed  in  the  nursery  and  on  young  palms  after  planting  out,   especially  where  susceptible  varieties  of  coconuts  are  planted  in  areas  that  have  dry  seasons,   e.g.,  the  Guadalcanal  Plains.       • Use  contact  insecticides,  such  as  malathion,  or  synthetic  pyrethroids,  such  as  lambda   cyhalothrin  or  permethrin.  The  choice  of  chemical  is  important:  use  those  that  are  least   persistent  in  the  environment,  and  have  low  toxicity  against  bees.     • Derris  (rotenone)  may  be  effective  against  the  beetle.  A  local  variety  of  Derris,  originally   from  Papua  New  Guinea,  with  a  high  concentration  of  rotenone,  is  being  multiplied  by   MAL  and  the  Kastom  Gaden  Association.  [See  these  organisations  for  cuttings.]    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Coconut Leafminer  

Extension Fact  Sheet  

60

Common  names:  Coconut  leafminer,  Coconut  leaf  hispid   Scientific  name:    Promecotheca  spp.  Several  species  are  recorded  from  Solomon  Islands.  (The   photos  are  from  an  outbreak  in  Vanuatu1).   Hosts:  Coconuts  are  the  most  important  crop  attacked,  but  the  beetle  also  infests  betel  nut,   sago  palm,  and  a  number  of  ornamental  and  wild  palms.  It  is  not  a  pest  of  oil  palm.  

Damage   The  adults  feed  on  the  lower  surface  of  the  furthest  third  to  a  half  of  the  leaflets,  leaving   narrow  furrows  (photo,  centre);  the  larvae  mine  the  leaflets,  leaving  large  areas  of  damage   (photo,  left).  The  youngest  three  to  fours  leaves  are  first  attacked.  In  general,  the  beetles  are   more  damaging  to  mature  palms,  25  m  or  more  in  height,  although  seedlings  may  become   infested.  Occasionally,  the  green  tissue  on  all  leaflets  is  destroyed  and,  consequently,  young   nuts  fall,  yield  is  severely  reduced,  flower  production  ceases,  and  palms  may  die.  Entire   coconut  plantations  turn  brown  (photo,  right).  Severe  outbreaks  set  back  nut  production  for  at   least  2  years.  Such  events  are  rare,  however.     Outbreaks  appear  to  be  cyclical,  every  10-­‐15  years  or  so,  and  may  be  brought  about  by   droughts.  If  this  is  the  case,  more  frequent  outbreaks  of  Promecotheca  can  be  expected  in   future,  as  El  Nino  events  intensify  due  to  climate  change.  

Biology and  Life  Cycle   Eggs,  about  1.5  mm  long,  are  laid  on  the  underside  of  the  leaflets  of  younger  fronds,  either   singly  or  2-­‐3  together  –  depending  on  the  species  –  and  covered  with  digested  leaf  fragments   cemented  together.  The  larvae  hatch  after  2-­‐3  weeks  (depending  on  the  temperature),  and   penetrate  the  leaflets  and  form  a  mine  parallel  to  the  midrib.  More  than  one  larva  can  be   1

Information on  the  insect  is  taken  from  FW  Howard  et  al.  (2001)  Insects  on  palms.  CABI  Publishing,  UK.  The  photos  were  kindly   provided  by  Jean-­‐Pierre  Labouisse,  CIRAD,  Montpellier,  France.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   present  in  each  mine.  The  larvae  moult  2-­‐3  times,  and  during  this  time  the  mine  enlarges  from   1  to  5  mm  wide.  The  mines  are  80  to  400  mm  long,  depending  on  the  species  and  the  number   of  larvae  in  the  mine.  The  larval  stage  is  up  to  40  days;  it  also  varies  depending  on  the  species.   The  pupal  stage  occurs  in  the  mine,  and  lasts  about  12  days.       After  emergence,  males  and  females  fly  to  younger  leaflets  on  the  same  palm  or  to  a  young   leaf  of  a  palm  nearby,  grouping  together  on  the  underside  of  the  fronds.  The  beetles  are  not   strong  fliers;  but  they  prefer  the  tallest  trees,  especially  ones  in  sunlight.  The  adult  is  about  1   cm  long.  Colours  vary,  but  they  are  often  colourful.  One  species  from  the  Santa  Cruz  group  has   a  black  head  with  wings  of  orange  nearest  the  front  and  brilliant  bluish  purple  to  metallic   green  behind.  About  2  weeks  after  emergence,  they  mate.  The  adults  live  for  about  4  weeks.    

Detection and  Inspection   On  mature  coconuts,  look  for  signs  of  adult  feeding  on  the  lower  parts  of  young  fronds;  the   adults  eat  the  lower  epidermis  making  long  grooves  into  the  leaf,  parallel  to  the  veins.  Hold   the  leaflets  to  the  light  to  see  these  grooves  as  fine  white  lines.  The  leaflets  become  brown,   then  grey,  and  almost  white,  and  the  tips  shrivel  and  curl  under.  Look  for  the  beetles  during   the  day,  7-­‐9  mm  long,  and  brightly  coloured.  Look  for  signs  of  the  larvae  in  the  upper  part  of   the  leaflet.  The  older  larvae  should  be  visible  at  the  end  of  the  mines,  which  are  straight,   parallel,  and  similar  in  shape,  when  the  leaflet  is  held  to  the  light.    

Management NATURAL  ENEMIES   Promecotheca  is  under  natural  control  in  Solomon  Islands,  as  it  is  elsewhere,  and  only  rarely   do  outbreaks  occur.  Several  parasitoids,  mostly  minute  wasps,  that  parasitise  eggs  and  larvae,   and  parasitic  fungi,  have  been  reported  from  other  countries.  The  ant,  Oecophylla  smaragdina   was  found  to  be  of  the  greatest  importance  in  controlling  one  species  in  Papua  New  Guinea,   which  also  occurs  in  Solomon  Islands.  And  the  ants,  Pheidole  and  Technomyrmex,  are  also   known  to  attack  egg  masses.  

CULTURAL CONTROL   • •

Hand pick  Promecotheca  eggs  and  adults  on  seedlings  in  nurseries,  and  young  palms  in  the   field;   Prune  and  burn  infested  fronds.  Burning  of  infested  leaflets  while  still  on  the  palm  is   reported.  Whether  these  are  good  practices  is  unclear,  as  they  will  also  destroy  any   parasitoids  present.  

CHEMICAL CONTROL   •

The use  of  insecticides  to  control  this  insect  is  not  recommended.  Not  only  is  it  difficult  to   spray  mature  coconuts,  and  probably  uneconomic  to  do  so,  but  it  will  harm  the  parasitoids   and  delay  the  re-­‐establishment  of  natural  control.  If  sprays  are  needed  in  the  nursery,  use   malathion  or  synthetic  pyrethroids,  such  as  lambda  cyhalothrin  or  permethrin.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cocoa Weevil  Borer  

Extension Fact  Sheet  

61

Common  name:  Cocoa  weevil  borer   Scientific  name:    Pantorhytes  species.  P.  biplagiatus  is  a  serious  pest  of  cocoa  in  Solomon   Islands1.   Hosts:  Cocoa  and  several  commercial  forest  trees,  e.g.,  Eucalyptus  and  Terminalia.  

Damage  

The larvae  do  the  damage.  They  bore  into  the  sapwood  of  trunks  and  branches,  making   tunnels  1-­‐3  cm  deep  (photo,  centre).  Often  the  tunnels  are  made  at  or  near  the  jorquette,  the   junction  of  branches  and  trunk.  Damage  at  the  jorquette  has  the  potential  to  do  considerable   harm.  The  overall  effect  of  the  damage  is  to  weaken  the  trees,  causing  tip  dieback,  death  of   branches  due  to  ring  barking,  and  even  death  of  the  tree  if  splits  occur  at  the  jorquette.   Consequently,  pod  yields  may  be  reduced  considerably.     The  wounds  made  by  larvae  may  allow  entry  of  the  bark  canker  Water  mould,  Phytophthora   palmivora  (see  Fact  Sheet  no.  6),  and  also  termites.  

Biology and  Life  Cycle   The  white,  oval  eggs,  about  2  mm  long,  are  laid  singly  in  crevices  in  the  trunk  and  main   branches,  particularly  near  the  jorquette.  They  hatch  after  2-­‐3  weeks.  The  larvae  bore  into  the   wood,  feeding  for  3-­‐9  months  through  nine  instars,  and  then  pupate  beneath  the  bark  for   about  2  weeks.       The  adults  are  black  and  red  (photo,  left),  wingless  weevils  about  1.5  cm  long.  They  feed  for  4-­‐ 6  weeks  before  mating;  afterwards,  the  female  lays  about  two  eggs  a  day  throughout  a  life  of   1-­‐2  years.  Adults  feed  on  the  bark  of  young  cocoa  shoots,  flowers  and,  occasionally,  pods,  but   the  damage  is  not  sufficient  to  affect  pod  production.     1

The photos of the adult and larvae are from The World’s Worst Cocoa Problems: http://www.dropdata.org/cocoa/cocoa_prob.htm. The photo of the crazy ant is taken from the Japanese Ant Image Database: http://ant.edb.miyakyo-u.ac.jp/E/P/PCD1050/43.html.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  holes  in  the  trunk  and  branches,  particularly  at  the  jorquette;  look  for  the  jelly-­‐like   substance  that  exudes  from  the  holes  where  the  larvae  feed.  Look  for  the  adult  beetles,  that   have  a  red  abdomen  with  white  spots,  and  are  relatively  slow  moving,  sufficient  to  be   handpicked.  

Management NATURAL  ENEMIES   Biocontrol  of  Pantorhytes  is  possible  using  the  crazy  ant,  Anoplolepis  gracilipes,  or  Oecophylla   smaragdina.  The  ants  make  colonies  in  soursop  trees,  so  these  should  be  planted  between   cocoa  trees  to  encourage  the  ants  to  colonise  them.  The  Little  fire  ant,  Wasmannia   auropunctata,  too,  may  be  antagonistic  to  Pantorytes.     The  yellow-­‐brown  crazy  ant  has  long  legs  and  antennae  (photo,  right).  Its  total  length  is  about   4  mm.  It  kills  its  prey  by  spraying  formic  acid.  Wasmannia  is  smaller.  

CULTURAL CONTROL   • •

• •

Hand pick  Pantorhytes  adults  (they  do  not  have  wings)  during  the  middle  of  the  day  when   they  come  down  from  the  canopy  to  find  cooler  places;   In  severely  infested  plantations,  find  the  larvae  by  looking  for  frass  pushed  out  of  the   entrance  of  the  larval  tunnel  and/or  the  jelly-­‐like  substance.  Remove  the  frass  with  a  stiff   brush  and  apply  a  solution  of  Dichlorvos,  white  oil,  Ridomil  and  water  with  a  small  2  cm   brush  onto  the  bark  around  the  entrance  hole.  (Ridomil  is  added  to  control  Phytophthora).   Repeat  every  2  weeks;   For  smallholders,  find  the  tunnels  made  by  the  larvae,  and  kill  them  with  a  piece  of  wire;   If  possible,  plant  cocoa  beneath  coconuts  as  Pantorhytes  numbers  are  less  than  under   forest  trees,  Leucaena  or  Gliricidia;  possibly,  the  lower  numbers  are  associated  with  higher   ant  populations  under  coconuts.  

CHEMICAL CONTROL   The  use  of  insecticides  –  other  than  as  ‘paints’  to  kill  larvae  -­‐  is  not  recommended.  The   difficulty  of  bringing  the  chemical  into  contact  with  the  larvae  inside  their  tunnels,  and  the  low   populations  of  beetles  makes  their  use  uneconomical.     Clean  the  entrance  of  tunnels  and  apply  Dichlorvos,  white  oil,  Ridomil  and  water.  Applying   insecticides  in  any  other  way  has  little  or  no  effect.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Coconut Spathe  Bug  

Extension Fact  Sheet  

62

Common name:  Coconut  spathe  bug   Scientific  name:    Axiagastus  cambelli.  [Note  that  the  photo,  right,  is  provided  for  reference   only;  it  was  not  taken  in  Solomon  Islands,  and  may  not  be  a  pest  of  coconuts1.]   Hosts:  Coconut  and  betel  nut.    

Damage  

The damage  done  by  the  bug  is  uncertain.  There  is  some  loss  of  young  nuts  when  populations   are  high,  and  outbreaks  in  Santa  Cruz  (Nendo  Island)  have  occurred  on  coconuts  that  have   produced  dry,  banana-­‐shaped  nuts.  However,  it  has  not  been  proven  that  Axiagastus  is  the   cause  of  the  condition:  it  is  still  only  an  association.  Nutritional  deficiencies  have  also  been   suggested  as  well  as  poor  fertilisation  of  the  flowers.     Both  adults  and  nymphs  have  long  piercing  mouthparts  and  they  can  insert  these  into  young   coconuts  to  suck  sap.  It  is  this  feeding  that  is  presumed  to  cause  the  young  nuts  to  fall,  and   those  that  remain  become  long  and  thin,  without  ‘meat’  and  ‘milk’.  Whether  or  not  the  bug   injects  a  poison  as  it  feeds  is  not  known,  but  it  is  thought  unlikely.  

Biology and  Life  Cycle   The  barrel-­‐shaped,  white  eggs  are  laid  in  clusters  on  the  flowers,  on  the  fibrous  sheath  at  the   base  of  the  fronds  and,  more  rarely,  on  the  leaflets.  Eggs  hatch  in  6-­‐8  days,  and  the  nymphs,   which  are  white  at  first  then  orange  with  black  markings,  moult  four  times  before  they  become   adults.  The  time  from  egg  to  adult  is  about  45  days.       The  adults  are  dark  brown  with  yellow  marks,  about  15  mm  long.  They  give  out  a  strong   unpleasant  smell  when  held  or  disturbed.   1

The photo  of  the  bug  was  taken  from  the  National  Taiwan  University  Insect  Museum  Digital  Archives  Project.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   The  bugs  occur  in  large  numbers  on  the  newly  opened  spadices,  feeding  on  male  and  female   flowers.  The  smell  when  disturbed  is  also  a  characteristic  of  the  bugs.  

Management NATURAL  ENEMIES   In  Papua  New  Guinea,  surveys  have  found  egg,  nymph  and  adult  parasitoids  (e.g.,  the  wasps,   Trissolcus  painei  and  Anastatus  sp.,  as  well  as  the  fly,  Pentatomophaga  bicincta),  and  it  is  likely   that  there  are  related  species  in  Solomon  Islands.  Oecophylla  smaragdina  (Weaver  ant,  Green   ant,  Green  tree  ant)  is  said  to  reduce  populations  of  this  pest  as  it  does  for  those  of  Amblypelta   (see  Fact  Sheet  no.  19).  Thus,  planting  soursop  and  other  fruit  trees  that  host  colonies  of   Oecophylla  within  coconut  plantations,  and  then  helping  the  ant  to  establish  on  these  trees,  by   placing  ‘nests’  in  the  canopy,  may  help  to  reduce  Axiagastus  numbers.     It  is  likely  that  the  recently  introduced  fire  ant,  Wasmannia  auropunctata,  will  also  provide   control,  although  this  is  only  speculation.  

CHEMICAL CONTROL   The  use  of  insecticides  is  not  recommended.  The  bug  is  usually  under  control  naturally,  and   outbreaks  only  occur  occasionally.  Insecticides  would  only  increase  the  time  before  the   balance  between  the  pest  and  its  parasitoids  was  re-­‐established.  Additionally,  there  is  the   difficulty  of  spraying  mature  palms,  making  the  application  of  insecticides  difficult  as  well  as   uneconomical.    

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cucurbit Powdery  Mildew  

Extension Fact  Sheet  

63

Common  name:  Cucurbit  powdery  mildew   Scientific  name:  In  Solomon  Islands,  and  other  Pacific  Island  countries,  only  the  asexual  state   has  been  found;  this  is  known  as  Oidium.  The  Oidium  or  asexual  state  of  many  different   powdery  mildews  looks  the  same.  However,  from  research  elsewhere,  it  is  known  that   Cucurbit  powdery  mildew  belongs  to  one  of  two  sexual  states:  Sphaerotheca  fuliginea  or   Erysiphe  cichoracearum.   Hosts:  Cucurbits  are  hots;  common  cucurbits  are  cucumber,  melon,  pumpkin,  squash  and   zucchini.  Some  legumes  and  ornamentals  are  also  susceptible  to  infection.    

Damage The  disease  can  be  a  major  problem.  Powdery  mildews  seldom  kill  their  hosts,  but  use  their   nutrients,  reduce  photosynthesis,  impair  growth  and  reduce  yields.  The  size  and  number  of   fruits  is  reduced,  or  plants  die  early.  Early  death  of  the  leaves  lowers  market  quality  because   fruit  become  sunburned,  ripen  prematurely,  do  not  store  well,  or  have  poor  flavour.  In   addition,  plants  with  powdery  mildew  are  more  likely  to  become  infected  with  other  diseases,   Gummy  stem  blight  in  particular  (see  Fact  Sheet  No.  7).    

Biology and  Life  Cycle   The  fungus  is  unusual  in  that  it  cannot  survive  in  the  absence  of  a  living  host.  It  is  also  unusual   in  that  it  grows  over  the  leaf  surface,  and  that  is  the  reason  why  the  leaf  appears  white  (photo,   right:  cucumber  &  left:  pumpkin).  In  order  to  feed,  the  fungus  sends  special  cells  into  the  leaf   and  these  extract  the  food  it  needs  for  growth.  Spores,  called  conidia,  are  produced  in  chains   on  single  strands  of  its  cottony  growth  that  stand  erect  from  the  leaf  surface.  The  spores  are   spread  in  the  wind;  they  need  high  humidity  to  germinate,  but  not  water.  The  time  between   infection  and  symptoms  is  short,  3-­‐5  days  (depending  on  temperatures).  Spread  is  fast,   especially  if  plants  are  close  together,  humidity  is  high,  and  there  is  no  rain.    

Detection and  Inspection   Look  for  white,  powdery  fungal  spots  on  upper  leaf  surfaces,  petioles  and  stems.  Look  for  the   fungus  on  the  shaded  older  leaves.  Infection  on  the  under  surface  is  often  not  as  clear  because   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with   support   from   IPPSI:   Improved   Plant   Protection   in   Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   of  the  lighter  colour  of  the  leaf;  although  on  the  pumpkin  (photo,  left)  it  is  exceptionally  clear.   The  fungal  spots  expand  and  multiply  rapidly,  so  look  for  leaves  that  gradually  turn  yellow,   then  brown,  dry  out  and  die.  

Management CULTURAL  CONTROL   Cultural  control  measures  are  important  to  reduce  the  disease:     • Plant  in  sunny  places,  and,  if  possible,  choose  areas  with  good  air  circulation;   • Do  not  plant  successive  crops  of  cucurbits  in  the  same  gardens;   • Do  not  plant  new  crops  next  to  those  that  have  the  disease;  otherwise  spread  of  the   disease  to  the  new  crop  will  be  rapid  and  devastating;   • Remove  weeds  from  within  and  around  the  crop:  many  weeds  are  hosts  of  powdery   mildew,  so  make  sure  they  are  controlled.  

RESISTANT VARIETIES   •

There are  varieties  of  cucumber  and  melon  with  resistance.  Check  company  descriptions  of   varieties  of  pumpkin  and  squash,  and  choose  those  with  resistance.  

CHEMICAL CONTROL   If  fungicides  are  used,  inspect  the  crop  regularly  to  detect  when  infections  first  occur.  Start   spraying  immediately,  and  spray  routinely,  every  7-­‐10  days  depending  on  the  severity  of  the   disease.  Do  the  following:   • If  following  an  organic  regime,  use  products  containing  horticultural  oil,  potassium   bicarbonate  or  wettable  sulphur.  The  last  two  are  best  applied  before  disease  symptoms   appear.  Oils  are  eradicants,  meaning  they  can  cure  plants  that  are  already  infected,  but   also  have  some  protectant  activity;   • Wettable  sulphur  has  been  used  for  many  years  for  powdery  mildew  control.  Apply  in  the   early  morning  or  evening,  at  the  coolest  times  of  the  day.  Never  spray  sulphur  within  2   weeks  of  the  last  application  of  an  oil  spray.  Also,  sulphur  can  burn  the  leaves,  so  read  the   label  carefully  before  applying;   • Where  the  number  of  plants  is  small,  use  milk:  normal  strength  diluted  1  part  in  10  parts  of   water;   • For  large  commercial  plantings,  apply  wettable  sulphur  products,  chlorothalonil  (also   useful  for  Gummy  stem  blight  control)  or  check  availability  of  other  products  (e.g.,   triazoles),  and  seek  advice  from  MAL  extension  officers.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with   support   from   IPPSI:   Improved   Plant   Protection   in   Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Brown Plant  Hopper  

Extension Fact  Sheet  

64

Common  name:  Brown  planthopper   Scientific  name:  Nilaparvata  lugens.   Hosts:  Rice  and  wild  grasses.    

Damage   Both  adults  (photo,  centre)  and  nymphs  (photo,  left)  do  the  damage.  They  have  piercing   mouthparts  that  they  insert  into  the  leaf  blades  and  leaf  sheaths  (‘stems’)  of  rice  plants  to  suck   the  sap.  Also,  egg  laying  blocks  the  water  and  food  channels  inside  the  plant.       Symptoms  depend  on  variety,  number  of  planthoppers,  and  plant  age:  tiller  and  panicle   number,  and  plant  height,  are  reduced;  grains  are  unfilled;  injury  from  feeding  and  egg  laying   allows  entry  of  fungi  and  bacteria,  and  sooty  mould  fungi  blacken  stems.  Severe  infestations   cause  plants  in  the  ‘milk’  or  ‘dough’  stages  to  gradually  yellow  from  the  tip,  brown,  dry  out  and   collapse  -­‐  a  wilt,  known  as  ‘hopperburn’;  photo,  above  right.  The  most  susceptible  time  is  from   tillering  to  flowering.  Hopperburn  is  more  common  in  paddy  than  dryland  rice.  

Biology and  Life  Cycle   Eggs  are  laid  in  the  midrib  of  the  leaf  blades,  4-­‐10  in  an  egg  mass;  they  are  cylindrical,  slightly   curved,  1  mm  long,  white  at  first,  darker  when  about  to  hatch,  with  two  spots  -­‐  the  eyes  of  the   nymph.  The  eggs  hatch  in  4-­‐8  days.  Nymphs  are  creamy  white  with  a  pale  brown  tinge,  later   becoming  dark  brown.  There  are  four  to  five  moults.  The  final  nymphs  are  nearly  3  mm  long,   with  a  line  from  the  top  of  the  head  to  the  middle  part  of  the  body  where  it  is  widest.  Adults   are  brownish  black  with  a  yellowish-­‐brown  body.  There  are  two  forms,  long  winged  and  short   winged.       Infestations  start  with  the  arrival  of  the  winged  form,  which  lay  eggs  and  produce  the  wingless   form.  Winged  form  develops  when  numbers  are  high;  females  are  about  4  mm  and  males  4.5   mm;  wingless  forms  are  smaller.  After  harvest,  the  planthoppers  migrate  to  grasses,  or  spread   to  new  crops  of  rice.  Brown  planthoppers  live  for  up  to  20  days.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  at  the  base  of  the  plants,  where  it  is  shady  and  humidity  is  high,  for  the  nymphs  and   winged  and  wingless  adults.  Look  for  the  sooty  mould  fungi  that  often  accompany  large   numbers  of  the  insects.  More  than  3-­‐5  insects  per  tiller  is  considered  high,  needing  more   intensive  observation  and  possibly  insecticide  treatment.  

Management Over  use  of  insecticides  is  the  main  cause  of  outbreaks  of  Brown  planthopper.  IPM  programs   stress  the  need  to  main  biological  control  –  natural  enemies  –  and  also  include  resistant   varieties.  The  routine  use  of  insecticides  should  be  avoided.  

NATURAL ENEMIES   There  are  a  number  of  natural  predators  of  the  Brown  planthopper:  spiders  eat  the  nymphs   and  adults,  as  do  coccinellid  beetles,  dragonflies  and  damselflies.  There  are  two  species  of   mired  egg-­‐sucking  bugs  in  Solomon  Islands  -­‐  Cyrtorhinus  chinensis  and  C  lividipennis  -­‐  and   there  are  likely  to  be  wasp  parasitoids  that  attack  eggs,  as  well  as  fungal  pathogens  and  mites.    

CULTURAL CONTROL   • • • • •

Drain the  paddies  for  3-­‐4  days  during  the  early  stage  of  infestation;   Apply  split  applications  (three  times)  of  nitrogen  fertilizer;   Avoid  staggered  planting,  preventing  planthoppers  moving  from  older  to  younger  crops;     Remove  volunteer  plants;   Rotate  rice  with  other  crops.  

RESISTANT VARIETIES   Egg  laying  and  survival  of  nymphs  differs  between  rice  varieties.  Many  varieties  have  been   bred  for  resistance  to  Brown  planthopper;  unfortunately,  there  are  many  cases  when  changes   in  the  insect  have  overcome  the  resistance.  

CHEMICAL CONTROL   Insecticides  should  only  be  used  when  plantshopper  populations  are  likely  to  reach  an   economic  injury  level;  otherwise  natural  enemies  will  be  destroyed  and  planthopper   populations  will  return  greater  than  before.  The  systemic  insecticide,  Orthene  (acephate),  has   been  used  for  many  years  against  the  Brown  planthopper  in  Solomon  Islands.  Check  for   current  recommendations  from  MAL  Research/Extension  officers,  as  well  as  the  timing  and   method  of  application.    

 

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Coconut Flat  Moth  

Extension Fact  Sheet  

65

Common  name:  Coconut  flat  moth   Scientific  name:  Agonoxena  sp.  The  main  pest  species  of  other  Pacific  Island  countries  is  A.   argula  (photo,  centre1);  but  this  is  not  present  in  Solomon  Islands.  A.  pyrogramma  is  present.  It   is  native  to  Solomon  Islands.     Hosts:  Coconuts  and  other  palms.    

Damage The  larvae  of  the  flat  moth  (photo,  centre)  do  the  damage  by  eating  mainly  the  lower  surface   of  the  leaflets.  They  make  lines  1-­‐2  mm  wide  and  2-­‐3  cm  long  near  the  mid-­‐rib;  the  damaged   lines  are  light  grey  (photos,  left  &  right).  There  is  no  evidence  that  coconut  production  is   affected  by  the  damage,  although  the  leaves  can  look  ragged.  However,  it  is  possible  that  the   growth  of  seedlings  may  be  slowed  by  the  attack.     A.  pyrogramma  does  not  do  nearly  as  much  damage  as  A.  arguala,  and  is  heavily  attacked  by   parasites.  Both  species  are  more  abundant  during  periods  of  dry  weather;  this  is  because  of   the  impact  of  the  weather  on  the  natural  enemies  of  the  moths.  Symptoms  of  A.  pyrogramma   damage  are  common  in  and  around  Honiara,  as  they  are  elsewhere  in  Solomon  Islands.  

Biology and  Life  Cycle   A.  pyrogramma  is  said  to  be  similar  in  appearance  to  A.  arguala.  The  adult  is  5-­‐9  mm  long;  the   female  is  yellowish  brown,  and  the  males  have  white  stripes  on  the  forewings  (photo,  centre).   Eggs  are  laid  on  the  underside  of  the  leaflets,  near  the  tips  and  along  midribs,  singly  or  in  rows.   Larvae  or  caterpillars,  are  green  and  up  to  2  cm  when  mature;  they  spin  a  fine  web  and  shelter   under  this,  feeding  on  the  top  layers  of  the  leaflets,  parallel  to  the  veins.  They  become  active   when  disturbed,  moving  backwards  or  forwards  or  dropping  to  the  ground.  When  mature,   they  spin  a  white  web  and  pupate,  either  on  the  leaflets  or  on  the  undergrowth.  

  1

The photo (above left) is from the Cook Islands Diversity Database. The use of the photos is gratefully acknowledged.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  long,  thin,  grey  patches  of  feeding  on  the  leaflets;  these  are  characteristic  of  the  pest.   Look  for  the  larvae  under  a  thin  web  covering  the  leaflets.  

Management NATURAL  ENEMIES   A  tachinid  fly  has  been  reared  from  A  pyrogramma  in  Solomon  Islands,  and  Waterhouse  in  the   book  Biological  Control  Pacific  Prospects  quotes  others  that  “parasite  introductions  against  A   pyrogramma  have  been  successful”,  without  giving  details.  Many  insects  have  been  introduced   in  other  countries  of  the  region  to  control  A.  arguala;  these  are  mostly  wasps,  belonging  to  the   Braconidea  and  Chalcididae  families  that  attack  larvae  or  pupae.  These  have  come  from  Fiji,   India,  Indonesia,  Papua  New  Guinea  and  Samoa.  Introductions  have  to  be  done  carefully   because  of  the  common  presence  of  hyperparasites;  they  are  insects  that  attack  the  natural   enemies  of  the  flat  moth.       Ants  are  reported  to  destroy  A.  arguala  pupae  and  may  eat  eggs,  and  spiders  sometimes   attack  adults.  In  Fiji,  a  fungus  destroyed  a  high  proportion  of  the  pupae,  and  also  killed  the   larvae  and  adults.  Although  the  natural  enemies  are  not  known  in  Solomon  Islands,  they  are   likely  to  be  similar  to  those  of  A.  arguala  elsewhere.  

CULTURAL CONTROL   None  recommended.  

RESISTANT VARIETIES   None  reported.  

CHEMICAL CONTROL   •

Insecticides are  not  recommended  for  the  control  of  this  insect,  although  they  may  be   useful  on  seedlings.  In  the  normal  situation,  natural  enemies  of  the  flat  moth  keep  the  pest   under  control.  If  serious  outbreaks  do  occur,  the  use  of  pesticides  might  be  tempting,  but   are  more  likely  to  delay  a  return  to  biological  control.  Additionally,  insecticides  are  difficult   to  apply  to  mature  palms  as  well  as  being  ineffective.     If  insecticides  were  required  on,  say,  seedlings  in  the  nursery,  use  malathion  or  synthetic   pyrethroids,  such  as  lambda  cyhalothrin  or  permethrin.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Coconut Flat  Moth  

Extension Fact  Sheet  

65

Common  name:  Coconut  flat  moth   Scientific  name:  Agonoxena  sp.  The  main  pest  species  of  other  Pacific  Island  countries  is  A.   argula  (photo,  centre1);  but  this  is  not  present  in  Solomon  Islands.  A.  pyrogramma  is  present.  It   is  native  to  Solomon  Islands.     Hosts:  Coconuts  and  other  palms.    

Damage The  larvae  of  the  flat  moth  (photo,  centre)  do  the  damage  by  eating  mainly  the  lower  surface   of  the  leaflets.  They  make  lines  1-­‐2  mm  wide  and  2-­‐3  cm  long  near  the  mid-­‐rib;  the  damaged   lines  are  light  grey  (photos,  left  &  right).  There  is  no  evidence  that  coconut  production  is   affected  by  the  damage,  although  the  leaves  can  look  ragged.  However,  it  is  possible  that  the   growth  of  seedlings  may  be  slowed  by  the  attack.     A.  pyrogramma  does  not  do  nearly  as  much  damage  as  A.  arguala,  and  is  heavily  attacked  by   parasites.  Both  species  are  more  abundant  during  periods  of  dry  weather;  this  is  because  of   the  impact  of  the  weather  on  the  natural  enemies  of  the  moths.  Symptoms  of  A.  pyrogramma   damage  are  common  in  and  around  Honiara,  as  they  are  elsewhere  in  Solomon  Islands.  

Biology and  Life  Cycle   A.  pyrogramma  is  said  to  be  similar  in  appearance  to  A.  arguala.  The  adult  is  5-­‐9  mm  long;  the   female  is  yellowish  brown,  and  the  males  have  white  stripes  on  the  forewings  (photo,  centre).   Eggs  are  laid  on  the  underside  of  the  leaflets,  near  the  tips  and  along  midribs,  singly  or  in  rows.   Larvae  or  caterpillars,  are  green  and  up  to  2  cm  when  mature;  they  spin  a  fine  web  and  shelter   under  this,  feeding  on  the  top  layers  of  the  leaflets,  parallel  to  the  veins.  They  become  active   when  disturbed,  moving  backwards  or  forwards  or  dropping  to  the  ground.  When  mature,   they  spin  a  white  web  and  pupate,  either  on  the  leaflets  or  on  the  undergrowth.  

  1

The photo (above left) is from the Cook Islands Diversity Database. The use of the photos is gratefully acknowledged.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  long,  thin,  grey  patches  of  feeding  on  the  leaflets;  these  are  characteristic  of  the  pest.   Look  for  the  larvae  under  a  thin  web  covering  the  leaflets.  

Management NATURAL  ENEMIES   A  tachinid  fly  has  been  reared  from  A  pyrogramma  in  Solomon  Islands,  and  Waterhouse  in  the   book  Biological  Control  Pacific  Prospects  quotes  others  that  “parasite  introductions  against  A   pyrogramma  have  been  successful”,  without  giving  details.  Many  insects  have  been  introduced   in  other  countries  of  the  region  to  control  A.  arguala;  these  are  mostly  wasps,  belonging  to  the   Braconidea  and  Chalcididae  families  that  attack  larvae  or  pupae.  These  have  come  from  Fiji,   India,  Indonesia,  Papua  New  Guinea  and  Samoa.  Introductions  have  to  be  done  carefully   because  of  the  common  presence  of  hyperparasites;  they  are  insects  that  attack  the  natural   enemies  of  the  flat  moth.       Ants  are  reported  to  destroy  A.  arguala  pupae  and  may  eat  eggs,  and  spiders  sometimes   attack  adults.  In  Fiji,  a  fungus  destroyed  a  high  proportion  of  the  pupae,  and  also  killed  the   larvae  and  adults.  Although  the  natural  enemies  are  not  known  in  Solomon  Islands,  they  are   likely  to  be  similar  to  those  of  A.  arguala  elsewhere.  

CULTURAL CONTROL   None  recommended.  

RESISTANT VARIETIES   None  reported.  

CHEMICAL CONTROL   •

Insecticides are  not  recommended  for  the  control  of  this  insect,  although  they  may  be   useful  on  seedlings.  In  the  normal  situation,  natural  enemies  of  the  flat  moth  keep  the  pest   under  control.  If  serious  outbreaks  do  occur,  the  use  of  pesticides  might  be  tempting,  but   are  more  likely  to  delay  a  return  to  biological  control.  Additionally,  insecticides  are  difficult   to  apply  to  mature  palms  as  well  as  being  ineffective.     If  insecticides  were  required  on,  say,  seedlings  in  the  nursery,  use  malathion  or  synthetic   pyrethroids,  such  as  lambda  cyhalothrin  or  permethrin.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Saissetia on  Soursop  

Extension Fact  Sheet  

66

Common  names:  Hemispherical  scale,  Brown  coffee  scale                                                                           Scientific  name:  Saissetia  sp.  There  are  three  species  of  Saissetia  recorded  from  Solomon   Islands,  so  it  is  not  possible  to  be  sure  about  the  one  on  Annona  pictured  below.  However,  the   species  most  often  recorded  on  Annona  in  the  South  Pacific  is  S.  coffeae,  and  this  species  is   recorded  on  that  host  in  Solomon  Islands.  The  description  below  is  for  S.  coffeae.   Hosts:  Soursop,  coffee,  citrus,  guava  and  ornamental  plants,  especially  cycads  and  ferns.  In   Hawaii,  it  is  reported  on  orchids.    

Damage Damage  is  done  in  three  ways:   • Injection  of  a  toxin  as  the  scale  feeds  causing  spots  on  the  foliage;   • Direct  feeding  causes  leaves  to  be  deformed,  die  early,  or  wilt,  depending  on  the  host.   Infested  fruits  of  soursop,  for  instance,  are  smaller  than  normal  due  to  the  scales’  feeding;   • Sooty  moulds  develop  which  reduce  photosynthesis,  and  plant  vigour.  Sooty  moulds  are   fungi  that  grow  on  honeydew,  the  sugary  substance  discharged  by  sap-­‐sucking  insects,  for   instance  aphids  and  some  scale  insects,  as  they  feed  (see  Fact  Sheet  no.  51).    

Biology and  Life  Cycle   Females  do  not  mate,  males  have  not  been  found.  About  500  eggs  are  laid  under  the  body  of   the  female,  so  they  are  protected.  After  hatching,  the  first  immature  stage,  the  crawlers,  walk   about  to  find  a  place  to  feed.  Crawlers  can  also  spread  on  the  wind,  as  well  as  planting   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   materials,  and  even  on  animals,  including  human  beings.  There  are  two  other  immature  stages   before  the  adult  stage.  All  stages  are  capable  of  movement,  until  the  time  when  eggs  are  laid.   The  adults  live  for  about  8  days.  The  scale  is  said  to  prefer  hot,  dry  conditions,  so  climate   change  may  favour  it.    

Detection and  Inspection   Look  for  the  shiny,  brown,  dome-­‐shaped  adult  scales,  round  to  oval,  about  2  mm  across,  most   noticeable  on  the  midrib  on  the  undersides  of  leaves,  on  the  stems  and  fruits.  They  also  occur   on  fruit  stalks.  Look  for  sooty  moulds  on  leaves,  and  especially  look  for  ants.  

Management The  scale  remains  attached  to  stems,  branches  and  fruits  even  after  death.  So,  it  is  important   to  find  out  if  the  scales  are  alive  or  not.  Look  to  see  if  the  infestation  is  spreading  before   applying  any  management  practices.      

NATURAL ENEMIES   There  are  a  large  number  of  parasitoids  and  predators  known  that  attack  S  coffeae,  but  which   ones  are  present  in  Solomon  Islands  is  not  known.  Most  of  the  parasitoids  are  tiny  wasps,  too   small  to  be  seen  easily  by  the  naked  eye.  (A  parasitoid  is  like  a  parasite  -­‐  which  lives  off  its  host   –  but  in  this  case  it  eventually  kills  its  host).        

CULTURAL CONTROL   • • •

Prune infested  stems,  branches  and  fruits  and  destroy  them;   Apply  mulch,  manure  or  synthetic  fertilizers  to  assist  plant  vigour;   Destroy  ant  nests  with  boiling  water,  without  damaging  the  plants  infested  with  the  scale   insect;  without  the  ants,  parasitoids  and  predators  will  bring  about  natural  control  of  the   scale  insect;   For  trees,  prune  low  branches  and  remove  weeds  to  stop  ants  reaching  leaves  and  fruits.    

CHEMICAL CONTROL   Chemical  control  is  not  recommended  because  of  the  waxy  surface  of  the  scale.  Also,   insecticides  are  likely  to  kill  any  parasitoids  and  make  biological  control  ineffective.    However,   if  they  are  needed,  either  to  kill  the  scale  or  ants,  do  the  following:   • Use  soap  sprays  (5  tablespoons  of  soap  in  4  litres  water),  or  white  oil  to  kill  the  scale   insects.  These  sprays  work  by  blocking  the  breathing  holes  of  insects  causing  suffocation   and  death.  Spray  undersides  of  leaves:  the  oils  must  contact  the  insects;   • White  oil  (petroleum  jelly)  can  be  obtained  as  a  commercial  product  or  made  by  mixing   together:  1  cup  cooking  oil;  2  cups  water;  1  teaspoon  dishwashing  liquid.  Dilute  the   mixture  at  3  teaspoons  per  half  a  litre  of  water  and  spray  on  the  infested  leaves.  The   addition  of  malathion  is  useful  against  scales  insects;   • A  second  application  of  soap  or  white  oil  may  be  necessary  after  3-­‐4  weeks;   • To  kill  ants,  use  synthetic  pyrethroids  (for  example,  lambda  cyhalothrin  or  cypermethrin);   these  insecticides  may  also  be  tried  against  scale  insects  as  they  are  likely  to  be  effective   against  crawlers,  but  only  after  other  measures  have  failed,  because  they  are  more  likely   to  kill  the  scale  insects’  natural  enemies.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Betel Nut  “Disease”    

Extension Fact  Sheet  

67

Common  name:  There  is  none;  this  disease  occurs  only  in  Reef  Islands,  and  only  recently.  It   has  not  been  reported  elsewhere  in  Solomon  Islands,  or  in  other  parts  of  the  world   Scientific  name:  There  is  none,  as  the  cause  of  the  death  of  betel  nuts  is  uncertain.   Host:  Betel  nut  (Areca  catechu).  The  susceptibility  of  other  Areca  species  and  related  palms  in   the  Reef  Islands  is  unknown.      

Damage The  disease  appeared  in  about  1975,  perhaps  earlier.  It  causes  a  lethal  condition,  commonly   found  on  mature  palms  about  to  bear  fruit,  some  younger.  Consequently,  betel  nut  production   in  the  Reef  Islands  is  low,  and  nuts  are  imported  from  adjacent  islands  to  satisfy  local  demand.    

Biology and  Life  Cycle   Palms  as  small  as  2  m  show  the  disease,  but  usually  they  are  older  and  taller.  Small  yellow   spots  occur  on  the  leaves,  first  on  leaves  six  or  seven  (photo,  top  left).  As  the  leaves  age,  the   spots  become  irregularly  oval,  approximately  1-­‐2  cm  wide,  longer  parallel  to  the  length  of  the   leaf,  and  faintly  zoned.  Spots  on  the  oldest  leaves  join  together  and  the  leaf  becomes  yellow   and  dies  prematurely.     Affected  palms  show  one  or  several,  red,  vertical  lines  of  rot,  1-­‐2  cm  wide,  of  varying  length   below  the  oldest  leaf  sheath  (photo,  top  right).  These  decayed  areas,  which  often  have  yellow   margins,  extend  internally  through  the  vascular  tissues  to  the  pith  (photo,  top  centre).  The   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   lines  of  rot  gradually  narrow  from  one  leaf  to  the  next  and  end  as  faint  red  line  at  the  base  of   the  youngest  leaf.  Where  the  lines  of  rot  extend  to  the  soil  they  attract  colonies  of  termites.         As  the  condition  progresses,  leaves  become  fewer  and  shorter,  and  then  production  ceases.     Often,  the  last  leaf  is  seen  like  a  short  fan  at  the  top  of  the  palm  (photo,  lower  left).  At  this   stage,  the  inner,  unexposed  leaves  show  extensive  decay,  including  cavities  filled  with  large   amounts  of  gum  (photo,  lower  centre).  Continued  deterioration  of  the  shoot  and  young  leaves   results  in  death  of  the  palm.  On  mature  palms,  flower  buds  rot  while  still  in  the  axils  of   unopened  leaves  (photo,  lower  right),  and  those  that  have  grown  normally  are  shrunken  and   without  nuts.       Isolations  from  the  shoot  tips  yielded  various  fungi,  with  Colletotrichum  being  common.   However,  this  was  not  thought  to  be  the  cause  of  the  disease.  In  the  early  1980s,  Three   samples  of  betel  nut  were  sent  to  the  Department  of  Crop  Protection,  Waite  Campus,   University  of  Adelaide,  together  with  samples  of  coconuts  (9)  and  sago  palm  (1).    All  were   tested  using  molecular  probes  for  Cococnut  cadang-­‐cadang  viroid,  and  all  were  found  to   contain  CCCVd-­‐related  bands  when  their  nucleic  acids  were  analysed,  but  it  was  not  possible   to  relate  the  bands  with  symptoms  because  of  the  small  number  of  samples.  Cause  of  the   disorder  remains  unknown.  

Detection and  Inspection   Look  for  dead  and  dying  palms.  Look  for  red  streaks  on  the  trunks  below  the  leaf  sheaths,   some  extending  to  soil  level.  Look  for  inner  trunk  decay  extending  to  the  pith,  signs  of  black,   decayed,  flower  buds,  and  often,  but  not  always,  spotting  on  the  older  leaves.  If  in  doubt,  trace   the  red  streaks  to  the  shoot  tip  by  removing  the  leaves,  and  notice  the  necrosis  and  gum.    

Management QUARANTINE   There  are  no  internal  laws  restricting  the  movement  of  planting  material  between  islands  of   the  country.  However,  as  there  is  little  knowledge  about  the  cause  of  this  disease  and  its   spread,  people  in  Reef  islands  should  be  advised  not  to  transfer  propagating  material  -­‐  seed  as   well  as  seedlings  -­‐  to  any  other  part  of  Solomon  Islands.    

RESISTANT VARIETIES   None  are  known.  Coconuts  seem  unaffected  by  the  disease.  Speculation  that  the  disease  was   the  same  as  that  causing  Coconut  foliar  decay  (associated  with  a  virus)  in  Vanuatu,  was  not   borne  out  by  investigation,  although  the  vector  of  the  Vanuatu  disease,  Myndus  taffini,  was   found  on  coconuts  in  the  Reefs  Islands,  the  only  place  outside  Vanuatu  where  it  is  known  to   occur.  The  idea  was  that  CFD  was  the  reason  for  the  absence  of  betel  nut  in  Vanuatu,  and  had   now  spread  to  further  along  the  Vanuatu-­‐Solomon  Islands  archipelago,  destroying  betel  nut  in   the  process.  To  check  this,  three  varieties  susceptible  to  CFD  -­‐  Malayan  Dwarf,  Rennell  and   Malayan  Dwarf  x  Rennell  hybrid,  plus  the  local  tall  of  Reef  Islands  -­‐  were  planted  at  Otello   village  in  1980.  No  symptoms  of  CFD  were  recorded  on  these  coconuts.    

CHEMICAL CONTROL   Chemical  control  is  not  appropriate  for  this  disease  in  the  absence  of  any  knowledge  of  its   cause  or  method  of  spread.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cassava Green  Mottle    

Extension Fact  Sheet  

68

Common  name:  Cassava  green  mottle  virus   Scientific  name:  Cassava  green  mottle  ‘nepovirus’.   Hosts:  It  is  only  known  from  cassava,  and  only  from  Choiseul,  nowhere  else  in  the  world.  In  the   lab,  several  plant  species  have  been  infected  with  this  virus;  these  species  are  known  as   ‘indicator’  plants  and  are  used  to  identify  and  characterise  viruses:  Chenopodium,  Nicotiana   (tobacco),  Phaseolus  (French  bean),  Cucumis  (cucumber),  Ricinus  (castor  oil)  and  Solanum   (potato).  Interestingly,  Ipomoea  (sweet  potato)  was  also  infected  in  these  tests,  giving  a   ‘symptomless,  systemic  infection’.  But  whether  or  not  infection  occurs  in  the  field  is  unknown.    

Damage  

Surveys on  Chosieul  showed  that  the  disease  is  present  in  most  plantings,  but  the  number  of   infected  plants  is  low.  Cuttings  taken  from  diseased  plants  are  much  slower  to  develop  than   those  from  plants  without  symptoms  during  the  previous  9  months;  differences  in  height  can   be  seen  at  4  months,  but  they  are  much  less  at  harvest  at  8  months.  Weight  of  stems  and   edible  roots  of  diseased  plants  are  half  those  planted  with  healthy  cuttings.  However,  farmers   usually  plant  three  cuttings  per  mound,  so  any  that  stay  healthy  have  more  space  and   nutrients  and  make  up  for  the  loss  in  yield  from  those  that  are  diseased.  

Biology and  Life  Cycle   Young  leaves  are  puckered  with  faint  (photo,  right)  to  distinct  yellow  spots  and  green  patterns   (mottles),  and  twisted  margins  (photo,  left).  Usually,  the  shoots  recover  from  the  symptoms   and  appear  healthy.  Occasionally,  plants  become  severely  stunted,  edible  roots  are  absent  or,   if  present,  small  and  woody  when  cooked.       In  the  lab,  the  virus  can  be  passed  between  plants  in  sap,  and  also  in  seed.  Thirty  percent  of   the  seed  of  infected  tobacco  plants  was  infected.  Whether  it  also  spreads  in  seed  of  cassava  is   unknown.  Seed  is  not  used  for  growing  cassava,  so  spread  on  Choiseul  is  most  likely  in   diseased  cuttings.  However,  there  are  other  possibilities.         AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   In  a  trial  on  Choiseul,  4%  of  plants  grown  from  cuttings  taken  from  Guadalcanal  became   diseased  within  250  days  from  planting.  How  infection  occurred  is  not  known,  but  there  are   several  possibilities.  The  collision  of  plants  caused  by  wind  may  have  transferred  sap  between   those  infected  and  healthy.  There  is  also  the  possibility  of  spread  by  nematodes  and  pollen.   The  virus  is  thought  to  be  a  member  of  the  nepovirus  group,  and  members  of  this  group  are   spread  in  these  ways.    

Detection and  Inspection   Look  for  yellow  patterns  on  the  leaves,  from  small  dots  to  irregular  patches  of  yellow.  Look  for   leaf  margins  that  are  distorted.  The  plants  may  be  stunted.  

Management QUARANTINE   Surveys  carried  out  in  adjacent  Shortland  Islands  in  the  late  1970s  failed  to  find  the  disease,   and  people  were  made  aware  of  the  danger  of  planting  cuttings  taken  from  Choiseul.  There   are  no  internal  laws  restricting  the  movement  of  planting  material  between  islands  of  the   country,  so  compliance  is  voluntary.  However,  raising  people’s  awareness  about  the  disease,   its  potential  and  method  of  spread,  should  be  done  from  time  to  time.  

CULTURAL CONTROL   Cultural  control  is  very  important,  and  is  the  main  method  of  reducing  the  impact  of  this   disease:     • Take  cuttings  for  propagation  only  from  plants  that  are  free  from  symptoms  and  which,  at   harvest,  produced  high  yields  of  edible  roots;   • Remove  plants  with  symptoms  as  soon  as  they  are  seen,  and  burn  them.  DO  NOT  wait  until   harvest,  as  by  then  the  plants  may  have  recovered  from  symptoms  and,  unless  marked,   difficult  to  identify  as  infected.  

RESISTANT VARIETIES   None  are  known.    

CHEMICAL CONTROL   Chemical  control  is  not  appropriate  for  this  disease,  especially  as  the  method  of  spread  is  not   known.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Coconut Basal  Stem  Break    

Extension Fact  Sheet  

69

Common  names:  Coconut  basal  stem  break  in  Solomon  Islands,  Lethal  bole  rot  in  Kenya  and   Tanzania   Scientific  name:  Marasmiellus  cocophilus.   Hosts:  Coconut,  Cynodon  dactylon  (Bermuda  grass),  Echinochloa  colona  (junglerice),  Eleusine   indica  (goose  grass),  found  in  the  nursery  of  Levers  Pacific  Plantations  Ltd.,  Russell  Islands.    

Damage Only  one  outbreak  has  been  recorded  in  Solomon  Islands,  but  the  consequences  were   considerable.  The  fungus  was  first  observed  in  August  1978  when  a  few  8-­‐9-­‐month-­‐old   Malayan  Dwarf  x  Rennell  coconut  seedlings  in  the  Yandina  nursery  snapped  at  the  junction  of   stem  and  nut.  In  March  the  following  year,  about  7,000  seedlings  were  affected.     Some  6000  seedlings  that  appeared  healthy  were  transplanted  to  the  field,  but  many   developed  symptoms  similar  to  those  in  the  nursery.  Small  leaves  developed  which  started  to   unfurl  before  they  were  fully  emerged.  However,  few  of  the  transplanted  palms  died.  Most   began  to  recover  5-­‐6  months  after  planting  when  new  uninfected  roots  were  produced  and   new  leaves  developed  which  were  progressively  more  normal  in  appearance.     In  East  Africa,  death  of  palms  up  to  8  years  old  was  reported  in  the  late  1960s,  with  seedlings   being  highly  susceptible  on  transfer  to  the  field,  with  losses  of  over  90  per  cent  in  some  areas.  

Biology and  Life  Cycle   Premature  death  of  the  oldest  two  or  three  leaves  is  the  first  symptom;  later,  white  fungal   threads  and  toadstools  appear  at  the  base  of  the  petioles,  on  top  of  the  seednut  (photo,  left).   As  the  fungus  progresses,  successively  younger  leaves  are  infected,  brown  rots  and  cracking   occurs  in  the  leaf  bases,  and  isolated  rots,  1-­‐1.5  cm  deep,  with  shallow,  reddish-­‐brown   margins,  extend  into  the  bole.  Root  decay  is  not  extensive,  although  new  roots  that  penetrate   the  decayed  leaf  junction  of  the  petioles  and  the  seednut.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Similar  symptoms  occurred  in  those  seedlings  planted  in  the  field.  Rots  were  also  present  in   the  swollen  leaf  bases,  roots  decayed,  mycelium  and  toadstools  were  present,  and  because  the   roots  were  destroyed,  leaves  were  small.   In  East  Africa,  root  infections  of  seedlings  leads  to  rapid  infection  of  the  stem  and  death.  On   older  palms,  leaves  wilt,  and  remain  as  a  'skirt'  around  the  trunk,  the  spear  leaf  dies  and  a  foul-­‐ smelling  soft  rot  develops.  A  dry,  reddish-­‐brown  rot  with  a  yellow  margin  is  typically  present  at   the  base  of  the  bole.  Cavities  within  these  areas  of  rot  are  lined  with  mycelium  in  young  palms,   2-­‐4  years  old,  but  this  is  rare  in  4-­‐6-­‐year-­‐old  palms,  and  they  are  absent  in  mature  palms.   Toadstools  commonly  occur  on  exposed  roots,  leaf  bases  of  seedlings  and  on  the  soil  surface   around  holes  where  diseased  palms  had  been  removed  2  years  previously.   Little  is  known  about  the  method  of  infection  and  spread  of  the  fungus  in  Solomon  Islands.  On   one  occasion,  toadstools  were  detected  on  seednuts  taken  from  the  outbreak  area  to  another   destination  within  the  country,  suggesting  the  fungus  is  seedborne.  By  contrast,  in  East  Africa,   spread  is  said  to  occur  through  soil,  root  contact  between  palms,  infected  coconut  debris  and   probably  by  air-­‐borne  spores.  Infection  also  occurs  via  wounds.  

Detection and  Inspection   Look  for  outer  leaves  of  seedlings  that  are  dying  early,  swollen  leaf  bases,  with  cracks,  rots,   fungal  threads  and  small  white  toadstools,  leading  to  a  stem  break  between  leaves  and  roots.      

Management QUARANTINE   After  the  outbreak  in  Yandina,  and  because  the  fungus  was  reported  to  cause  a  lethal  disease,   the  movement  of  seednuts  from  the  Russell  Islands  was  prohibited.  In  1986,  the  situation  was   reassessed,  and  the  quarantine  removed.  The  reasons  for  this  were  as  follows:     • Basal  stem  rot  had  not  occurred  in  Solomon  Islands  since  1979  (although  toadstools  could   still  be  found  on  grasses  in  the  nursery);   • The  condition  had  not  been  consistently  reproduced  experimentally;     • Palms  planted  in  the  field  from  the  1979  Yandina  nursery  continue  to  appear  normal;     • In  East  Africa,  diseases  similar  to  Coconut  lethal  yellowing  (caused  by  a  phytoplasma)  have   been  found  where  M.  cocophilus  was  reported  previously.    

CULTURAL CONTROL   •

The complete  removal  of  the  husk  is  effective  in  preventing  the  fungus  from  colonising   seedlings,  but  some  varieties  (e.g.  the  Malayan  Dwarf  x  Rennell  hybrid)  do  not  tolerate  this   treatment  and  rot  when  planted;     Control  weeds  in  the  nursery  and  trim  roots  that  extended  beyond  the  polythene  bags  to   prevent  infection  as  they  grow  into  the  soil.  

CHEMICAL CONTROL   Seed  treatment  should  always  be  considered  as  a  precautionary  measure  whenever  seednuts   are  being  moved  between  countries,  or  between  areas  within  countries  if  coconut  diseases  are   not  well  distributed.  Seednuts  should  be  taken  directly  from  the  palm,  partially  dehusked  by   trimming  at  the  top  and  three  sides  and  dipped  in  an  appropriate  fungicide  for  15  minutes.  The   addition  of  a  wetting  agent  is  considered  beneficial.  The  fungicide  Calixin  (tridemorth)  was   used  in  Solomon  Islands.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Marasmiellus rots    

Extension Fact  Sheet  

70

Common  names:  Coconut  pre-­‐emergence  shoot  rot,  Coconut  embryo  rot,  Banana  sheath  rot,   Taro  corm  rot   Scientific  name:  Marasmiellus  inoderma  (previously  known  as  M.  semiustus).   Hosts:  Banana,  coconut  and  taro  causing  minor  diseases.  

Damage On  banana:  Outer  leaf  sheaths  and  leaf  bases  wither  and  decay,  leaves  are  slow  to  emerge  and   are  stunted  (photo,  top  centre).  White  or  pink  fungal  growth  commonly  occurs  in  large   irregular  patches  between  the  leaf  sheaths.  In  wet  weather,  toadstools  develop  on  the  lower   parts  of  the  stem  (photo,  top  right),  and  on  decaying  leaves  and  other  debris  on  the  soil.  The   roots  may  also  be  attacked.  Overall,  the  damage  is  minor.     On  coconut:  The  fungus  attacks  the  shoot  as  the  seednuts  germinate.  Early  infection  destroys   the  embryo,  leading  to  entry  of  the  nut  cavity  and  the  development  of  a  pinkish-­‐white  fungal   growth  floating  on  the  liquid  endosperm  –  the  milk.  Foul-­‐smelling  secondary  rots  often   develop.  Where  shoots  survive  early  infection,  brown  rots  occur  at  the  base  of  the  leaves  and   stems  often  associated  with  large  amounts  of  white  fungal  growth  (photo,  top  left).  Usually,   seedlings  overcome  the  attack,  but  growth  may  be  slow.  Sometimes,  the  plants  may  be  killed  if   growing  conditions  are  poor.  Toadstools  form  on  the  nut  and  at  the  base  of  the  seedlings.       In  Solomon  Islands,  15%  of  Malayan  Red  Dwarf  seednuts  germinate  on  the  palm,  and  1-­‐2%  are   infected  or  killed  by  M.  inoderma.  Overall,  losses  are  not  high,  and  vary  between  varieties.  By   contrast,  in  Samoa,  losses  of  50%  are  reported  in  the  nursery  of  the  seedgarden  producing   Malayan  Dwarf  x  Rennell  seednuts.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   On  taro:  The  fungus  rots  the  outer  leaves  and  causes  a  shallow  corm  rot,  although  on  over-­‐ mature  plants  the  entire  corm  may  be  decayed  and  filled  with  white  mycelium  (photo,  lower   centre).  Toadstools  are  often  seen  on  the  decaying  petioles  (photo,  lower  left).  The  disease  is   reported  from  the  weather  coast  of  Guadalcanal.  The  number  of  plants  damaged  is  low.  

Biology and  Life  Cycle   Infection  by  the  fungus  occurs  while  the  seednuts  are  attached  to  the  palm.  Most  likely,  it   occurs  as  airborne  spores,  which  grow  through  the  stalk  (or  calyx)  end  of  the  seednut,  colonise   the  fibrous  husks  and  grow  beneath  the  brown  cap  as  it  is  raised  for  germination.  Possibly,   other  seednuts  become  infected  in  the  nursery,  either  by  airborne  spores  or  from  the  fungus   growing  in  the  soil.  Whatever  the  case,  infection  of  the  seednut  leads  to  the  fungus  entering   the  nut,  and  feeding  on  the  endosperm,  that  is,  the  ‘milk’  and  ‘meat’.     Infection  of  banana  and  taro  may  also  occur  from  spores  landing  on  the  older  bottom  parts  of   leaves  as  they  start  to  die  or  through  wounds.  It  is  more  likely  that  fungal  threads  of  the  fungus   are  carried  on  planting  material,  and  grow  slowly  from  the  outer  to  the  inner  leaves  as  plants   develop,  causing  leaf  decay  and  shallow  corm  rots.     Toadstools  are  produced  in  wet  weather,  commonly  on  the  dead  seednuts  in  the  coconut   nursery,  and  on  the  outer  leaves  of  banana  and  taro.  Masses  of  spores  are  released  from  these   toadstools  and  spread  by  wind.    

Detection and  Inspection   Look  for  seednuts  that  do  not  germinate,  remove  the  husk  and  look  for  white  fungal  growth   above  the  germination  pore  or  thick  fungal  mats  inside  the  cavity.  Look  for  early  death  of   leaves  of  banana  and  taro,  and  white  fungal  growth  binding  the  leaves  together.  Look  for   white  or  light  brown  toadstools  on  seednuts,  and  stems  of  banana  and  taro.      

Management CULTURAL  CONTROL   • • •

On coconut,  remove  ungerminated  seednuts  from  nursery  before  toadstools  form;   On  banana,  remove  diseased  plants  and  use  mulches  and  manures  to  promote  vigorous   growth.  Planting  material  should  be  selected  carefully  to  ensure  freedom  from  the  fungus;   Infections  on  taro  are  not  sufficiently  serious  to  need  control  measures,  although  removal   of  disease  plants  should  be  carried  out  to  limit  spread.    

RESISTANT VARIETIES   Local  tall  varieties  are  much  more  resistant  to  the  disease  compared  to  Malayan  Dwarf  and   hybrids  between  them  and  other  varieties.  

CHEMICAL CONTROL   Post-­‐harvest  dips  with  a  range  of  fungicides  have  been  tried  in  both  Solomon  Islands  and   Samoa,  but  none  have  improved  seednut  germination  consistently.  Best  control  has  been   obtained  using  phenyl  mercury  acetate,  a  product  also  found  useful  for  the  control  of   Marasmius  bunch  rot  of  oil  palm,  but  less  toxic  alternatives,  for  example,  benodanil,  have  also   been  used  with  some  success  (in  Samoa).  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Banana Black  Cross    

Extension Fact  Sheet  

71

Common  names:  Banana  black  cross,  Black  cross  disease,  Tar  spot   Scientific  name:  Phyllachora  musicola.   Hosts:  Banana  and  plantain  varieties  only.    

Damage Usually,  the  disease  is  of  minor  importance.  On  susceptible  varieties,  it  is  worse  when  they  are   planted  under  shade.  In  this  case,  the  spots  are  dense,  covering  most  of  the  leaf  surface.   Further  damage  to  the  leaf  occurs  when  the  spots  become  infected  by  Diamond  leaf  spot,   caused  by  the  fungus,  Cordana  musae  (photo,  right).  (See  Fact  Sheet  no.  72  for  symptoms  of   Cordana.)  

Biology and  Life  Cycle   The  spots  are  black,  four-­‐pointed  stars,  up  to  60  mm  long,  most  clearly  seen  on  the  lower   surface  of  older  leaves  (photo,  left).  The  long  axis  of  the  star  is  parallel  to  the  leaf  veins,  that  is,   at  right  angles  to  the  length  of  the  leaf.  The  spots  are  scattered,  but  sometimes  occur  in  large   groups.       A  velvet-­‐like  mass  of  spores  is  produced  on  the  lower  surface  of  the  spots.  The  spores  are   spread  by  rain  and  wind.  This  is  the  asexual  state  of  the  fungus.  Sexual  spores  are  also  formed   in  the  spots,  and  they  also  spread  the  fungus.  

Detection and  Inspection   Look  for  the  characteristic  black,  four-­‐pointed  stars,  on  the  lower  surface  of  older  leaves   (photo,  left),  with  their  longer  axis  parallel  to  the  leaf  veins.  Use  a  microscope  to  see  the   spores  on  the  undersurface  of  the  spots.  Look  to  see  if  the  stars  are  associated  with  large   diamond  spots  of  Cordana.  

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management   CULTURAL  CONTROL   Control  measures  are  unlikely  to  be  needed  against  this  disease.  If  they  are,  priority  should  be   given  to  reducing  shade  levels  or  planting  the  bananas  in  open  ground.  

RESISTANT VARIETIES   Cavendish  varieties  are  resistant.  The  fungus  usually  attacks  cooking  and  ladyfinger  bananas.   Some  of  the  FHIA  varieties  bred  in  Honduras,  Central  America,  and  imported  from  the   Secretariat  of  the  Pacific  Community,  are  susceptible.  In  lowlands  Papua  New  Guinea,  varieties   FHIA  02,  FHAI  17,  FHIA  18  and  FHIA  23  were  susceptible,  with  FHIA  02  moderately  susceptible   (class  3)  on  a  scale  of  1-­‐5,  and  the  others  less  so.  

CHEMICAL CONTROL   The  disease  is  of  minor  importance  in  commercial  varieties  and,  even  in  those  that  are   susceptible,  it  is  not  thought  to  lower  yield  sufficiently  to  need  control  by  fungicides.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cordana Leaf  Spot    

Extension Fact  Sheet  

72

Common  names:  Cordana  leaf  spot,  Diamond  leaf  spot   Scientific  name:  Cordana  musae;  there  is  another  species,  C.  johnstonii,  in  north  Queensland,   Australia.   Hosts:  Banana  and  plantain  varieties  only.    

Damage Usually,  the  disease  is  of  minor  importance  on  Cavendish  bananas,  but  can  sometimes  be   severe  on  plantains,  that  is,  cooking  bananas,  but  it  is  not  likely  to  reduce  yields  to  the  extent   that  control  measures  are  required.    

Biology and  Life  Cycle   The  spots  are  oval  to  diamond-­‐shaped,  up  to  10  cm  long,  and  at  right  angles  to  the  length  of   the  leaf  (photo,  left).  They  are  brown  on  the  upper  surface,  zoned,  with  yellow  margins,  and   grey  to  brown  below.  The  spots  often  merge,  covering  large  areas  of  the  leaf;  this  occurs   particularly  at  the  margin  of  the  leaf  giving  a  band  of  dead  tissue  with  a  zigzag  yellow  border   between  diseased  and  healthy  parts.       Cordana  infection  often  occurs  on  Black  cross  leaf  spots  (photo,  right,  and  Fact  Sheet  no.  71).   This  suggests  that  the  fungus  is  a  weak  pathogen  and  needs  a  wound  to  infect.     Spores  are  produced  on  the  underside  of  the  leaf  in  large  numbers,  and  spread  in  wet,  windy   weather.    

Detection and  Inspection   Look  for  the  diamond-­‐shaped  brown  spots,  with  a  yellow  border,  often  common  along  the   margin  of  the  leaf.  Look  to  see  if  the  spots  are  centred  on  the  star-­‐shaped  spots  of  Phyllachora.    

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management CULTURAL  CONTROL   Control  measures  are  unlikely  to  be  needed  against  this  disease.    

RESISTANT VARIETIES   Cavendish  varieties  are  resistant.  The  fungus  usually  infects  cooking  bananas,  but  the  damage   is  usually  insignificant.  There  is  no  information  on  the  resistance  of  the  FHIA  varieties  bred  in   Honduras,  Central  America,  and  imported  from  the  Secretariat  of  the  Pacific  Community,  to   this  disease.    

CHEMICAL CONTROL   The  disease  is  of  minor  importance  in  commercial  varieties  and,  even  in  those  that  are   susceptible,  it  is  not  thought  to  lower  yield  sufficiently  to  need  control  by  fungicides.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Bacterial Leaf  Streak    

Extension Fact  Sheet  

73

Common  name:  Bacterial  leaf  streak   Scientific  name:  Xanthomonas  vasicola  pv.  holcicola  (previously  known  as  X.  campestris  pv.   holcicola;  X.  holcicola.  Note,  positive  identification  awaits  inoculation  studies.   Hosts:  Sorghum,  millet,  Johnson  grass.  Maize  is  a  minor  host.    

Damage The  spots  and  streaks  merge  to  form  large  dead  areas  on  the  leaves,  usually  beginning  on  the   lower  older  leaves,  and  progressing  upwards.  However,  the  impact  of  the  disease  in  Solomon   Islands  is  unknown,  but  it  seems  that  the  variety  used  for  livestock  feed  matures  before  major   damage  is  done,  and  yields  are  affected.    

Biology and  Life  Cycle   Narrow,  reddish-­‐brown,  2-­‐3  mm  wide,  5-­‐15  mm  long,  somewhat  rectangular,  streaks  appear   on  the  lower  leaves  (photo,  left).  During  wet  weather,  these  merge  to  form  long  irregular   streaks  and  blotches  throughout  all  or  much  of  the  leaf.  The  leaves  die  and  hang  down  around   the  stem  (photo,  right).  Large,  irregular  reddish-­‐brown  to  black  blotches  also  develop  on  the   leaf  bases  and  stems.     The  bacteria  that  cause  the  disease  are  unlikely  to  be  seed  borne  from  studies  done  in  other   countries.  Therefore,  the  most  likely  way  that  the  bacteria  are  spread  is  from  crop  debris  in  the   soil,  and  also  from  wild  grasses;  the  latter  is  the  most  likely  way  for  sorghum  to  become   infected  on  the  Guadalcanal  Plains.     The  bacteria  ooze  from  the  spots  during  wet  weather,  and  are  spread  in  wind  and  rain.  

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  the  reddish-­‐brown,  rectangular  spots  on  the  leaves  that  spread  rapidly  and  join   together,  causing  a  blight,  especially  in  wet  weather.  Identification  of  the  bacterium  requires   isolation  in  the  lab,  and  expert  examination  of  the  bacterial  colonies  using  chemical  tests.    

Management CULTURAL  CONTROL   • • •

After harvest,  destroy  all  the  leaves  and  stems  by  burning.  DO  NOT  leave  the  trash  to  rot  in   the  field,  especially  if  another  crop  is  to  be  planted  on  land  nearby;   DO  NOT  plant  sorghum  on  the  same  land  two  crops  in  succession;   Although  the  bacterium  has  not  been  proven  to  be  seedborne,  it  is  important  to  use   ‘clean’  seed,  that  is,  seed  from  crops  that  were  free  from  the  disease  during  the  previous   crop.    

RESISTANT VARIETIES   There  is  no  information  on  varietal  resistance  of  sorghum  in  Solomon  Islands,  although  there   are  reports  of  resistant  lines  from  other  countries.    

CHEMICAL CONTROL   It  is  not  appropriate  for  this  disease,  especially  as  sorghum  is  not  grown  commercially  in   Solomon  Islands;  it  is  grown  for  village  poultry  projects  where  use  of  chemicals  would  be   uneconomical.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Maize Mosaic  Virus    

Extension Fact  Sheet  

74

Common  name:  Maize  mosaic  virus   Scientific  name:  Maize  mosaic  nucleorhabdovirus.   Hosts:  Maize  and  sweet  corn,  Rottboellia  cochinchensis  (itch  grass).    

Damage  

Plants are  stunted  (photo,  right),  and  either  the  cobs  do  not  develop,  or  they  are  deformed   with  fewer  seeds  than  normal.  However,  the  number  of  plants  infected  with  the  disease  is   usually  quite  small,  perhaps  1-­‐2%;  therefore,  although  individual  plants  may  have  very  low   yields,  plot  yields  (that  is,  yields  per  unit  area)  are  probably  not  reduced  greatly.  Sweet  corn   appears  to  be  more  susceptible  than  maize.    

Biology and  Life  Cycle   Apart  from  stunting,  the  virus  causes  light  green  to  yellow  stripes  along  the  leaves  (photo,   left).  These  stripes  are  either  narrow,  the  width  of  a  single  leaf  vein,  or  in  bands  1-­‐2  cm  wide.       The  virus  particles  are  bullet-­‐shaped  when  seen  under  the  electron  microscope.  The  virus  is   not  seedborne,  nor  is  it  spread  in  infected  plant  material.  It  is  spread  by  planthoppers,   Peregrinus  maidis,  that  live  and  breed  on  maize  and  Rottboellia.  The  planthoppers  feed  on   infected  maize  and  Rottboellia,  acquire  the  virus  and,  after  a  few  days,  during  which  time  the   virus  multiplies,  the  planthoppers  then  spread  the  virus  until  they  die.      

Detection and  Inspection   Look  for  stunted  plants,  often  present  at  or  near  the  borders  of  the  plots.  Look  for  the  yellow   and  green  stripes,  sometimes  running  the  entire  length  of  the  leaves;  these  may  be  narrow,  a   single  line  or  in  bands,  1-­‐2  cm  wide.    Importantly,  look  for  populations  of  planthoppers  in  the  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   ‘funnel’  of  the  young  leaves;  this  is  often  an  indication  that  the  symptoms  are  caused  by  Maize   mosaic  virus.       Another  virus,  Maize  stripe  virus,  causes  similar  symptoms  in  maize  and  Rottboellia,  and  is   spread  by  P  maidis.  However,  this  virus  has  not  been  found  in  Solomon  Islands  or  anywhere   else  in  the  Pacific,  but  is  reported  from  Australia.  Maize  stripe  virus  particles  are  long  flexuous   rods.  

Management CULTURAL  CONTROL   Pull  out  plants  as  soon  as  symptoms  are  seen.  DO  NOT  wait;  otherwise,  the  insects  present  will   breed  and  spread  the  disease.  When  pulling  out  the  plants  grasp  the  young  leaves,  holding   them  together,  preventing  the  insects  within  the  ‘funnel’  of  the  plants  from  escaping.  Put  the   plants  into  a  sack  and  burn  them,  destroying  plants  and  insects.  

RESISTANT VARIETIES   It  is  likely  that  varieties  of  maize  imported  into  Solomon  Islands  are  from  countries  where   maize  and  sweet  corn  have  been  bred  for  resistance  to  this  disease.  

CHEMICAL CONTROL   It  is  not  appropriate  for  this  disease.  Although  insecticides  could  be  used  to  kill  the   planthoppers  that  spread  the  virus,  their  use  would  not  be  economical  as  the  number  of  plants   with  symptoms  is  usually  low.  Removal  of  infected  plants  is  a  better  method  of  control.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Seedling Blight    

Extension Fact  Sheet  

75

Common  name:  Coconut  seedling  blight   Scientific  name:  Bipolaris  incurvata  (previously  known  as  Drechslera  incurvata,   Helminthosporium  incurvatum).   Host:  Coconut.    

Damage The  disease  is  only  of  importance  in  the  nursery;  after  transfer  to  the  field  it  is  rarely   important.  Weak  seedlings,  growing  under  poor  conditions  –  crowding,  poor  nutrition  and  too   much  shade  -­‐  are  most  affected,  but  the  disease  also  damages  those  in  nurseries  that  are  well   maintained.  Infection  causes  leaves  to  dry  up  and  die  early,  and  the  defoliation  slows  growth.  

Biology and  Life  Cycle   The  leaf  spots  are  at  first  small,  oval  and  brown;  later,  they  grow  up  to  15  mm  long,  light   brown  or  grey  in  the  middle  with  a  broad  dark  margin  (photo,  left).  Often  the  spots  join   together  causing  a  leaf  blight  (photo,  right).       Spores  of  the  fungus,  which  are  mostly  formed  on  the  underside  of  the  leaf  spots  during  wet   weather,  are  spread  by  wind.  The  fungus  needs  high  levels  of  relative  humidity  for  sporulation,   and  the  spores  need  dew  or  rain  for  infection.  

Detection and  Inspection   This  is  a  distinctive  disease  on  seedlings,  especially  in  nurseries  where  they  are  crowded   together.  Look  for  large  numbers  of  oval,  brown,  leaf  spots  that  rapidly  expand  becoming  light   grey  in  the  centre,  join  together  and  develop  into  a  blight,  killing  large  areas  of  the  leaves.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management CULTURAL  CONTROL   • •

• •

Make sure  that  the  seedlings  have  the  necessary  conditions  for  rapid  growth,  that  is,   sufficient  water,  correct  nutrition  and  enough  space  to  grow;   In  general,  nitrogen  increases  disease  severity  -­‐  it  has  been  found  to  increase  spore   production  -­‐  and  can,  indirectly,  lead  to  death  of  the  seedlings.  By  contrast,  potassium   increases  leaf  resistance  to  infection,  and  results  in  lower  levels  of  disease;   Plants  in  the  nursery  should  be  adequately  spaced  to  allow  free  movement  of  air  between   them;   Reduce  the  level  of  shade,  or  grow  seedlings  without  shade.  

RESISTANT VARIETIES   None  known  

CHEMICAL CONTROL   Fungicides  should  only  be  considered  after  the  reduction  of  shade  and  the  application  of   fertiliser,  especially  potassium.  If  fungicides  are  required,  use  chlorothalonil,  copper   oxychloride  or  mancozeb.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Tomato Leaf  Mould    

Extension Fact  Sheet  

76

Common  names:  Tomato  leaf  mould,  Leaf  mould,  Tomato  grey  leaf  mould   Scientific  name:  Passalora  fulva  (previously  known  as  Fulvia  fulva,  Mycovellosiella  fulva    and  Cladosporium  fulvum).   Host:  Tomato.    

Damage The  fungus  causes  a  serious  disease  in  the  cooler,  wetter,  highland  areas  of  Solomon  Islands.   The  loss  of  leaves,  from  the  bottom  of  the  plant  upwards,  is  rapid.  Yield  reduction  is  related  to   the  time  of  infection.  If  plants  are  infected  before  fruits  are  formed,  considerable  crop  loss   occurs.  In  severe  cases,  the  flowers  and,  occasionally,  the  fruit  are  attacked.  Infected  flowers   may  fail  to  set  fruit.  Occasionally,  the  fungus  causes  an  internal  blackening  of  the  fruit.     Note,  in  Samoa,  fruit  yields  on  susceptible  varieties  were  tripled  when  the  disease  was   controlled  by  fungicides.     The  disease  is  less  common  in  coastal  areas  in  Solomon  Islands,  where  another  leaf  mould   disease,  Black  Leaf  Mould,  Pseudocercospora  fuligena,  occurs  on  tomatoes.  (See  Fact  Sheet   no.  45  for  details.)  

Biology and  Life  Cycle   Yellow  spots  and  patches  occur  on  the  top  surface  of  the  leaves  with  brown  to  green  spore   masses  on  the  lower  surface  (photos,  left  and  right).  The  diseased  areas  join  together  and  the   leaves  dry  up  and  die.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Survival  between  crops  occurs  in  a  number  of  ways.  The  fungus  survives  as  spores  or  as   mycelium  (the  cotton-­‐like  growth  of  the  fungus)  in  dead  tomato  plants  of  the  previous  crop.  It   is  spread  as  spores  in  air  currents,  by  water  splash,  or  on  tools  and  clothing.  There  is  a   possibility  that  spread  also  occurs  by  insects  and  on  seed.    

Detection and  Inspection   Look  for  the  yellow  spots  and  rapidly  developing  irregular  patches  on  the  upper  surfaces  of  the   lower  leaves,  with  brown  to  green  areas  on  the  under  surface.  Look  for  plants  where  leaves   dry  up  and  die  rapidly.  

Management CULTURAL  CONTROL   • • •

Remove infected  lower  leaves  as  soon  as  the  first  three  or  four  fruit  trusses  (bunches)  have   been  picked;   After  harvest,  remove  and  destroy  (burn)  all  plant  debris;   It  is  not  known  for  certain  whether  seed  is  important  in  the  spread  of  the  fungus.   However,  hot  water  treatment  has  been  used  as  a  method  of  producing  seed  free  from   contamination  by  fungal  spores.  Seed  is  treated  with  water  for  25  minutes  at  exactly  50°C.   Note,  this  is  not  a  method  that  farmers  would  use,  because  of  the  need  for  a   thermometer.  Also,  treatment  of  seed  by  this  method  would  only  be  done  as  a  last  resort,   after  other  methods  have  been  tried  and  failed.      

RESISTANT VARIETIES   Leaf-­‐mould  resistant  varieties  are  available.  However,  the  fungus  mutates  readily  (there  are  at   least  12  races  of  the  fungus),  and  varieties  may  not  be  resistant  to  them  all.    

CHEMICAL CONTROL The  cool,  wet,  conditions  in  Solomon  Islands  favour  the  disease  such  that  fungicides  are   needed  to  give  adequate  control.  The  products  to  use  are  chlorothalonil  (Bravo),  copper   oxychloride  or  mancozeb.  Treatment  should  start  when  the  yellow  spots  are  first  seen,  and   continue  at  10-­‐14  days  intervals  until  3-­‐4  weeks  before  last  harvest.  It  is  important  to  spray   both  sides  of  the  leaves.     Azole  fungicides  (e.g.,  difenoconazole)  are  recommended  for  control  of  this  disease  in  other   countries.  But  these  are  rarely,  if  ever,  sold  in  Solomon  Islands.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Fiji Disease    

Extension Fact  Sheet  

77

Common  name:  Fiji  disease  of  sugarcane   Scientific  name:  Sugarcane  Fiji  Fiji  disease  virus.   Hosts:  Sugarcane  (Saccharum  officinarum);  Lowland  pitpit  (S.  edule),  and  other  Saccharum   species.    

Damage  

In the  past,  the  virus  has  caused  severe  damage  to  commercial  sugarcane  in  Fiji  and  Australia.   The  epidemics  of  these  two  countries  were  caused  by  planting  large  areas  of  susceptible   varieties.  For  instance,  in  1979,  there  were  70  million  plants  were  present  with  this  virus   disease  in  the  Bundaberg  district  of  Queensland.  In  Solomon  Islands,  the  situation  is  different.   Sugarcane  is  never  planted  in  large  areas;  it  occurs  as  a  few  plants  in  a  garden;  and  the   varieties  may  have  been  selected  for  resistance.  Whatever  the  reason,  the  number  of  plants   affected  is  relatively  low.  It  is  not  a  serious  disease.    

Biology and  Life  Cycle   Sugarcane  Fiji  disease  is  spread  in  Solomon  Islands  by  an  unidentified  species  of  Perkinsiella,  a   planthopper  (photo,  right),  which  breeds  in  the  young  leaves.  The  adult  planthoppers  have   wings,  allowing  them  to  fly  from  diseased  to  health  plants.  All  stages  of  Perkinsiella  are  capable   of  spreading  the  virus.  The  insects  take  in  the  virus  as  they  feed.  The  virus  multiplies  inside  the   insect  and  after  2-­‐4  weeks  incubation  the  insects  can  pass  the  virus  to  healthy  sugarcane.       The  disease  is  also  spread  in  planting  material.  Farmers  do  not  always  realise  that  plants   chosen  for  propagation  are  diseased.  Early  symptoms  are  mild  and  easily  missed.    

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Unusually  for  a  virus,  the  symptoms  include  gall  formation.  Look  for  galls  (outgrowths)  on  the   under  surface  of  the  leaves,  along  the  midrib  and  large  veins;  they  vary  in  size  from  those  that   can  only  just  be  seen  with  the  eye  to  those  that  are  50  mm  long,  2-­‐3  mm  wide  and  1-­‐2  mm   high.  The  galls  are  characteristic  of  the  disease,  and  important  in  distinguishing  Sugarcane  Fiji   disease  from  other  sugarcane  diseases.  Look  for  leaves,  which  are  short,  stiff,  and  horizontal   (photo,  left;  note  the  diseased  plants  on  the  left,  and  healthy  plants  centre  and  right).  The   diseased  plants  look  as  if  cattle  have  eaten  them.  Look  for  stems  where  the  buds  have   developed,  giving  bunches  of  leaves  along  the  stem,  called  a  witches’  broom  effect.       The  virus  can  be  detected  in  ELISA  tests,  and  also  by  molecular  tests  using  PCR.  

Management CULTURAL  CONTROL   • • •

Remove plants  as  soon  as  symptoms  are  seen,  and  burn  them;     DO  NOT  use  any  of  the  stems  from  a  diseased  plant  for  propagation,  even  if  some  stems   appear  healthy;  they  will  develop  the  disease  later;   When  pulling  out  the  plants  look  to  see  if  insects  are  present  in  the  young  leaves;  if  they   are,  hold  the  leaves  together  to  stop  them  from  escaping  and  moving  to  healthy  plants  and   spreading  the  virus.    

RESISTANT VARIETIES   There  are  commercial  varieties  with  resistance  to  the  disease.  However,  it  is  not  clear  whether   there  would  be  any  advantage  in  introducing  them  to  Solomon  Islands.  Nothing  is  known   about  the  resistance  of  the  local  varieties  so  it  is  difficult  to  know  which  ones  to  recommend.  It   is  important  that  if  new  varieties  are  introduced  that  they  are  properly  treated  according  to   the  FAO/IBPGR  Technical  Guidelines  for  the  Safe  Movement  of  Sugarcane  Germplasm.  

CHEMICAL CONTROL   The  use  of  pesticides  is  not  recommended  for  sugarcane  grown  for  household  use.  Costs  are   high,  regular  applications  would  be  needed,  and  farmers  need  training  in  pesticide  application.   The  use  of  pesticides  is  also  potentially  dangerous  to  the  person  applying  them  and  the   environment.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cabbage-­‐heart Caterpillar     Fact  Sheet   Extension  

78

Common  name:  Large  cabbage-­‐heart  caterpillar1   Scientific  name:  Crocidolomia  pavonana.   Host:  Members  of  the  Brassica  family  -­‐  broccoli,  cabbage,  cauliflower,  Chinese  cabbage,   mustard  and  radish.    

Damage The  larvae  or  caterpillars  cause  the  damage.  They  feed  on  all  stages  of  the  plants,  although   they  rarely  attack  seedlings.  Damage  is  often  severe  as  the  caterpillars  feed  on  the  ‘heart’  or   centre  of  plants  (photos).  The  caterpillars  often  occur  with  those  of  Diamond  back  moth.  It  is   second  in  important  to  DBM;  even  a  single  caterpillar  is  capable  of  causing  significant  damage   –  and  therefore  economic  loss  –  at  pre-­‐  and  post-­‐heading  stages.  

Biology and  Life  Cycle   Eggs  are  laid  on  the  underside  of  the  outer  leaves  in  batches  of  10  to  more  than  a  100.  They   are  pale  green  at  first,  becoming  bright  yellow,  and  then  brown  before  hatching.  The  young   caterpillars  are  2-­‐3  mm  at  first,  growing  to  20  mm,  with  white  or  pale  green  stripes  (photo,   right);  the  later  stages  make  thick  webs  over  the  leaves,  and  feed  beneath  them.  The   caterpillars  pupate  in  the  soil.  The  adult  is  light  brown,  just  less  than  20  mm  long  (photo,   below).       The  life  cycle  is  about  22  days  in  the  lowlands,  and  35  days  in  the  highlands.   1

Information in  this  fact  sheet  is  taken  from  the  CABI  Crop  Protection  Compendium,  and  also  from  a  fact  sheet  produced  by  Mike   Furlong,  University  of  Queensland,  Australia.   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection   Look  for  the  egg  masses  on  the  lower  surfaces  of  the  leaves,  along  the  midrib  and  main  veins.   Look  for  caterpillars  at  the  centre  of  cabbages  with  white  or  pale  green  stripes;  look  for  the   presence  of  webbing  and  faeces  (small  brown  droppings).  

Management NATURAL  EMEMIES   There  is  no  information  about  natural  enemies  in  Solomon   Islands.  A  Braconid  wasp  and  a  Tachinid  fly  occur  in  Papua  New   Guinea,  but  neither  was  able  to  prevent  high  levels  of  damage.   It  is  likely  that  these  natural  enemies  as  well  as  ladybeetle  and   lacewing  larvae  occur  in  Solomon  Islands,  though  this  has  not   been  confirmed.  

CULTURAL CONTROL   • • • •

Check seedlings  in  the  nursery  for  egg  masses  and  young   caterpillars;  If  found,  remove  the  leaves  or  the  entire  plants  and  destroy  them;   Hand-­‐pick  larvae  from  plants  in  the  field  when  numbers  of  insects  are  low;   Grow  plants  under  nets  or  in  screen  houses,  if  resources  allow;   Use  mustard  as  a  trap  crop,  planting  it  as  a  companion  crop  between  rows  of  cabbages   and  other  Brassica  species;  mustard  is  a  preferred  host  for  this  insect  pest  and  protects  the   cabbages  from  destruction;   Destroy  crop  residues  after  harvest,  and  weeds  in  the  Brassica  family  before  planting  and   during  the  cropping  period.  

CHEMICAL CONTROL   Use  Bacillus  thuringiensis  (Bt),  but  note  the  following:   • Good  plant  coverage  is  needed  as  the  insecticide  has  to  be  eaten  by  the  caterpillars  to  kill   them;   • Eggs  are  not  susceptible  to  Bt;   • Use  Bt  as  soon  as  damage  is  seen;   • Small  larvae  are  more  susceptible  than  fully  grown  ones  to  Bt.     Avoid  using  broad-­‐spectrum  insecticides  (such  as  pyrethroids  and  organophosphates)  as  they   will  kill  natural  enemies.    

       

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Hibiscus Ringspot  Virus    

Extension Fact  Sheet  

79

Common  name:  There  is  no  internationally  accepted  common  name,  but  Hibiscus  ringspot   virus  is  suggested  here   Scientific  name:  Hibiscus  chlorotic  ringspot  carmovirus  (HRSPV)1.  The  virus  has  small  (28  nm),   spherical  particles.   Hosts:   Sliperi  kabis  (Abelmoschus   manihot),  and   the   ornamental   Hibiscus   rosa-­‐-­‐-­‐sinensis.  A   number  of  plant  species  used  for   virus  detection  in  labs  are   hosts,  including  cotton  and   French  bean,  but  there  is  not  record  of  these  plants  being  infected  in  the  field.    

Damage   Symptoms  are  common  wherever  sliperi  kabis  is  grown,  but  there  is  no  information  on  the   effect  of  the  virus  on  plant  growth.  It  is  probably  small.  Patches  of  light  green  occur,  scatted   amongst  the  normal  dark  green  of  the  leaves.  These  areas  are  sometimes  large,  and  easily   seen  (photo),  or  very  faint,  and  difficult  to  detect.  Patterns  of  pale  and  dark  green  areas  are   called  mosaics  or  mottles.  The  word  chlorotic  in  the  name  of  the  virus  means  loss  of  the   normal  green  colour.  Ringspots  occur  on  Hibiscus,  but  are  uncommon  on  sliperi  kabis.  The   ringspots  are  pale  green  circles,  2-­‐3  mm  diameter.    

Biology and  Life  Cycle   The  virus  is  spread  in  cuttings  used  for  planting  and  this  is  the  main  method  of  spread.  The   virus  can  also  spread  in  sap  from  infected  plants  which  make  contact  with  with  healthy  leaves.   Transfer  on  knives  and  secateurs  is  a  possibility.  However,  the  importance  of  spread  in  sap  in   these  ways  is  unknown.     1

The  virus  was  first  found  in  Hibiscus,  and  then  found  throughout  the  Pacific  in  Abelmoschus,  during  UNDP/FAO  surveys  in  the   1980s.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S     The  virus  is  not  spread  in  seed.  Other,  similar  viruses  are  spread  by  beetles,  and  also  by  a   soilborne  fungus,  but  their  importance  in  the  spread  of  HCRV  is  also  unknown.    

Detection and  Inspection   Look  for  the  pale  green  patterns  on  the  leaves,  but  note  that  plants  can,  at  times,  appear   symptomless;  this  means  that  the  leaves  can  appear  healthy,  even  though  they  are  infection   by  the  virus.  Look  for  ringspots  on  Hibiscus.  

Management Little  is  known  about  the  effect  of  the  virus  on  plant  growth.  Damage  is  probably  slight.   Growers  rarely  acknowledge  the  symptoms  of  this  disease,  suggesting  that  its  overall  impact  is   small.  However,  there  is  always  the  possibility  of  more  severe  symptoms  if  plants  become   infected  by  HCRSV  and  other  types  of  viruses.    

PATHOGEN-­‐TESTED PLANTS   Tissue  culture  can  be  used  to  produce  plants  that  are  free  from  virus.  The  technique  involves   growing  the  smallest  part  of  the  shoot  tip  where  leaves  and  stems  are  formed.  The  shoot  tip  is   cut  out,  placed  on  a  sterile  tissue  culture  medium  and  grown  into  a  new  plant.  If  done   properly,  there  is  a  chance  that  the  plant  is  free  of  virus,  but  to  make  sure  it  has  to  be  tested.     Sliperi  kabis  plants  from  Papua  New  Guinea  and  Fiji  are  available  from  the  SPC  Centre  for   Pacific  Crops  and  Trees.  The  plants  from  Papua  New  Guinea  were  introduced  to  Fiji  as  seed,   and  then  tested  for  quality,  before  being  treated  to  remove  HCRSV.  The  plants  were  grown   from  meristems  and  tested  for  virus.  

SEED HCRSV  is  not  seedborne,  so  plants  from  seed  will  be  free  from  virus.  However,  flowering  and   seed  set  is  not  a  common  event  in  Albelmoschus,  and  even  if  it  were,  the  seedlings  will  not  be   the  same  as  its  parents.  Nevertheless,  the  large  number  of  varieties  in  Papua  New  Guinea  and   other  countries  of  Melanesia  are  likely  to  be  seedlings  selected  by  farmers.  Therefore,  seed   offers  a  way  of  obtaining  healthy  plants  from  which  selections  can  be  made  for  further   propagation.   Another  cause  of  mosaic  pasterns  on  the  leaves   Note,  insects  called  jassids  also  cause  pale  green  patches  on  the  leaves  of  sliperi  kabis.  The   patches  often  occur  at  the  leaf  margins  and  between  the  main  veins  (see  Fact  Sheet  no.  39).   The  jassids  may  inject  a  toxin  into  the  leaves  as  they  feed.   In  Papua  New  Guinea,  growers  are  encouraged  to  plant  Derris  (a  shrub  common  near  the  sea,   used  as  a  fish  poison)  between  the  rows  of  cabbage  or  at  the  border  of  the  garden.  The   Kastom  Gaden  Association  is  distributing  Derris  for  farmers  to  use  on  sliperi  kabis  against  the   jassids,  as  well  as  the  flea  beetle,  Nisotra.  Fact  sheet  56c  describes  how  Derris  is  used.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Southern Leaf  Blight    

Extension Fact  Sheet  

80

Common  names:  Southern  leaf  blight,  Maydis  leaf  blight   Scientific  name:  Cochliobolus  heterostrophus;  this  is  the  name  for  the  sexual  stage;  the  asexual   stage  is  known  as  Bipolaris  maydis  (previously  it  was  Drechslera  maydis  and  Helminthosporium   maydis).   Hosts:  Maize,  including  sweet  corn,  is  the  main  host.  The  fungus  also  infects  sorghum  and   many  grasses.    

Damage The  fungus  causes  severe  damage  depending  on  the  weather  conditions,  strain,  and  the   varieties  grown.  Damage  is  worse  if  infection  occurs  before  the  silky  tufts  of  long  hairs   (stigmas)  appear,  and  temperatures  and  humidity  are  high  as  the  ears  of  maize  are  produced.     The  spots  start  on  the  lower  leaves;  at  first,  they  are  oval,  but  become  rectangular,  up  to  2.5   cm  long  and  2-­‐6  mm  wide,  confined  by  the  leaf  veins  (photo,  left).  They  are  light  brown  with  a   darker  brown  margin.  The  spots  grow  together,  so  that  large  areas  of  the  leaves  dry  up  and   die  (photo,  right).  There  is  no  information  on  the  loss  of  yield  caused  by  this  disease  in   Solomon  Islands,  but  it  is  unlikely  to  be  high,  as  the  varieties  grown  will  have  been  bred  for   resistance  to  the  disease.  In  the  1970s,  in  the  USA  and  elsewhere,  a  strain  of  the  fungus  (Race   T),  caused  an  epidemic,  and  resulted  in  ear  rot,  ear  drop  and  lodging,  and  a  large  loss  of  yield.   Race  O  is  the  common  strain  in  the  tropics  and  causes  minor  crop  loss.       The  Race  T  infects  seeds,  causing  a  dark  rot,  at  the  tip.  Infected  seedling  die  within  3-­‐4  weeks.   Race  O  is  also  seedborne,  although  the  percentage  infection  is  much  less  than  Race  T.    

AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Biology and  Life  Cycle   The  fungus  produces  large  numbers  of  spores  on  the  leaf  spots,  and  these  are  spread  by  wind   and  rain-­‐splash  between  plants.  The  disease  is  worse  on  plants  growing  under  shade,  and   when  there  are  frequent  rain  showers.       The  fungus  survives  in  seed  between  crops  (Race  T),  but  there  is  no  evidence  for  spread  in   seeds  by  Race  O.  Survival  between  crops  also  occurs  on  volunteer  maize  plants  and  grasses,   although  the  importance  of  grasses  is  not  clear.  The  fungus  survives  in  infected  crop  debris,   producing  spores,  which  are  spread  in  wind  and  rain  to  new  crops.    

Detection and  Inspection   Look  for  the  pale  brown  spots,  at  first  on  the  lower  leaves,  oval,  later  rectangular,  and  rapidly   joining  together,  destroying  the  leaves.    

Management CULTURAL  CONTROL   • • • • • •  

Grow maize  and  sweet  corn  in  the  open,  and  provide  adequate  soil  fertility  by  adding   manures  (animal  or  plant),  mulches  or  synthetic  fertilizer;     Remove  the  remains  of  maize  harvests,  and  use  to  make  compost,  rather  than  leaving   them  in  the  field  to  produce  spores  to  infect  new  crops;     If  not  removed,  then  plough  crop  remains  into  the  soil;     Remove  volunteer  maize  and/or  sweet  corn  plants;   DO  NOT  grow  maize  on  the  same  land,  one  crop  after  another;   Plant  at  wider  than  normal  spacing  to  reduce  humidity  in  the  crop.  

RESISTANT VARIETIES   Acceptable  levels  of  resistance  are  available  in  most  varieties  grown  in  the  tropics,  and  this  is   the  main  method  of  managing  the  disease.    

CHEMICAL CONTROL   Fungicides  should  only  be  considered  in  the  unlikely  event  that  resistant  varieties  are   unavailable.  Apply  when  the  lesions  first  appear,  and  repeat  if  necessary  depending  on  the   weather  conditions  during  the  growing  period.  Mancozeb  and  chlorothalonil  are   recommended.  Seed  treatments  are  not  advisable.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Bacterial Spot    

Extension Fact  Sheet  

81

Common  names:  Bacterial  spot  of  tomato  and  pepper,  Bacterial  scab,  Black  spot   Scientific  name:  Xanthomonas  vesicatoria.  Note,  it  was  called  X.  campestris  pv.  vesicatoria.   Several  strains  are  recognised,  infecting  tomato  or  pepper,  or  both.   Hosts:  Tomato  and  pepper,  and  weeds  in  the  Solanaceae  family,  for  instance,  Datura,  Physalis   (capegooseberry)  and  Nicotiana  (tobacco)  species.    

Damage Bacterial  spot  is  a  serious  disease.  It  is  especially  severe  in  wet  and  windy  conditions,  causing   plants  to  lose  their  leaves.  Damage  to  fruit  occurs  a)  when  the  disease  comes  early  as  mostly   young  fruit  are  infected;  and  b)  when  leaves  drop  exposing  the  fruit  to  the  sun.    

Biology and  Life  Cycle   The  spots  are  small,  numerous  (photo,  left),  sunken  on  the  top  leaf  surface,  and  slightly  raised   below.  Single  spots  are  up  to  3  mm;  merging,  especially  at  the  leaf  tips  and  margins,  and  leaves   look  scorched  and  turn  yellow;  sometimes  the  lower  leaves  die  and  fall.  Spots  on  the  leaf  stalks   and  stems  are  elliptical  (photo,  right).    Spots  occur  on  the  young  fruits  as  raised  scabs  (like  the   crust  that  forms  over  a  cut  or  wound  when  it  is  healing).     The  bacteria  infect  leaves  through  natural  openings;  fruit  are  infected  through  wounds,  which   may  occur  when  fruits  rub  together  or  when  bitten  by  insects.     There  are  several  ways  that  the  bacteria  spread:     • to  new  plantings  -­‐  on  infected  seed,  and  also  from  bacteria  surviving  in  the  soil  in  the   remains  of  the  last  crop;     • between  plants  -­‐  by  rain  splash,  by  overhead  irrigation,  or  by  hand  watering  when  soil  is   splashed  onto  the  leaves;  spread  is  also  by  touching  or  handling  wet  plants;   AUTHORS  Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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between crops  in  different  gardens  -­‐  in  mists  produced  by  wind-­‐blown  rain  or  irrigation   water;   on  seedlings  -­‐  infected  by  seedborne  bacteria,  or  bacteria  in  the  nursery  soil.  

Detection and  Inspection   Look  for  many  small  (2-­‐3  mm)  irregular  spots  on  the  leaves,   leaf  stalks,  stems  and  fruits.  Spots  on  the  leaf  stalks  and   stems  are  elongate,  i.e.,  longer  than  they  are  wide.  Look  for   scabby  spots  on  the  fruits  (photo,  right)  with  transparent   margins.    

Management The  control  of  bacterial  spot  relies  on  a)  growing  healthy   plants  from  seed  free  from  infection,  and  b)  care  in  handling   seedlings  when  transplanting  them  from  nursery  to  field.   Cultural  control  is  important,  as  it  is  difficult  to  control  this   disease  with  chemicals.  Not  only  are  the  chemicals  expensive,  but  also  they  are  easily  washed   off  leaves  and  fruits  in  heavy  rain  showers  that  occur  frequently  in  Solomon  Islands.    

CULTURAL CONTROL   • • • •

• • • • • • • •

Do not  plant  tomatoes  continuously:  wait  2-­‐3  years  before  growing  on  the  same  land;   Rotate  tomatoes  with  other  crops,  but  not  with  pepper  and  eggplant;   DO  NOT  use  seed  from  infected  plants;  obtain  a  new  source  –  those  sold  in  commercial   packets  from  reputable  companies  are  most  likely  to  be  free  from  infection;   If  farmers  want  to  use  their  own  seed,  first  to  avoid  passing  on  the  bacteria:    treat  the  seed   with  hot  water  at  50°C  for  25  mins,  cool  and  then  dry1.  BUT  this  should  be  done  under   supervision  by  MAL  extension  staff  using  a  thermometer  and  correctly  timed;   Make  tomato  nurseries  far  from  fields  with  tomatoes  to  prevent  infection  of  seedlings;   Carefully  inspect  every  seedling  before  taking  them  to  the  field;  remove  and  burn  any   seedlings  with  leaf  spots;   Remove  weeds  within  tomato  crops,  and  at  the  borders;  remove  self-­‐sown  tomato  plants;   Overhead  irrigation  should  be  avoided  in  favour  of  flood,  furrow  or  trickle  irrigation;  if  not   possible,  make  sure  irrigation  is  done  early  in  the  day  so  leaves  are  dry  before  evening;   If  hand  watering,  avoid  splashing  water  onto  the  leaves;     Apply  a  thick  mulch  around  the  plants  to  stop  water  splashing  bacteria  from  the  soil  onto   the  leaves;   DO  NOT  work  in  the  crop  when  plants  are  wet,  as  the  disease  can  be  spread  on  clothes;   Remove  tomato  crop  debris  after  final  harvest,  and  burn  it.  

RESISTANT VARIETIES:  There  are  resistant  varieties  of  peppers.    

CHEMICAL CONTROL   Use  copper  fungicides,  or  copper  plus  mancozeb.  It  is  very  important  to  have  healthy  seedlings   free  from  Bacterial  spot,  so  spraying  should  start  in  the  nursery,  and  continue  at  7-­‐10  day   intervals  in  the  field.  Spraying  early,  when  the  plants  are  young,  is  especially  important  as  in   wet,  windy  weather  field  sprays  alone  often  fail  to  give  adequate  control.  

1

An alternative treatment is to soak seed in 1.3% solution of sodium hypochlorite for 1 min, then rinse and dry.

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Blossom End  Rot    

Extension Fact  Sheet  

82

Common  name:  Blossom  end  rot   Scientific  name:  None.  Blossom  end  rot  is  a  “physiological”  due  to  a  lack  of  calcium.  It  is  not   caused  by  insects,  fungi,  bacteria,  or  any  other  pathogens.   Hosts:  Mostly  a  disease  of  tomato,  although  eggplant,  pepper  and  watermelon  are  also   affected.    

Damage   Symptoms  of  blossom  end  rot  first  appear  when  the  fruits  are  one-­‐third  to  one-­‐half  full  size,   and  still  green.  Not  only  are  the  fruits  unsightly,  and  they  may  have  moulds  growing  on  the   black  areas,  but  also  they  ripen  prematurely,  and  are  inedible.  They  are  neither  fit  for  the   market  or  home  use.  Losses  can  be  severe,  up  to  50%.    

Biology and  Life  Cycle   The  first  sign  of  the  disease  is  a  clear  or  light  brown  area  –  often  said  to  look  “water-­‐soaked”,   at  the  blossom  end  of  the  fruit,  which  eventually  becomes  dark  brown  or  black,  dry,  sunken   and  leathery.  Blossom  end  rot  occurs  at  any  time  when  plants  are  flowering  and  fruiting,  but  it   is  more  common  on  the  first  fruit.  Sometimes,  the  fungal  moulds  that  grow  on  the  surface  of   the  rot  after  it  has  dried  are  mistaken  for  the  cause.       Blossom  end  rot  is  caused  by  a  lack  of  calcium  in  the  plant.  This  may  mean  that  there  is  not   enough  calcium  in  the  soil,  or  that  it  is  present  but  the  roots  cannot  take  it  up.  Calcium  is   important  in  the  growth  of  cell  walls.  It  is  especially  important  in  rapidly  developing  parts  of   plants,  such  as  the  fruits.  If  there  is  not  enough  calcium,  cells  die  and  tissues  rot;  as  seen  here   in  the  fruits.   There  are  several  reasons  why  fruits  show  signs  of  blossom  end  rot.  These  are:   • calcium  in  the  soil  –  sandy  soils  lack  calcium;   AUTHORS  Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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• •

water –  if  there  is  either  too  little  water,  or  too  much,  plants  become  short  of  calcium.    For   example,  when  plants  are  grown  in  plastic  bags  or  on  raised  beds,  and  given  too  little   water,  the  soil  around  the  roots  dries  out,  then  becomes  water-­‐repellent,  and  difficult  to   wet  again;       hot  and  dry  –  if  there  is  increased  water  loss  from  the  leaves  (a  process  called   transpiration)  because  it  is  hot  and  dry,  then  plants  divert  water  containing  calcium  from   the  fruits,  and  the  fruits  suffer;   pH  –  if  the  pH  of  the  soil  is  too  low,  calcium  may  be  unavailable  by  the  roots;   nitrogen  –  too  much  nitrogen  fertilizer  makes  the  problem  worse;  this  is  because  nitrogen   stimulates  rapid  vegetative  growth  and  this  requires  calcium  for  the  cell  walls.  The  result  is   competition  between  the  demands  of  fruits  and  other  parts  of  the  plant.    

Detection and  Inspection     Look  for  black  areas  of  rot  at  the  blossom  end  of  developing  fruits,  especially  on  the  first   formed  trusses;  the  rots  might  be  covered  in  fungal  moulds.  

Management The  most  common  cause  of  blossom  end  rot  is  erratic  watering  so  that  the  plants  get  too  little   or  too  much  water.    

CULTURAL CONTROL   • •

• • • • •

DO NOT  allow  the  soil  to  dry  out;  try  to  make  sure  that  the  soil  is  moist  at  all  times,   particularly  at  the  flowering  stage;   Grow  tomatoes  in  well-­‐drained  soil  that  contains  plenty  of  organic  matter,  especially  well-­‐ rotted  manure  (but  see  use  of  chicken  manure  below);  organic  matter  holds  water,  and   also  gives  the  plants  the  nutrients  they  need,  including  calcium;   If  there  is  a  chance  that  the  plants  will  get  too  much  water,  plant  them  on  raised  bed  to   improve  soil  drainage;   Mulch  the  plants  after  transplanting  with  dried  grasses,  and  other  dried  weeds,  to  help   prevent  the  soil  from  drying  out.  The  mulch  should  be  at  least  10  cm  thick;   DO  NOT  cultivate  too  close  to  the  plants  (nor  too  deeply)  as  this  may  damage  the  roots,   and  stop  uptake  of  water  and  minerals,  including  calcium;     DO  NOT  use  urea  or  ammonium  types  of  fertilizers.  Use  of  chicken  manure  should  also  be   avoided;   Shade  plants,  or  use  windbreaks,  when  conditions  are  hot,  dry  and  windy,  and  when  the   soil  moisture  is  low.    

RESISTANT VARIETIES   Varieties  differ  in  susceptibility  to  blossom  end  rot,  with  plum  or  pear  shaped  varieties  being   the  more  susceptible.          

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Predatory Ladybeetles  

Extension Fact  Sheet  

83

Common  name:  Ladybeetles                                                                                   Scientific  name:  The  one  shown  is  Phrynocaria  sp.  There  are  many  other  ladybeetles  in   Solomon  Islands.   Prey:  Aphids,  mealybugs,  scale  insects,  caterpillar  eggs,  mites.  

Predatory  ladybeetles  are  a  farmer’s  best  friend:  they  occur  on  many  crops,  feeding  on   colonies  of  aphids,  mealybugs,  scales  and  other  damaging  insect  pests.     It  is  important  to  distinguish  predatory  or  farmer-­‐friendly  ladybeetles  from  the  plant-­‐feeding   ladybeetles  belonging  to  the  subfamily  Epilchninae  (see  Fact  Sheet  no.  58).  The  plant-­‐feeding   ladybeetles  have  short  soft  hairs  on  the  upper  surface.    

Biology and  Life  Cycle  

Eggs  are  generally  yellow  and  the  shape  of  rice  grains;  they  are  laid  on  their  ends  in  clusters,   close  to  aphid  colonies.  The  larvae  hatch  at  the  same  time,  and  look  like  miniature  crocodiles   (photo,  right).  They  have  spots  or  patches  of  dark  blue,  with  areas  of  red  or  yellow.  After   several  weeks  of  feeding  the  larva  attaches  to  a  leaf  or  a  branch,  and  turns  into  a  pupa.  The   pupa  looks  like  a  curled  up  larva,  with  similar  colours.  About  a  week  later,  the  pupa  splits  and   the  adult  crawls  out.  As  the  skin  starts  to  dry  and  harden,  the  adult  becomes  characteristically   yellowish-­‐orange  with  black  markings  (photo,  left).     The  larger  species,  feeding  on  aphids  and  insect  eggs,  are  bluish-­‐black  and  red  or  yellow;  the   smaller  species,  feeding  on  scale  insects,  are  white  with  long  waxy  threads.    

Detection and  inspection     Look  for  adults  with  bright  shiny,  round  bodies,  which  are  red  or  orange  with  black  markings  or   spots,  without  soft  short  hairs;  look  for  the  eggs,  which  are  a  creamy  yellowish-­‐orange,  laid  in   clusters  close  to  aphid  colonies;  and  look  for  the  larvae,  which  are  long,  active,  dark  with   yellow  or  red  spots  and  patches.     AUTHORS  Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Managing ladybeetles  as  biocontrol  agents     GENERAL   Ladybeetles  are  effective  biological  control  agents,  but  will  only  appear  in  the  crop  if  there  is   food  for  them,  such  as  aphids  or  scales.  Pesticides  easily  kill  them,  and  routine  spray  programs   will  destroy  any  ladybeetles  feeding  on  insect  pests  and  mites.      

(1)  MOVING  THEM  AROUND   As  all  stages  of  ladybeetles  are  relatively  large,  it  is  easy  to  move  them  to  where  they  would  do   most  good.  Handpick  adults  and  larvae,  and  pluck  leaves  with  eggs  and  pupae  and  place  them   in  a  collecting  (jam)  jar.  Transfer  the  contents  of  the  jar  onto  the  crop  plants  infested  with  pest   species.     (2)  PROVIDING  THEM  WITH  FOOD   Garden  flowers  and  weeds  provide  ladybeetles  with  sugar  from  their  nectar  or  pollen.  Planting   flowering  plants  in  the  field  and  around  the  edges  will  encourage  ladybeetles  to  stay  in  the   fields  to  breed.  Basil  and  marigolds  are  useful  garden  flowers.  Sonchus  (sow  thistles)  and   Chenapodium  (goosefoots)  are  weeds  that  are  particularly  good  sources  of  food  for   ladybeetles,  providing  nectar  and  pollen  as  well  as  aphids.      

THE DANGERS  FROM  USING  PESTICIDES   Pesticides  are  harmful  to  ladybeetles  and  should  only  be  considered  for  control  of  aphids  and   other  pests  if  ladybeetles  are  absent  or  in  low  numbers.  If  pesticides  are  needed,  use  ones  that   stay  active  on  plant  surfaces  for  a  few  days  only.  For  example,  use  Derris,  pyrethrum,  or   synthetic  pyrethroids.  These  are  destroyed  rapidly  by  sunlight.          

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Hoverflies

Extension Fact  Sheet  

84

Common  name:  Hoverflies1                                                                                   Scientific  name:  The  one  shown  below  is  probably  Ischiodon  scutellaris,  although  this  still   needs  to  be  checked.  There  are  several  species  in  Solomon  Islands.  Hoverflies  are  known  as   Syrphid  flies  or  Flower  flies,  and  belong  to  the  family  Syrphidae.   Prey:  Aphids.  

Hoverflies are  common  and  occur  in  many  crops.  They  are  important  biological  control  agents.   The  larvae  feed  on  aphids  (photo,  right),  and  these  are  their  main  food,  but  also  they  probably   eat  caterpillars,  mealybugs  and  even  other  hoverfly  larvae.       The  adults  are  typical  flies  with  one  pair  of  wings,  large  eyes  and  yellow  and  black-­‐banded   abdomens  (photo,  left).  The  adults  flies  are  often  seen  hovering  above  flowering  plants  and   sitting  on  flowers,  sucking  up  nectar.    

Biology and  Life  Cycle     The  eggs  are  small,  oval  and  white.  They  are  laid  singly  near  colonies  of  aphids,  or  even  among   them.  They  are  easily  seen  with  the  eye.  The  legless  larva  (or  maggot)  is  pale  green  at  first   becoming  darker  in  colour,  and  has  short  soft  spines  on  the  sides  (see  photo,  right).  It  narrows   towards  the  head,  where  the  mouth  is  used  to  catch  and  hold  the  aphids  before  sucking  them   dry  (photo,  right).  As  the  larva  grows  it  moults,  i.e.,  it  changes  its  skin.  When  fully  grown,  it  is   up  to  10  mm  long.  At  that  time,  it  attaches  itself  to  the  underside  of  a  leaf  and  it  swells  up  and   hardens  into  a  smooth,  teardrop-­‐shaped  puparium  (not  a  pupa  –  the  real  pupa  is  inside  the   smooth  outer  skin  of  the  last  maggot  stage).  It  is  up  to  7  mm  long.  After  a  few  days,  depending   on  the  temperature,  the  adult  hatches,  finds  flowers  with  nectar  to  feed  on,  and  then  mates.         1

Some  information  in  this  Fact  Sheet  is  taken  from  NA  Martin  (2010)  Small  hover  fly  –  Melanostoma  fasciatum.   Insect  Factsheets:  Interesting  Insects  and  other  Invertebrates.  New  Zealand  Arthropod  Collection  Factsheet  Series.   Landcare  Research.  http://nzacfactsheets.landcareresearch.co.nz/Browse.html    

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  inspection     Look  for  the  slug-­‐like  larvae  feeding  among  colonies  of  aphids.  Their  narrow  heads  are  often   seen  moving  about  as  the  larva  searches  for  food.  They  are  rarely  seen  in  populations  of   aphids  on  crops  with  hairy  leaves  such  as  tomato  and  squash.  Look  for  flies  with  yellow  and   black-­‐banded  bodies  that  hover  over  flowers,  hovering  and  then  suddenly  moving  forwards  or   sideways  only  to  hover  again.       The  adults  can  easily  be  confused  with  wasps  and  bees.  Hoverflies  bodies  are  slender  with   yellow-­‐black  wasp-­‐like  patterns  and  some  have  narrow  waists.  However,  hoverflies  lack  a   sting,  have  delicate  legs,  massive  eyes,  and  a  single  pair  of  wings  which  are  held  out  sideways   at  rest,  whereas  wasps  fold  their  wings  along  their  bodies  when  resting.  Some  types  of   hoverflies  look  like  bees,  but  the  maggots  of  these  do  not  feed  on  aphids.      

Managing hoverflies  as  biocontrol  agents    

GENERAL Hoverflies  are  very  effective  biological  control  agents,  but  only  appear  in  the  crop  if  there  are   aphids  for  them  to  eat.  Note,  pesticides  easily  kill  hoverflies,  and  routine  spray  programs  will   destroy  them.       Careful  monitoring  of  the  crop  will  help  to  determine  whether  the  hoverflies  are  present  and   are  controlling  the  aphids.  If  more  than  two  hoverfly  maggots  are  present  in  a  colony  of   aphids,  there  is  no  need  to  do  anything,  as  they  will  effectively  control  the  aphids  for  you.        

HOW TO  USE  THEM   PROVIDING  THEM  WITH  FOOD   Garden  flowers  and  weeds  provide  hoverfly  adults  with  sugar  as  nectar.  Planting  flowering   plants  in  the  field  and  around  the  edges  will  encourage  hoverflies  to  stay  and  to  breed.  Large   open  flowers,  such  as  daisies,  are  particularly  good  sources  of  food,  providing  nectar  for  the   adults.      

THE DANGERS  FROM  USING  PESTICIDES   Pesticides  are  harmful  to  hoverflies,  and  they  should  only  be  used  against  aphids  if  hoverfly   larvae  are  absent  or  in  low  numbers.  If  pesticides  are  needed,  use  ones  that  stay  active  on   plant  for  only  a  few  days.  For  example,  use  Derris,  pyrethrum,  or  synthetic  pyrethroids.  These   are  destroyed  rapidly  by  sunlight.          

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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Sunscald  

Extension Fact  Sheet  

85

Common  name:  Sunscald1   Scientific  name:  There  is  no  scientific  name.  This  is  a  “physiological”  problem.  It  is  not  caused   by  insects,  fungi,  bacteria  or  other  pathogens.     Hosts:  Capsicum,  large  red  chilli  pepper,  eggplants,  tomatoes.    

Damage   Sunscald  occurs  when  fruit  is  suddenly  exposed  to  sunlight,  especially  when  it  is  hot  and   humid.  Affected  fruits  are  unmarketable,  but  as  the  damage  is  only  on  one  side,  parts  can  still   be  used  in  the  home.  The  damage  allows  fungi  and  bacteria  to  enter  the  fruit  and  secondary   rots  may  occur.      

Biology and  Life  Cycle   Sunscald  appears  on  the  side  of  the  fruit  suddenly  exposed  to  the  sun  while  it  is  still  green.  On   capsicum,  a  white,  soft,  sunken  area  develops  that  later  dries  out  and  becomes  papery   (photo).  On  tomato,  the  damaged  area  is  white,  shiny  and  blistered,  becoming  sunken  and   wrinkled.  Symptoms  occur  on  fruits  of  any  size,  although  maturing  fruit  tend  to  be  more   susceptible  to  damage.      

1

Some information  in  this  fact  sheet  is  taken  from:  1)  Cerkauskas  R  (2004)  Sunscald.  AVRDC-­‐The  World  Vegetable   Center  Fact  Sheet.  AVRDC  Publication  04-­‐583;  and  2)  Black  LL,  Green  SK,  Hartman  GL,  Poulos  JM  (1991)  Pepper   Diseases:  A  Field  Guide.  AVRDC  Publication  No.  91-­‐347.fhm.  98pp.     AUTHORS  Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Sudden  exposure  of  the  fruits  to  sunlight  occurs  if  there  are  not  enough  leaves  to  protect  the   fruit.  This  can  occur  in  a  number  of  ways:     • • • • •

Poor leaf  development  before  flowering;   Loss  of  leaves  as  a  results  of  insect  pests  or  diseases;   Long  periods  of  wilting;   Broken  stems  and  branches  caused  by  rough  handling,  especially  when  harvesting;   Destruction  of  leaves  by  heavy  rainfall.  

Detection and  Inspection     Look  on  the  exposed  sides  of  mature  green  fruit  for  sunken  areas  that  are  white  and  papery  on   capsicum,  or  white,  shiny  patches  becoming  wrinkled  on  tomato.  Look  for  signs  of  black  fungal   growth  on  the  damaged  parts.  

Management RESISTANT  VARIETIES   No  varieties  are  resistant  to  sunscald,  but  there  are  varieties  that  have  good  foliage  cover.   Select  these  varieties  if  sunscald  cannot  be  solved  by  the  cultural  controls  suggested  below.    

CULTURAL CONTROL   • • • • •

Provide sufficient  nitrogen  for  healthy  plant  growth;   At  least  once  a  week  look  for  signs  of  insect  pests  and  diseases,  which  may  destroy  the   canopy  of  leaves  protecting  the  fruits;   Water  regularly  in  dry  weather,  to  prevent  plants  from  wilting;   Remove  flowers  at  early  stage  of  development  until  plants  are  big  enough  to  support  fruit   and  have  enough  leaves  to  provide  protection  for  the  fruit;   Support  the  plants  to  minimise  damage  due  to  wind  and  harvesting;  this  can  be  done  in  a   number  of  ways:  a)  stakes;  or  b)  string  or  wires  running  horizontally  along  the  rows.  

CHEMICAL CONTROL   Pesticides  will  not  cure  plants  that  show  symptoms  of  sunscald  as  it  is  a  physiological   condition.  However,  they  can  prevent  the  loss  of  leaves  from  insect  pests  and  diseases,  and  if   leaves  are  present  they  will  protect  the  fruits  from  sunscald.       The  choice  of  insecticide  depends  on  the  insects  that  are  present.  The  most  common  insect   pests  in  Solomon  Islands  are  Spodoptera  caterpillars  and  aphids.  For  these,  Bt  -­‐  Bacillus   thuringiensis  kurstaki  -­‐  some  plant  derived  products  (neem,  derris  and  chilli),  and  synthetic   pyrethoids  are  recommended  (see  Fact  Sheets  nos.  31  &  38).  Mites  are  also  common  on   capsicum  (see  Fact  Sheet  no.  49).  For  mites,  abamectin  (containing  a  compound  from  a  soil   bacterium)  and  synthetic  chemicals,  difocol,  sulfur  and  dimethoate  are  useful.     The  choice  of  fungicide  also  depends  on  the  type  of  disease,  with  dithiocarbamates  or  copper   products  commonly  used  for  those  causing  leaf  spots,  moulds  and  blights  (see  Fact  Sheets  nos.   45,  76  &  81).    

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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Thrips

Extension Fact  Sheet  

86

Common  name:  Thrips  are  named  after  the  plants  that  they  live  on,  e.g.,  tobacco  thrips,  onion   thrips,  flower  thrips.     Scientific  name:  The  thrips  of  Solomon  Islands  have  not  been  identified.   Hosts:  Tomato,  capsicum  and  many  other  crops.  

Damage Thrips  damage  plants  in  two  ways:  first,  they  pierce  the  cells  of  the  plants  they  feed  on  and   suck  out  the  juices;  and  second,  they  spread  viruses.  Feeding  begins  when  the   leaves  are   still   inside  the   buds  or   fruits  are   still  inside  the   flowers,  and   d amage   is  only  seen  when  they  expand.   It  may  not  be   possible  to   find  the   thrips  on  damaged  leaves  because  they  have  already  moved   to   feed  elsewhere.  As  thrips  feed,  the   cells  of  the   plant  collapse  forming  pits,  distortions  and   brown   patches  on  leaves  (photo,  lower  right),  later  with  a  sliver  sheen,  or   scaring  of  fruits   (photo,  left).  Damaged  fruits  may  not   be   suitable  for   market.  Leaves  may  dry   out   and   die   early.   In  Solomon  Islands,  it  is  not  known  if  thrips  spread  viruses.    

Biology and  Life  Cycle     Adult  thrips  are  narrow,  less  than  2  mm  long,  black  (some  species  are  yellow)  with  wings  that   have  long  hairs  at  the  margins  (photo,  right  above).  The  wings  cover  the  body  when  they  are   not  in  use.  Thrips  are  difficult  to  see  without  a  hand  lens.  The  eggs  are  bean-­‐shaped,  white,  

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   laid  on  or  inside  the  plant.  The  lifecycle  has  six  stages:  egg,  first  and  second  larva  (small,   whitish  and  very  active,  found  mainly  on  the  underside  of  the  leaf),  pre-­‐pupa,  pupa  (both   stages  occur  in  the  soil  in  natural  cracks),  and  adult.  The  pre-­‐pupa  and  pupa  are  similar  in   shape  to  the  larvae,  but  do  not  move,  feed,  and  show  the  developing  wings.       Thrips  occur  all  year  round,  but  are  particularly  active  in  hot,  dry  times  following  heavy  rains.    

Detection and  inspection     Look  on  the  underside  of  the  leaves  and  inside  flowers.  The  larvae  are  very  difficult  to  see  with   the  naked  eye,  but  with  a  hand  lens  the  long  slender,  black  bodies  of  the  adults  are  easily   recognised.  Look  for  black  or  brown  specks  where  the  thrips  feed;  these  are  faeces.  The   presence  of  faeces  is  a  way  of  telling  thrips  from  mites.      

Managing thrips      

NATURAL ENEMIES   Several  natural  enemies  feed  on  thrips.  There  are  predatory  thrips,   Minute  pirate  bugs  (photo,  right1),  predatory  mites,  lacewing  larvae   and  ladybird  beetles  (adults  and  larvae).  Note,  it  is  best  to  avoid   pesticides  to  manage  thrips,  especially  those  that  are  long  lasting,  as   they  will  destroy  populations  of  beneficial  insects.    

CULTURAL CONTROL   • • • • •  

Intercrop with  a  non-­‐host  plant  helps  to  slow  the  movement  of  thrips  through  the  crop.   For  example,  you  can  grow  peppers  between  yard  long  beans;   Rotate  crops  with  non-­‐host  plants  will  help  to  break  the  lifecycle.  Crops  commonly   attacked  by  thrips  include:  cucurbits,  crucifers,  tomatoes  and  bell  peppers;   Destroy  weeds  within  and  around  crops  to  prevent  build  up  of  thrips  populations;   Destroy  crop  remains  after  harvest  to  prevent  thrips  spreading  from  old  to  young  crops;   Use  a  hose  with  a  strong  jet  of  water  to  remove  thrips  from  the  plants.  

CHEMICAL CONTROL   It   is   unlikely  that  thrips  populations   will  be   high  enough  to  justify  pesticide  application.   In   any  case,  the  use  of   pesticides   is   likely  to   do   more  harm  than  good,  as  they  will  kill  natural   enemies.  Thrips  tend  to   hide  in   sheltered   places  on   plants  -­‐-­‐-­‐    in   leaf  and  flower  buds  or   under   the  calyx  of   the  fruit  -­‐-­‐-­‐     and  they  are  also  difficult  to   reach  with  pesticides.   If  pesticides   are   applied,  use  plant-­‐-­‐-­‐derived  products  (botanical   sprays),  and  always  try  to   treat  the   undersides   of   the  leaves.  

• • • •

Use botanical  sprays  such  as  onion,  garlic,  chilli  and  papaya  (see  Fact  Sheet  no.  56b,c);   Use  horticultural  oils  or  soap  (see  Fact  Sheet  no.  56d);   Use  neem  to  discourage  adults  from  feeding  and  laying  their  eggs  on  the  plants;   Use  synthetic  pyrethroids  (e.g.,  lambda  cyhalothrin  or  cypermethrin)  only  as  a  last  resort.  

1 Photo of Orius sp., a Minute pirate bug from http://en.wikipedia.org/wiki/Orius. It is not known if this insect is in the Solomon Islands.

AUTHORS Suzanne  Neave  •  Grahame  Jackson   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cotton Leaf  Roller  

Extension Fact  Sheet  

87

Common  name:  Cotton  leaf  roller     Scientific  name:  The  scientific  name  is  Haritalodes  derogata  (previously  Sylepta  species).   Hosts:  Sliperi  kabis  (Abelmoschus  manihiot)  and  also  okra.  In  other  countries,  this  insect  is  also   a  major  pest  of  cotton  as  the  name  suggests.  

Damage The  caterpillars  roll  the  leaves  (photo,  top  left),  remaining  inside  the  tunnel  they  create,  eating   the  leaves  at  the  edges  and  between  the  main  veins  (photo,  bottom,  right).  The  damage  to   sliperi  kabis  is  extensive  (photo,  top  right),  and  broad  leafed  varieties  (eg  “frog”)  appear  to   suffer  more  than  those  with  deeply  divided  leaves  (“noodle  hair”).  Curling,  drooping  and   defoliation  of  leaves  is  common  on  the  broad-­‐leafed  varieties.    

Biology and  Life  Cycle1  

Eggs  are  laid  singly  or  in  groups  on  the  underside  of  the  leaves.  At  first,  the  larvae  stay   together  and  feed  on  the  undersides,  only  later  staying  alone  inside  folded  leaves.  From  the   second  moult  they  have  two  dark  spots  just  behind  the  head  on  the  first  segment  of  the  thorax   (photo,  bottom  left).  After  a  short  pupal  stage,  the  adults  emerge.  Their  wings  are  cream  with   a  continuous  line  along  the  outer  and  back  border  of  the  wings,  and  dark-­‐brown  “scattered”  

1

Much of this information is from the CABI Crop Protection Compendium.

AUTHORS Grahame  Jackson  •  Suz  Neave   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   lines  elsewhere  (photo,  below).  The  wingspan  is  30-­‐40  mm.  The  life  cycle  of  the  cotton  leaf   roller,  that  is,  from  egg  to  adult  is  about  30  days.    

Detection and  inspection     Look  for  rolled  sliperi  kabis  leaves  and  typical   and  distinctive  defoliation.   Look  for   webbing   around  the  caterpillar,   which  has  two  spots   on   the  top  of   the  segment  behind  the  head.   The  spots  are  a   characteristic   feature  of  the   cotton  leaf  roller.    

Managing cotton  leaf  roller      

NATURAL ENEMIES   There  are  few  records  of  predators  and  parasites  attacking  the  cotton  leaf  roller,  except  that   spiders  and  praying  mantids  are  important  predators.  There  are  no  reports  of  any  kind  from   Solomon  Islands.      

CULTURAL CONTROL   If  only  a  few  plants  are  damaged:   • Pinch  rolled  leaves  between  finger  and  thumb,  squashing  the  caterpillar  inside;  OR   • Prune  the  rolled  leaves,  remove  the  cuttings  from  the  garden  and  burn  them.    

CHEMICAL CONTROL   It   is  best  to   test  botanical  sprays  first,  as   these  will  do   less  harm  to   natural  enemies,  and  cost   less  than  synthetic   commercial   products  which  are  also  used  to   manage  the  cotton  leaf  roller.     Plant-­‐derived  products:   • Use  botanical  sprays  such  as  onion,  garlic,  chilli  and  papaya  (see  Fact  Sheet  no.  56b,c);   • Use  horticultural  oils  or  soap  (see  Fact  Sheet  no.  56d);   • Use  neem  to  discourage  caterpillars  from  feeding,  and  adults  from  laying  their  eggs  on  the   plants  (see  Fact  Sheet  no.  56b).   “Soft”  insecticides:   • Use  Bacillus  thuringiensis,  but  note  the  following:   o Ensure  that  Bt  covers  the  plants  well;  caterpillars  will  only  die  if  they  eat  Bt;   o Eggs  are  not  susceptible  to  Bt;   o Use  Bt  as  soon  as  damage  is  seen;   o Small  larvae  are  more  susceptible  to  Bt  than  fully  grown  ones.   Synthetic  chemicals:   • Use  synthetic  pyrethroids  (e.g.,  lambda  cyhalothrin  or  cypermethrin)  only  as  a  last  resort.   avoided,  as  they  will  kill  natural  enemies;   • If  possible,  avoid  broad-­‐spectrum  insecticides  (such  as  pyrethroids  and   organophosphates),  as  they  will  kill  natural  enemies.  

AUTHORS Grahame  Jackson  •  Suz  Neave   SN  works  for  The  World  Vegetable  Center;  GJ  for  TerraCircle  Inc.  

Produced with  support  from  Integrated  crop   management  package  for  sustainable   smallholder  gardens  in  Solomon  Islands,   funded  by  ACIAR,  Canberra  

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M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Dasheen Mosaic    

Extension Fact  Sheet  

88

Common  name:  Dasheen  mosaic   Scientific  name:  Dasheen  mosaic  potyvirus  (the  abbreviation  is  DsMV).   Hosts:  Many  edible  aroids,  such  as  Alocasia  (edu),  Cyrtosperma  (kakake),  Amorphophallus   (elephant  foot  yam),  Xanthosoma  (kongkong  taro),  and  many  ornamental  aroids,  such  as   Caladium,  Dieffenbachia  and  Philodendron.  

Damage The  virus  is  common  in  taro  (photos,  top  left  &  right),  as  well  as  in  Xanthosoma  (photo,  bottom   left)  and  Alocasia  (photo,  bottom  right).  Light  streaks  appear  along  the  main  leaf  veins  or   between  them.  These  streaks  form  different  patterns:   s o m e   a r e   light  green  and  feather-­‐-­‐-­‐ like  (photo,  bottom  right);  streaking  may  appear  throughout  the  leaf  (photo,  top  left)  or  in   small  patches  (photo,  bottom  left  &  top  right).     Typically,  one  or  two  leaves  show  symptoms  followed  by  healthy-­‐looking  leaves.  Leaves  may   be  distorted,  especially  at  the  margins  (photo,  top  right).  In  general,  taro  show  more   symptoms  than  other  edible  aroids,  Alocasia,  Cyrtosperma  and  Xanthosoma.  Little  is  known   about  the  effect  of  the  virus  on  yield  of  taro  or  other  related  species.  Because  the  symptoms   are  not  severe  it  is  thought  that  the  damage  is  small.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Biology and  Life  Cycle     Aphids  (see  Fact  sheet  no.  38),  or  green  flies,  spread  DsMV.  Spread  occurs  when  winged  adults   fly  from  diseased  to  healthy  plants.  First,  the  aphids  suck  up  the  viruses  as  they  feed  on   infected  plants,  and  the  viruses  stick  to  their  mouthparts.  Second,  the  winged  adults  fly  or  are   blown  by  wind  to  healthy  plant  in  the  same  garden  or  to  other  gardens  nearby.  As  the  aphids   feed,  the  viruses  enter  the  plant.  The  viruses  do  not  multiply  inside  the  aphids,  and  they  stay   alive  on  the  aphids’  mouthparts  for  only  a  short  time.     Apart  from  being  spread  by  aphids,  DsMV  is  also  spread  in  other  ways:     • In  planting  material;  infected  plants  are  taken  to  new  gardens;   • In  sap  from  infected  plants  when  it  comes  into  contact  with  healthy  leaves;  however,  this   is  not  thought  to  be  a  common  method  of  spread;   • From  mother  plants  to  suckers.     The  virus  is  rapidly  spread  by  aphids,  and  it  is  likely  that  all  taro  are  infected  by  DsMV.  Most   plants  do  not  show  symptoms,  or  symptoms  occur  only  rarely.       Often,  there  are  signs  of  DsMV  when  plants  are  affected  by  other  virus  diseases,  alomae  (see   Fact  sheet  no.  1)  in  particular.    

Detection and  inspection     Look  for  leaves  showing  feather-­‐like  symptoms,  often  along  the  main  veins,  but  sometime   between  the  veins.  The  colour  of  the  patterns  is  yellow-­‐green  or  grey,  clearly  distinct  from  the   green  of  the  leaves.      

Managing Dasheen  mosaic  virus       Management  of  this  disease  is  likely  to  be  effective  or  necessary  for  the  following  reasons:     • Damage  due  to  DsMV  does  not  appear  to  be  serious;   • Aphids  are  common  and  will  spread  DsMV  very  quickly;   • Chemical  control  is  not  a  reliable  method  to  stop  spread  of  viruses  by  aphids.  Insecticides   can  kills  aphids.  By  the  time  the  aphids  die  they  have  already  fed  and  infected  the  healthy   plants  with  virus;     • The  virus  spreads  inside  the  plant  to  the  suckers;   • There  is  no  information  on  resistant  varieties.  Some  varieties  may  be  more  resistant  than   others,  but  tests  have  not  been  done.     Occasionally,  plants  with  severe  symptoms  do  occur.  In  these  cases,  the  entire  leaf  blade   shows  symptoms,  and  the  leaves  remain  rolled  and  perhaps  twisted,  although  they  eventually   expand.  When  plants  with  leaves  of  this  kind  are  seen,  it  is  important  to  remove  the  plant  and   destroy  it.  If  aphids  are  present,  put  a  rice  bag  over  the  plant  before  pulling  it  out,  and  then  tip   the  plant  into  a  fire  to  destroy  it  and  the  insects.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Taro Rhabdoviruses  

Extension Fact  Sheet  

89

Common  names:  There  are  no  common  names  for  these  diseases   Scientific  name:  Colocasia  bobone  rhabdovirus  (CBDV)  and  Taro  vein  chlorosis  virus  (TaVCV).   Hosts:  These  viruses  have  only  been  found  in  taro.  CBDV  occurs  in  “male”  taro,  which  are  the   common  types  in  Solomon  Islands.  It  is  the  same  virus  that  causes  Bobone  in  “female”  taro   (see  Fact  sheet  no.  1).    

Damage Little  is  known  about  the  impact  of  these  viruses  on  the  yield  or  other  characteristics  of  taro.   Usually,  only  one  or  two  leaves  are  affected  before  healthy-­‐looking  leaves  develop,  so  it  is   likely  that  the  impact  is  small.  The  main  concern  is  that  these  viruses  might  be  involved  in  the   disease  of  taro  known  as  alomae.     Although  these  viruses  belong  to  the  same  virus  group  (ie  they  are  both  rhabdoviruses),  the   symptoms  they  cause  in  taro  are  different.  CBDV  causes  deformed,  thickened  veins  in  patches   which  are  often  slightly  darker  than  the  surrounding  areas.  By  contract,  TaVCV  causes  a   yellowing  or  chlorosis  of  the  smaller  veins  either  side  of  the  main  ones  (photo,  bottom  left).   The  yellowing  produces  a  feather-­‐like  pattern  (photo,  bottom  right);  this  is  similar  to  that   caused  by  Dasheen  mosaic  virus  (see  Fact  sheet  no.  88),  but  in  the  case  of  TaVCV,  the   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   yellowing  is  much  brighter.  Also,  as  the  leaf  ages  the  yellow  lines  start  to  die  and  they  turn   brown,  as  can  be  seen  above  (photo,  bottom  right),  in  the  lower  left  part  of  the  leaf.    

Biology and  Life  Cycle     The  name  “rhabdo”  for  these  viruses  means  rod,  referring  to  the  shape  of  the  virus  particle   (photo,  below).  In  the  photo,  the  virus  particles  can  be  seen  lengthways  and  end  on.       CBDV.  This  virus  causes  different  symptoms  depending  on   the  variety  of  taro.  In  most  varieties  (called  “male”  taro)  it   causes  the  symptoms  seen  above  (photos,  top).  In  “female”   taro  the  virus  causes  bobone  (see  Fact  Sheet  no.  1).  Where   this  virus  occurs  with  other  viruses  plants  develop  alomae,   and  die.     TaVCV.  Symptoms  of  this  virus  are  seen  in  both  “male”  and   “female”  taro.  Symptoms  of  TaVCV  may  occur  on  plants   with  bobone  and  also  with  alomae,  but  it  is  not  known  if   this  virus  is  involved  in  either  of  these  diseases.     Spread  of  CBDV  is  by  planthoppers,  Tarophagus  species.  No  tests  have  been  done  to  confirm   that  TaVCV  is  spread  by  planthoppers,  though  this  is  assumed  it  is  similar  to  CBDV.  The   planthoppers  suck  up  the  viruses  when  they  feed  on  sap.  The  viruses  multiply,  and  after  3-­‐4   weeks  the  planthoppers  are  able  to  spread  the  viruses  as  they  feed.  The  viruses  are  unlikely  to   be  spread  in  plant  sap  alone.     CBDV  and  TaVCV  are  also  spread  in  other  ways:     • From  mother  plants  to  suckers;   • In  planting  material  when  infected  plants  are  taken  to  new  gardens;    

Detection and  inspection     Look  for  leaves  showing  irregular,  thickened  patches  which  are  dark  green  (CBDV).  Look  for   leaves  showing  bright  yellow,  feather-­‐like  symptoms  along  the  main  veins  (TaVCV).  Look  to  see   if  plants  produce  healthy  leaves  after  one  or  two  with  symptoms.    

Managment   These  viruses  are  unimportant  alone,  but  it  is  their  association  with  alomae  and  bobone  that  is   of  concern.  Knowing  what  causes  alomae  would  help  to  give  useful  recommendations.       • Do  not  grow  “male”  and  “female”  taro  in  the  same  garden;  bobone  is  likely  to  be  caused   by  CBDV,  and  that  virus  is  involved  with  others  in  alomae;   • If  symptoms  of  CBDV  and  TaVCV  are  seen,  mark  plants  with  a  stake;  at  harvest  cut  off  the   corms,  sell  or  eat  them,  and  burn  the  plant  and  suckers  –  DO  NOT  REPLANT;   • If  alomae  occurs,  remove  the  plants  and/or  use  chemicals  to  kill  the  planthoppers  (see   Fact  sheet  no.  1).      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Coconut Leaf  Spots  

Extension Fact  Sheet  

90

Common  name:  Brown  leaf  spot  and  Grey  leaf  spot   Scientific  names:  Pseudoepicoccum  cocos  (Brown  leaf  spot);  Pestalotiopsis  palmarum1  (Grey   leaf  spot).   Host:  Coconut,  other  palms,  including  betel  nut  and  oil  palm.    

Damage Both  these  fungal  diseases  are  more  severe  on  older  leaves.  Neither  disease  is  likely  to  affect   yields  of  nuts.     Brown  leaf  spot  (photo,  left):  The  disease  affects  all  varieties  of  coconuts,  usually  on  the  older   leaves.  Young  plants  of  Malayan  Dwarfs  and  its  hybrids  are  said  to  be  more  affected  than  other   varieties  (in  Samoa),  especially  when  these  are  grown  in  high  rainfall  areas.  These  diseases   have  not  been  studied  in  Solomon  Islands.       Grey  leaf  spot  (photo,  right):  This  disease  causes  a  blight  of  coconuts  and  related  palms.  When   older  leaves  are  severely  blighted  this  indicates  unfavourable  growing  conditions.    

Biology and  Life  Cycle   Brown  leaf  spot:  Oval  spots  develop  on  the  upper  surface  of  older  leaves,  up  to  10  mm  long   and  4  mm  wide,  with  grey  centres  surrounded  by  relatively  wide  dark  brown  margins.  On  the   1

The  photographs  are  used  with  the  kind  permission  of  Eric  McKenzie,  Landcare  Research,  Auckland,  New  Zealand.  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   lower  surface,  the  margins  of  the  spots  are  less  distinct,  but  it  is  here  that  black  powdery  spore   masses  develop.  The  spores  are  very  small  and  round,  and  can  only  be  seen  with  a  microscope.     Grey  leaf  spot:  The  spots  are  up  to  15  mm  long,  slightly  larger  than  those  of  brown  leaf  spot,   grey  with  a  thin  dark  brown  border.  Sometimes  the  spots  join  together  and  are  surrounded  by   yellow  haloes.  Fungal  fruiting  structures  are  visible  as  tiny  black  dots  within  the  spots,   especially  on  the  upper  surface  of  the  leaves.     Rain  and  wind  spread  the  spores  of  both  these  leaf  spot  fungi,  so  the  diseases  are  more   common  during  wet  weather.  

Detection and  Inspection   Look  for  the  numerous  oval  leaf  spots  10-­‐15  mm  long  on  older  leaves;  distinguish  between  the   two  diseases  by  looking  for  spots  with  small  grey  centres  and  wide  brown  borders  of  Brown   leaf  spot,  compared  with  large  grey  spots  and  thin  brown  borders  of  Grey  leaf  spot.  Look  for   the  spore  masses  on  the  underside  of  leaves  of  Brown  leaf  spot,  and  fruiting  bodies  in  spots  on   the  upper  surface  of  leaves  of  Grey  leaf  spot.  

Management CULTURAL  CONTROL   The  diseases  occur  on  older  leaves  and  are  unlikely  to  reduce  yields.  Occasionally,  severe   during  long  periods  of  wet  weather,  and/or  where  palms  are  growing  in  nutritionally  poor  soil.   If  control  measures  are  warranted,  improve  nutrition  and  growing  conditions.  If  spots  occur  in   nurseries,  and  these  are  under  shade,  decrease  shade  levels.    

RESISTANT VARIETIES   Malayan  Dwarf  and  its  hybrids  may  be  more  susceptible  to  Brown  leaf  spot,  but  no  studies   have  been  carried  out  in  Solomon  Islands.  

CHEMICAL CONTROL   Chlorothalonil,   copper  oxychloride   or  mancozeb  are  effective  against  the  fungi  causing   these  leaf  spots.  However,  fungicides   are  unlikely  to  have  a  major  impact  given  the  minor   damage  caused  by  these  diseases,  and  their  use  is  therefore  not  recommended  

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Citrus Canker  

Extension Fact  Sheet  

91

Common  name:  Citrus  canker   Scientific  names:  Xanthomonas  citri  pv.  citri;  previously  its  name  was  X.  axonopodis  pv.  citri.   There  are  several  strains  of  the  bacterium.   Hosts:  All  varieties  of  citrus  are  susceptible,  including  grapefruit,  kumquat,  lemon,  lime,   mandarin,  orange,  pummelo  and  tangerine,  as  well  as  other  genera  in  the  citrus  family   (Rutaceae),  eg  Fortunella  and  Poncirus.      

Damage   This  is  a  bacterial  disease  producing  spots  on  leaves,  fruits  and  twigs.  Where  storms  are   common,  leaves  fall  early  and  fruit  drop  before  it  is  mature.     Brown  raised  spots  –  described  as  craters  or  blisters  -­‐  occur  on  the  leaves  (photo)  surrounded   by  yellow  margins.  The  spots  are  up  to  10  mm  diam.,  depending  on  time  of  infection  and   variety.  They  occur  on  both  sides  of  the  leaves.  The  centres  of  older  spots  may  fall  out  (photo,   upper  right).  Similar  spots  occur  on  the  leaf  stalks  and  twigs  and  these  develop  into  cankers,   causing  stem  or  branch  dieback.  The  craters  or  blisters  on  the  fruit  do  not  have  yellow  margins.     The  spots  or  blisters  can  be  confused  with  Citrus  scab,  a  disease  caused  by  a  fungus  (see  Fact   Sheet  no.  48).  However,  leaves  infected  by  canker  are  not  misshapen.  

Biology and  Life  Cycle   The  disease  is  common  in  countries  where  it  is  hot  with  high  rainfall.  Infection  occurs  on  young   leaf  flushes,  stems  and  fruit;  it  declines  as  fewer  new  leaves  are  formed  and  fruits  develop.     Short-­‐distance  spread  occurs  when  water  flows  over  the  spots,  bacteria  ooze  out  and  are   spread  by  wind-­‐driven  rain  and  water-­‐splash.  The  bacteria  enter  the  leaves  through  natural   openings  –  helped  by  winds  of  more  than  30  kph  -­‐  and  wounds,  especially  those  made  by   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   leafminers.  Pruning  can  also  cause  wounds  which  are  entry  points  for  the  bacteria.     Spread  over  long  distances  occurs  during  cyclones  and  on  nursery  plants.  Strong  winds  not   only  spread  the  bacteria,  but  also  damage  the  trees  and  force  the  bacteria  into  natural   openings  and  wounds.  Spread  can  also  occur  on  tools  and  other  farm  equipment;  and  it  is  also   spread  on  people,  birds  and  insects.   The  bacteria  survive  in  the  raised  spots  on  leaves  and  fruit  until  they  fall,  and  then  for  a  few   months  in  leaf  litter  in  the  soil.  They  can  also  survive  on  weeds,  some  of  which  are  infected.    

Detection and  Inspection   Look  for  the  raised  spots,  light  brown  at  first,  gradually  darkening  and  forming  a  crater,  on   leaves,  stems  and  fruit.  Hold  the  leaves  to  the  light,  and  look  for  a  water-­‐soaked  margin  to  the   spot,  surrounded  by  a  bright  yellow  ring.  Check  that  the  leaves  are  not  distorted  or  misshapen.  

Management QUARANTINE   Canker  is  a  disease  of  quarantine  importance:  countries  free  from  the  disease  regulate  the   importation  of  citrus  propagating  material  and  fruit  from  those  that  have  it.  In  Solomon   Islands,  it  has  only  been  recorded  on  Guadalcanal.  Surveys  are  needed  in  other  provinces  to   prevent  and  contain  spread.  

CULTURAL CONTROL   There  are  a  number  of  ways  to  reduce  infection  of  canker  where  the  disease  is  endemic,  ie   where  it  is  well  established  and  outbreaks  occur  regularly.     • Canker-­‐free  nurseries.  This  is  an  important  part  of  the  management  of  the  disease;   • Do  not  work  in  infected  orchards  when  the  foliage  is  wet  from  dew  and  rain;   • Windbreaks.  Plant  trees  around  blocks  and/or  between  rows  of  large  citrus  plantations.  A   10  m  tall  windbreak  is  effective  for  about  100  m.  The  distance  between  windbreaks   depends  on  the  susceptibility  of  the  variety.  

RESISTANT VARIETIES   Grapefruit,  Mexican  lime  and  trifoliate  orange  are  highly  susceptible  to  canker.  Sour  orange,   sweet  orange,  lemon  and  lime  are  moderately  susceptible,  and  mandarin  moderately   resistant.  Preference  should  be  given  to  Valencia  orange  and  mandarin.  

CHEMICAL CONTROL   Copper  fungicides  are  effective  in  preventing  fruit  infection,  but  less  so  for  leaf  infection   because  leaves  rapidly  expand,  exposing  surfaces  without  copper  protection.  Apply  two  or   three  sprays  3  weeks  apart,  beginning  when  the  fruits  are  about  5  mm  diam.  The  important   time  is  the  90  days  after  petal  fall,  when  fruits  are  susceptible.     Where  leafminers  are  a  problem,  use  a  petroleum  oil  on  flushes  of  foliage.  Leafminers  do  not   spread  canker,  but  damage  the  leaf  increasing  the  number  of  infections.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Frog-­‐eye Leaf  Spot  

Extension Fact  Sheet  

92

Common  names:  Frog-­‐eye  leaf  spot;  Stem-­‐end  rot   Scientific  name:  Cercospora  capsici.   Hosts:  Capsicum  (bell  pepper),  Capsicum  annuum,  and  chilli,  C.  frutescens.    

Damage A  fungus  causes  the  damage.  In  wet  weather,  the  disease  causes  loss  of  leaves  (photo,  left),   and  lower  fruit  production.  In  severe  cases,  a  stem-­‐end  rot  affects  the  fruits.    

Biology and  Life  Cycle   The  spots  on  the  leaves  are  distinctive.  They  are  brown,  up  to  10  mm  diam.,  and  have  a  0.5-­‐1   mm  whitish  or  grey  centre,  hence  the  name  frog-­‐eye.  As  the  spots  develop,  surrounding  areas   of  the  leaf  start  to  turn  yellow  (photo,  right).  In  severe  cases,  the  spots  merge  so  that  large   areas  of  the  leaves  are  diseased.  Even  a  few  spots  on  a  leaf  may  result  in  early  leaf  fall.       The  spores  of  the  fungus  are  spread  by  wind  and  rain.    

Detection and  Inspection   Look  for  brown  roughly  circular  spots  with  whitish  centres.  

Management CULTURAL  CONTROL  

• •

Do not  plant  one  crop  of  capsicum  or  chilli  after  another  on  the  same  land.  Do  not  plant   susceptible  crops  for  at  least  3  years  after  the  disease  has  occurred.       The  fungus  is  seed  borne.  Make  sure  fruits  selected  for  seed  do  not  have  stem-­‐end  rots.      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   RESISTANT  VARIETIES  

None known.   CHEMICAL  CONTROL  

The warm  wet  conditions  in  Solomon  Islands  favours  the  disease,  and  fungicides  may  be   needed  to  give  adequate  control.  Use  chlorothalonil  (Bravo),  copper  oxychloride  or  mancozeb.   Treatment  should  start  when  the  spots  first  appear,  and  continue  at  10-­‐14  days  intervals  until   3-­‐4  weeks  before  last  harvest.  It  is  important  to  spray  both  sides  of  the  leaves.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Yam Scale  

Extension Fact  Sheet  

93

Common  names:  Yam  scale;  Turmeric  root  scale   Scientific  name:  Aspidiella  hartii.   Hosts:  Yams,  especially  kai  and  pana,  ginger,  taro,  turmeric,  and  other  plants.    

Damage The  scale  insects  do  the  damage  stored  yams.  Large  numbers  (photo,  right1)  turn  the  yams  a   light  grey  (photo,  left).  The  scales  have  long  tube-­‐like  mouthparts  that  pierce  the  skin  of  the  yam   tubers  and  feed  on  the  flesh  beneath.  When  many  insects  are  present,  their  feeding  dries  the   tissues,  which  then  become  fibrous.  Biology  and  Life  Cycle   This  species  of  scale  is  called  an  armoured   scale  because  it  produces  a  hard  covering   over  its  body.  The  scale  has  males  and   females,  and  it  lays  eggs.     Armoured  scales  do  not  produce  honey  dew   that  favours  the  growth  of  sooty  mould  on   the  leaves  below  (see  Fact  Sheet  no.    51).     The  life  cycle  of  A.  hartii  is  shown  in  the   diagram  on  the  right2.  The  crawlers  are  the  active  stage,  walking  or  blown  by  wind  to  new  hosts.   Once  the  female  settles  down  to  feed,  it  secretes  the  round  (1-­‐2.5  mm  diam.),  brownish  to   brownish-­‐grey,  waxy  covering  over  its  body  –  the  armour.  The  scale  lives  beneath  it,  feeding  and   1 2

Kindly provided by Georg Goergen, International Institute of Tropical Agriculture, Benin With kind permission of Gillian Watson, California Department of Food and Agriculture, Sacramento

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   breeding.  The  second-­‐stage  male  also  settles  down  to  feed  and  develops  a  scale  cover,  which  is   similar  to  that  of  the  female  but  is  rounder  and  slightly  smaller.  However,  it  goes  through  a  resting   stage,  a  pupa,  and  hatches  as  a  tiny  mosquito-­‐like  insect,  with  wings.  It  has  no  mouthparts  so   cannot  feed.  It  lives  for  only  a  few  hours  or  a  few  days.  

Detection and  Inspection   Look  for  yams  that  have  a  light  brown  to  grey  appearance  in  storage.  Use  a  hand  lens  to  look   for  the  scales,  less  than  1  mm  diam.  They  cannot  be  seen  clearly  with  the  naked  eye.    

Management CULTURAL  CONTROL   • • •

Check the  surface  of  yams  before  they  are  stored.  If  scales  are  seen,  refer  to  the  chemical   control  section  below;   Inspect  yams  in  storage  regularly,  and  remove  those  that  become  infested  with  the  scale.   Use  for  food,  or  refer  to  the  chemical  control  section  below;   Select  tubers  that  are  free  of  scale  insects  for  planting.  

RESISTANT VARIETIES   None  known.  

CHEMICAL CONTROL   Use  horticultural  oil  or  soap  solution  on  yams  infested  with  scale:  a)  after  harvest  and  before   yams  are  placed  in  storage;  b)  during  storage  on  yams  where  infestations  begin;  and  c)  at  the   time  of  planting  before  the  tubers  are  cut  (see  Fact  Sheet  no.  56d).       Horticultural  oil:   • 3  tablespoons  (1/3  cup)  cooking  oil  in  4  litres  water   • ½  teaspoon  detergent  soap   • Shake  well  and  use     Soap:     • Use  soap  (pure  soap,  not  detergent)   • 5  tablespoons  of  soap  in  4  litres  water;  OR   • 2  tablespoons  of  dish  washing  liquid  in  4  litres  water      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Taro Leaf  Spots  

Extension Fact  Sheet  

94

Common  names:  Brown  (Ghost  spot),  Orange,  White  leaf  spots  and  Shot-­‐hole   Scientific  names:  Cladosporium  colocasiae,  Neojohnstonia  colocasiae,  Pseudocercospora   colocasiae,  Phoma  sp.  (respectively).   Host:  Taro.    

Damage Four  fungi  cause  these  leaf  spots.  They  are  mostly  found  on  the  older  leaves,  and  are  unlikely   to  affect  corm  yields,  though  further  studies  are  needed  to  confirm  this.  Leaf  spot  symptoms   associated  with  the  four  fungi  are  similar,  except  for  Shot-­‐hole.     Brown  or  Ghost  leaf  spot  –  Spots  yellow  at  first  (photo,  top  left),  later  reddish  brown  spots  and   blotches  with  light  brown  centres,  round  or  irregular  up  to  15  mm  diam.  There  are  fewer  spots   on  the  under  surface  of  leaves  because  not  all  spots  penetrate  the  leaf,  hence  the  name  Ghost   spot.  Spots  may  merge  causing  leaves  to  dry  out  at  the  margins  (photo,  bottom  left).     Orange  leaf  spot  –  Yellow-­‐brown,  round  or  irregular  spots,  up  to  15  mm  diam.,  on  both  sides   of  the  leaf  (photos,  centre  top  &  bottom).  Sometimes  spots  have  a  yellow  margin.  Spots   become  darker  on  the  lower  surface  as  spores  develop.       White  leaf  spot  -­‐  On  the  upper  surface  spots  are  whitish-­‐green,  up  to  15  mm  diam.  (photo,  top   right);  on  the  lower  surface  spots  have  dark  centres  as  spores  develop,  leaving  a  whitish   margin.       AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   Shot-­‐hole  –  Brown  spots,  enlarging  to  20  mm,  round  oval  or  irregular,  distinctive  as  the  centres   fall  out  (photo,  bottom  right).  Often  the  holes  have  a  bright  yellow  margin.  Some  spots  merge   forming  larger  shot-­‐holes.                                 These  leaf  spots  are  found  in  the  coastal  areas  as  well  as  in  the  highlands.  They  are  especially   common  where  rainfall  is  high.  

Biology and  Life  Cycle   The  fungi  are  spread  by  wind,  rain-­‐splash,  and  wind-­‐blown  rain.  The  diseases  are  found  in  the   coastal  areas,  but  Brown  leaf  spot  and  Shot-­‐hole  also  occur  in  the  cooler  mountainous  regions.   Shot-­‐hole  is  worse  in  cooler  areas.  

Detection and  Inspection   Look  for  spots  with  diffuse  margins,  lacking  a  clear  line  between  diseased  and  healthy  areas  of   the  leaf.  Look  for  spots  that  are  present  on  the  top  of  the  leaf  but  not  penetrating  to  the   underside.  Look  for  spots  with  dark  velvety  centres  where  the  spores  form,  more  noticeable   on  the  under  surface  of  the  leaves.  It  is  difficult  to  tell  the  difference  between  Brown,  Orange   and  White  leaf  spots  in  the  field;  a  microscope  is  needed  to  confirm  the  diseases  by  looking  at   their  spores.  Look  for  spots  where  the  centres  have  fallen  out.  

Management Although  these  diseases  are  common,  they  are  not  a  threat  to  taro  production;  they  mostly   affect  older  leaves  causing  them  to  die  earlier  than  they  would  if  they  were  healthy;  they  do   not  reduce  the  number  of  leaves  to  the  extent  that  this  affects  yield.  

RESISTANT VARIETIES   Different  varieties  are  said  to  exhibit  different  susceptibilties  to  the  four  leaf  spot  diseases,   particularly  for  Shot-­‐-­‐-­‐hole.  

CHEMICAL CONTROL   As  these  diseases  cause  little  economic  loss,  fungicides  are  not  recommended.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cassava Brown  Leaf  Spot    

Extension Fact  Sheet  

95

Common  name:  Brown  leaf  spot   Scientific  names:  Cercosporidium  henningsii;  Cercospora  henningsii.   Host:  Cassava.    

Damage

A fungus  causes  the  leaf  spots.  The  disease  usually  occurs  on  the  older,  lower  leaves,  and  is   more  noticeable  5-­‐6  months  after  planting.  Leaves  fall  prematurely.   Leaf  spots  are  circular,  up  to  15  mm  diameter,  becoming  angular  and  limited  by  veins  (photo1).   The  spots  are  brown  on  upper  surfaces  with  dark  borders,  sometimes  surrounded  by  indistinct   yellow  margins.  On  the  underside,  the  spots  are  grey  with  less  distinct  borders.  Minor  veins   crossing  the  spots  appear  as  black  necrotic  lines.  The  centres  of  the  spots  dry,  crack  and  may   fall  out.  As  the  spots  enlarge,  the  leaves  yellow  and  fall  off.    

Biology and  Life  Cycle   Warm,  humid  weather  increases  the  severity  of  the  disease.  Spores  of  the  fungus,  produced  on   the  lower  surface,  are  spread  by  wind  and  water-­‐splash.  Long  distance  spread  occurs  when   spores  are  carried  on  planting  material.  In  general,  older  leaves  are  more  susceptible  to  the   disease.   The  fungus  can  continue  to  live  on  old  fallen  leaves.    

Detection and  Inspection   Look  for  round  spots  with  yellow  margins  on  the  older  leaves.    

Management Losses  of  up  to  30  per  cent  of  the  yield  of  roots  have  been  reported  from  Africa;  up  to  23  per   cent  in  South  America,  and  17  per  cent  in  India.  However,  serious  defoliation  requiring  disease   1

The photo is used with kind permission of Eric McKenzie, Landcare Limited, New Zealand.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   control  has  not  been  reported  in  Pacific  Island  countries.  If  control  is  required,  reduce  plant   density  (ie  increase  the  spacing  between  plants)  to  lower  the  humidity  within  the  plantation.   CULTURAL  CONTROL  

• • • •

Plant at  wide  spacing;   During  the  dry  season  badly  diseased  leaves  can  be  removed  to  prevent  the  disease   spreading  quickly  when  the  rains  start;   Crop  rotations  of  3  to  5  years;   Planting  in  the  wet  season,  so  that  crops  are  in  the  susceptible  stage  (6-­‐8  months  old)  in   the  dry  season.  

RESISTANT VARIETIES   Varieties  are  said  to  differ  in  resistant  in  other  countries,  but  nothing  is  known  about  this  in   Solomon  Islands.  Check  if  there  are  differences  in  the  amount  of  leaf  loss,  and  choose  those   with  the  least  damage.  

CHEMICAL CONTROL   For  chemical  control,  if  warranted,  copper  fungicides.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Sweetpotato Flea  Beetle    

Extension Fact  Sheet  

96

Common  name:  Sweetpotato  flea  beetle   Scientific  name:  Chaetocnema  sp.    In  the  USA,  the  Sweetpotato  flea  beetle  is  C.  confinis.   Hosts:  Sweetpotato,  most  probably  water  spinach  (kangkong),  and  wild  Ipomoea  species  in  the   Convolvulaceae  family,  of  which  there  are  many  in  Solomon  Islands.    

Damage A  small  beetle  does  the  damage.  The  beetles  (photo,  right1  &  arrowed  left)  are  about  1.5  mm   long.  They  feed  on  the  top  of  the  leaves,  scraping  off  the  surface  and  creating  light  green,   pencil  thin,  irregular  feeding  marks  (photo,  left).     It  is  unlikely  that  the  damage  caused  when  the  beetle  feeds  on  the  leaves  affects  the  yield  of   sweetpotato  roots.  Sweetpotatoes  can  lose  about  one  third  of  their  leaves  before  yields  are   affected.  However,  there  has  been  no  assessment  of  the  damage  done  to  the  feeding  roots   when  populations  of  the  beetle  are  high.  

Biology and  Life  Cycle   The  Sweetpotato  flea  beetle  has  not  been  studies  in  Solomon  Islands,  so  this  account  is   adapted  from  the  life  history  of  other  species.  The  females  lay  eggs  in  the  soil  at  the  base  of   sweetpotato  or  other  plants  that  are  hosts.  The  eggs  hatch  in  7  to  14  days,  and  the  larvae,   small  white  worm-­‐like  bodies,  feed  on  the  roots.  In  some  species  this  causes  serious  damage.   Afterwards,  the  larvae  develop  into  pupae,  and  about  a  week  later,  into  adults.    

Detection and  Inspection   Look  for  the  feeding  marks  on  the  top  surface  of  the  leaf:  they  are  very  distinctive.  

1

By kind permission of the Mississippi Entomological Museum, Mississippi State University.

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management CULTURAL  CONTROL  

• •

Select vines  from  plants  without  the  feeding  marks,  ensuring  that  the  cuttings  do  not   contain  adult  beetles;   Do  not  replant  sweetpotatoes  in  the  same  plots  where  beetle  damaged  occurred  in  the   previous  crop,  plant  them  as  far  away  as  possible.  

RESISTANT VARIETIES   No  resistant  varieties  are  known.    

CHEMICAL CONTROL   No  pesticides  are  recommended  because  the  damage  caused  by  the  beetle  is  unlikely  to   affects  root  yields.            

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Yam Rust    

Extension Fact  Sheet  

97

Common  name:  Yam  rust   Scientific  name:  Goplana  dioscorea.     Hosts:  Yam  species,  Dioscorea  alata  (kai),  and  D.  bulbifera  (bitter  yam  or  air  potato).    

Damage A  fungus  causes  the  disease.  Yellow  spots  or  pustules  (photo)  develop  on  the  upper  leaf   surface  (rarely  on  the  lower  leaf  surface),  and  sometimes  on  the  petioles  and  stems.  This  is  a   minor  disease  in  Solomon  Islands,  and  it  is  unlikely  to  affect  tuber  yields.  It  occurs  late  and  the   damage  is  relatively  small.       In  recent  years  severe  outbreaks  of  this  disease  have  occurred  in  Pohnpei,  Federated  States  of   Micronesia,  so  it  is  important  to  be  on  the  look  out  to  see  if  symptoms  have  changed  in   Solomon  Islands.       Biology  and  Life  Cycle   The  deep-­‐seated  leaf  pustules  are  scattered  or  loosely  grouped  in  areas  up  to  10  mm  diam.   Initially,  a  raised  layer  of  dark  brown  to  blackish  host  tissue  covers  the  pustules,  but  this   ruptures  to  expose  the  yellow  spores  which  are  then  spread  in  the  wind.  

    AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Detection and  Inspection     Look  for  the  yellow  to  light  orange  pustules  on  the  leaf,  more  obvious  on  the  upper  surface,   sometimes  present  on  the  leaf  stalks  and  stems.    

Management The disease is usually of only minor importance and controls are not generally needed.

QUARANTINE It  is  important  to  note  that  in  the  2000  to  2001  yam  season  in  Pohnpei,  Federated  States  of   Micronesia,  there  was  a  widespread  epidemic  of  yam  rust.  The  rust  had  been  recorded  in   Pohnpei  previously,  but  was  not  known  to  be  a  serious  disease.  During  the  epidemic,  more   than  80  per  cent  of  the  plants  were  affected  in  some  areas.       However,  it  was  not  entirely  clear  if  the  disease  referred  to  as  severe  leaf  blight,  with  stem   dieback,  was  due  to  the  rust  alone.  It  was  possible  that  another  fungus  was  present.  The   description  of  symptoms  and  photos  resembled  those  caused  by  the  yam  anthracnose,   Colletotrichum  gloeosporioides  (see  Fact  Sheet  no.  16).       Nevertheless,  the  symptoms  of  rust  were  more  severe  than  described  previously,  either  in   Pohnpei  or  elsewhere  in  the  Pacific.  The  presence  of  pustules  on  the  stems  was  particularly   noticeable,  and  unusual.  The  presence  of  these  pustule  caused  speculation  that  a  new  race   might  be  involved.  If  true,  this  has  quarantine  implications  for  the  movement  of  planting   material  between  countries.        

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Green Vegetable  Bug    

Extension Fact  Sheet  

98

Common  names:  Green  vegetable  bug;  Green  stink  bug;  Green  shield  bug;  Southern  green   stink  bug   Scientific  name:  Nezara  viridula.   Hosts:  Commonly  on  brassicas,  cucurbits  and  legumes,  including  Yard  long  beans  in  Solomon   Islands.  Many  other  plants  are  attacked.    

Damage  

The damage  is  done  by  a  large  sucking  bug  (photo,  left1),  which  is  common  in  Solomon  Islands   and  throughout  the  world.  It  is  a  major  pest.  The  bugs  have  needle-­‐like  mouthparts  and  use   them  to  feed  on  developing  flowers,  fruits  and  seeds.  The  punctures  produce  brown  or  black   spots.  On  Yard  long  bean,  for  instance,  the  bugs  suck  the  seeds  and  the  pods  become   misshapen  and  shrivelled.  On  tomatoes,  fruits  mature  early  and  fruit  size  and  weights  is   reduced.       Much  of  the  damage  caused  by  this  pest  is  due  to  the  reduction  in  seed  germination.     Feeding  punctures  of  the  Green  vegetable  bug  also  cause  indirect  damage.  The  punctures   allow  the  entry  of  fungi  and  bacteria  that  cause  secondary  spots  and  rots.       Studies  done  in  other  countries  on  cowpeas,  a  close  relative  of  Yard  long  bean,  showed  that   damage  to  seeds  can  be  high  even  with  relatively  few  bugs,  about  12  per  metre  of  row.    

1

By  kind  permission  of  Cameron  Prybol,  Department  of  Biochemistry  and  Molecular  Biology,  The  University  of   Georgia,  USA.     AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Biology and  Life  Cycle   Eggs,  cream  to  yellow  at  first,  are  laid  in  batches  of  50  to  100  on  the  undersides  of  leaves;  later   they  become  bright  orange.  The  nymphs  are  at  first  black  and  stay  together,  but  as  they  grow   and  moult  (there  are  five  nymph  stages)  more  of  their  bodies  become  green  (photo,  right  –  5th   stage  nymph),  and  the  bugs  stay  alone.  When  adult  they  are  about  15  mm  long  and  8  mm   wide.  The  lifecycle  takes  about  35  days  to  complete  in  the  tropics.  There  is  no  information   from  Solomon  Islands  about  the  host  plants  that  the  bug  breeds  on.  In  other  countries,   soybean,  thistles  and  rice  are  major  hosts.     The  bugs  are  strong  flyers  and  will  fly  away  when  disturbed.  Also,  when  disturbed  they  release   a  strong  foul  smell,  hence  the  name  “stink  bug”.      

Detection and  Inspection   Look  for  a  large  green  bug  with  long  needle-­‐like  mouthparts  often  feeding  on  the  seeds  of  Yard   long  beans  and  other  seed  legumes.  Look  for  the  bugs  early  in  the  day  when  they  bask  in  the   sun;  later,  at  midday,  they  retreat  into  the  canopy.  There  is  a  good  video  on  sampling  using  a   beat  sheet  at:  http://www.youtube.com/watch?v=56OB-­‐tE3x18.  

Management NATURAL  ENEMIES  

Although many  parasitoids  (small  wasps  and  a  flies)  and  parasites  have  been  recorded,  few   appear  to  impact  on  populations  of  the  bug,  except  for  one,  Trissolcus  basalis  an  egg  parasitoid   that  exists  as  several  strains.  In  Brazil  for  instance,  this  insect  is  mass-­‐reared  for  release  in   soybeans.  In  many  counties,  ants  are  said  to  achieve  high  levels  of  biocontrol.  One  ant   common  in  Solomon  Islands  -­‐  the  Big-­‐headed  ant,  Pheidole  -­‐  is  said  to  take  the  eggs  and  young   nymphs  to  its  nest.    CULTURAL  CONTROL  

• • •

Avoid planting  crops  of  beans  next  to  older  infested  ones  as  the  bugs  easily  fly  to  the  new   crop;   Weed  around  the  crop,  as  many  weeds  are  breeding  hosts  for  the  Green  vegetable  bug;   Plant  a  trap  crops  such  as  Rattle  pod,  Crotalaria;  the  bug  favours  the  Crotalaria  rather  than   the  crop.    

CHEMICAL CONTROL  

Use synthetic  pyrethroid  insecticides,  such  as  lambda  cyhalothrin  or  permethrin.  The   choice  of  chemical  is  important:  use  those  that  are  least  persistent  in  the  environment,   and  have  low  toxicity  against  bees.     Derris  (rotenone)  may  be  effective  against  the  beetle.  A  variety  of  Derris,  brought  many   years  ago  from  Papua  New  Guinea,  may  be  effective  as  a  spray.  It  contains  rotenone,  an   insecticide.  Plants  are  being  multiplied  by  MAL  and  KGA  for  evaluation  by  growers.  Contact   those  organisations  for  plants  to  test.  

      AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Turnip Mosaic    

Extension Fact  Sheet  

99

Common  name:  Turnip  mosaic     Scientific  name:  Turnip  mosaic  potyvirus.  The  abbreviation  for  this  virus  is  TuMV.   Hosts:  Many,  especially  brassicas,  including  cauliflower,  broccoli,  cabbage  and  radish.  In   Solomon  Islands,  Chinese  cabbages,  Brassica  chinensis,  are  hosts.  The  virus  also  infects  lettuce   and  spinach,  and  some  ornamentals,  including  zinnia  and  petunia.    

Damage   A  virus  causes  the  disease.  The  mosaic  symptom  describes  patterns  of  dark  and  light  green  on   the  leaves.  The  darker  green  areas  often  occur  either  side  of  major  veins  (photo).  TuMV  is  the   most  important  and  widespread  virus  disease  affecting  brassicas.  The  affected  plants  are  not   suitable  for  the  market.    

Biology and  Life  Cycle   TuMV  is  transmitted  rapidly  in  a  non-­‐persistent  way  by  several  aphid  species;  this  means  that   the  virus  does  not  multiply  inside  the  aphid.  As  the  aphids  feed,  the  virus  sticks  to  the  needle-­‐ like  mouthparts  used  to  pierce  and  suck  out  plant  sap  from  a  leaf.  When  the  aphid  feeds  on   another  leaf,  the  contaminated  mouthparts  transfer  the  virus.  The  virus  is  not  transmitted  in   seed.       Mechanical  transmission  or  the  transfer  of  sap  from  an  infected  plant  to  one  that  is  healthy   can  also  spread  the  virus,  but  the  importance  of  this  method  compared  to  spread  by  aphids  is   not  known.  The  absence  of  aphids  on  diseased  plants  is  of  little  significance.  Aphids  often   alight  on  a  crop,  fee  and  fly  on  if  it’s  not  to  their  liking.    

Detection and  Inspection   Look  for  leaves  with  distinct  light  and  dark  green  patches.   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Management Control  of  TuMV  is  difficult.  The  virus  has  a  wide  host  range,  insecticides  do  not  prevent  its   spread,  and  there  are  several  strains.  Once  the  plants  are  infected  with  TuMV  and  show   symptoms  there  is  no  way  to  make  them  healthy  again,  so  it  is  important  to  prevent  infection.  

CULTURAL CONTROL   • • •

• •

Avoid planting  any  of  the  crops  known  to  be  susceptible  to  TuMV  next  older  crops  of   susceptible  species;  if  you  do,  aphids  will  quickly  move  the  virus  to  the  new  crop;   In  particular,  avoid  planting  down-­‐wind  from  an  infected  crop;  adult  winged  aphids  can  be   carried  by  wind  onto  the  healthy  crop;   Check  plants  in  the  nursery  for  TuMV  symptoms;  if  found  remove  and  destroy  them,  and   check  the  remainder  frequently.  Continue  to  check  seedlings  when  transplanted  to  the   field;   But,  be  careful  when  handling  infected  seedling.  Be  careful  too  when  transplanting   seedlings  to  the  field.  Wash  hands  frequently  with  soap  and  water;   Weed  around  nurseries  and  crops  in  the  field,  as  many  weeds  are  hosts  of  TuMV.  Note   that  some  weeds  do  not  show  symptoms,  but  can  still  be  a  source  of  the  virus.  

RESISTANT VARIETIES   Resistant  varieties  of  Chinese  cabbage  are  available,  but  none  are  resistant  to  the  several   strains  of  TuMV  that  exist.    

CHEMICAL CONTROL   This  is  not  an  option.  Insecticides  take  time  to  kill  insects;  by  the  time  the  aphids  are  dead,   they  have  already  fed  and  passed  on  the  virus.  Sprays  of  mineral  oil  (see  Fact  Sheet  no.  56d)   may  be  useful  to  repel  aphids.    

   

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Cucumber Mosaic    

Extension Fact  Sheet  

100

Common  name:  Cucumber  mosaic     Scientific  name:  Cucmber  mosaic  cucumovirus.  The  abbreviation  for  this  virus  is  CMV.   Hosts:  Many,  especially  in  the  families  Curbitaceae,  Fabaceae  and  Solanaceae,  including  in   Solomon  Islands:  cantaloupe  melon,  capsicum,  chilli,  pumpkin,  snake  gourd,  tomato  and   watermelon.  CMV  has  also  been  found  in  two  weeds:  Ruellia  and  Synedrella.    

Damage CMV  is  a  common  virus  widespread  in  many  crops.  It  causes  mottles  and  mosaics;  terms  used   to  describe  patterns  of  dark  and  light  green  on  the  leaves.  For  most  plants  the  symptoms  are   indistinct,  especially  in  chilli,  tomato  and  pumpkin,  hosts  where  CMV  is  unlikely  to  cause  yield   losses.  However,  CMV  often  occurs  with  other  viruses,  eg  in  chilli  (see  Fact  Sheet  no.  5),  and   symptoms  can  be  severe.  In  Solomon  Islands,  CMV  has  been  found  with  Zucchini  yellow  mosaic   virus,  Papaya  ringspot  virus,  Tobacco  mosaic  virus  and  Tomato  mosaic  virus.     In  snake  gourd  (photo,  middle),  leaf  symptoms  vary:  some  leaves  have  faint  spots  and  blotches   roughly  following  the  veins,  others  have  large  areas  of  yellow  (photo,  right),  and  other  still   show  distortions  with  clear  patches  of  yellow  and  darker  green  (photo,  centre).  In  banana,  the   situation  is  less  certain.  Virus  surveys  have  not  recorded  CMV,  but  symptoms  on  the  weather   coast  of  Makira  suggest  that  the  virus  is  present  in  that  host.  Here  the  symptoms  show  a  light   yellow  streaking  on  the  leaves,  with  some  of  the  streaks  turning  brown  (photo,  left).  There  is   no  evidence  that  infection  damages  the  fruits  or  lowers  yield.  

  AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Biology and  Life  Cycle   CMV  is  spread  by  seed  in  some  species,  but  rates  are  usually  low,  eg  tomato.  It  is  transmitted   rapidly  in  a  non-­‐persistent  way  by  several  aphid  species.  It  takes  a  few  seconds  for  aphids  to   acquire  the  virus,  and  then  they  can  pass  it  on  during  the  next  minute  or  two;  this  is  what  is   meant  by  “non-­‐persistent”.  As  aphids  feed,  the  virus  sticks  to  their  needle-­‐like  mouthparts  that   they  use  to  pierce  leavces  and  suck  up  the  plant  sap.  The  next  time  the  aphids  feed,  the  virus   on  the  mouthparts  is  placed  inside  the  leaf;  if  this  is  a  leaf  on  a  healthy  plant,  it  now  becomes   infected.  The  virus  does  not  multiply  inside  aphids.       Then  absence  of  aphids  on  diseases  plants  is  of  little  significance.  Aphids  often  alight  on  a  crop,   feed  and  fly  on  if  it’s  not  their  liking.     Mechanical  transmission  or  the  transfer  of  sap  from  an  infected  plant  to  one  that  is  healthy   can  also  spread  the  virus,  but  it  is  thought  to  be  less  important  than  spread  by  aphids.      

Detection and  Inspection  

Look for  leaves  with  light  and  dark  green  patches.  In  some  hosts,  the  leaves  may  be  distorted.  

Management Control  of  CMV  is  difficult.  It  has  a  wide  host  range,  insecticides  do  not  prevent  its  spread,  and   there  are  several  strains.  Once  the  plants  are  infected  with  CMV  and  show  symptoms  there  is   no  way  to  make  them  healthy  again,  so  it  is  important  to  prevent  infection.  

CULTURAL CONTROL   • • • • • •

Only use  virus-­‐free  seed;  if  keeping  seed  make  sure  it  is  taken  from  plants  that  appear  free   from  virus  symptoms;   Avoid  planting  any  of  the  crops  known  to  be  susceptible  to  CMV  next  to  older  crops  of   susceptible  species;  if  you  do,  aphids  will  quickly  move  the  virus  to  the  new  crop;   In  particular,  avoid  planting  down-­‐wind  from  an  old  crop;  adult  winged  aphids  can  be   carried  by  wind  onto  the  healthy  crop;   Check  plants  in  the  nursery  for  CMV  symptoms;  if  found,  remove  and  destroy  them.  Check   the  remaining  plants  in  the  nursery  frequently  as  well  as  those  planted  in  the  field.       But,  be  careful  when  handling  infected  seedling.  Be  careful,  too,  when  transplanting   seedlings  to  the  field.  Wash  hands  and  tools  frequently  with  soap  and  water;   Use  a  trap  crop;  plant  resistant  varieties  or  types  of  vegetables,  or  root  crops  that  do  not   become  infected,  around  the  susceptible  crop;  by  the  time  the  aphids  reach  the   susceptible  varieties  they  will  have  lost  the  virus;   Weed  around  nurseries  and  crops  in  the  field  as  many  weeds  are  hosts  of  CMV,  and  two   have  been  proven  to  be  so  in  Solomon  Islands.  Note  that  some  weeds  do  not  show   symptoms,  but  can  still  be  a  source  of  the  virus.  

RESISTANT VARIETIES   There  are  varieties  of  cucumber  and  courgette  (zucchini)  that  have  some  resistance  to  CMV.  

CHEMICAL CONTROL   Do  not  use  insecticides.  By  the  time  they  have  killed  aphids  they  have  already  fed  and  passed   on  the  virus.  Sprays  of  mineral  oil  may  be  useful  to  repel  aphids,  and  they  also  interfere  with   virus  transmission.   AUTHORS  Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S  

Bacterial Stem  Rot    

Extension Fact  Sheet  

101

Common  name:  Bacterial  stem  rot     Scientific  name:  Erwinia  species.   Host:  Chinese  cabbage.    

Damage This  is  a  disease  caused  by  bacteria.  A  wet  soft  rot  develops  at  the  base  of  the  leaf  stalks.     Serious  losses  can  occur  in  Chinese  cabbage  crops,  especially  during  hot  wet  weather.    

Biology and  Life  Cycle   The  bacteria  live  in  the  soil.  Infections  occur  through  wounds  caused  by  insects  or  injury  at   planting  or  when  weeding.  The  disease  usually  starts  on  the  underside  of  the  lower  leaves   close  to  the  soil.  A  grey  watery  rot  rapidly  develops  (photo,  arrowed)  with  a  strong  smell.  The   rot  quickly  spreads  to  the  entire  plant  and  it  collapses  and  dies.  As  the  plants  die  the  bacteria   are  released  into  the  soil.    

Detection and  Inspection   Look  for  leaves  that  have  wilted,  and  show  grey  rots  at  the  base  of  the  stems.  This  is  called  a   water-­‐soaked  symptom.  First  the  outer  leaves  wilt,  and  then  the  whole  plant.  

Management CULTURAL  CONTROL   Cultural  practices  are  important  in  preventing  outbreaks  of  this  disease.  Do  the  following:     •

Avoid waterlogging:  plant  Chinese  cabbage  on  raised  beds;      

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


M I N I S T R Y O F   A G R I C U L T U R E   A N D   L I V E S T O C K   |   S O L O M O N   I S L A N D S   • •

• • •

Do not  plant  Chinese  cabbages  too  close  to  each  others:  allow  wind  movement  between   the  plants;   Mulch  plants  with  straw,  dried  grass  or  whatever  is  available;  this  is  important  as  it  not   only  conserves  water  during  dry  times,  but  also  stops  bacteria  being  splashed  from  the  soil   onto  the  plants  during  heavy  rains;     Be  careful  when  weeding  the  plants  so  as  not  to  damage  the  leaves  and  allow  entry  of   bacteria;   Remove  plants  with  signs  of  stalk  rot  as  soon  as  it  appears,  and  burn  them;   Remove  crops  debris  or  bury  it  deeply  in  the  soil  before  a  new  crop  is  planted;  preferably   allow  a  few  months  for  the  crop  remains  to  decompose  before  planting  another  crop  of   Chinese  cabbage;   Rotate  the  land  with  other  crops  that  are  resistant  to  this   disease,  eg  beans,  cucumbers  or  tomatoes.  

RESISTANT VARIETIES   The  variety  Pak  Choy  (photo,  right)  is  especially  susceptible  to  this   disease,  so  try  other  kinds  of  Chinese  cabbage.  

CHEMICAL CONTROL   This  is  not  an  option  for  this  soil  borne  disease,  unless  the  problem  is  associated  with  soil   insects.  In  this  case,  use,  for  instance,  imidacloprid.    

AUTHORS Helen  Tsatsia  •  Grahame  Jackson   HT  works  for  MAL;  GJ  is  with  TerraCircle  Inc.  

Produced with  support  from  IPPSI:   Improved  Plant  Protection  in  Solomon   Islands,  funded  by  ACIAR,  Canberra  

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Coconut Stick  Insect    

Extension Fact  Sheet  

102

Common  name:  Coconut  stick  insect   Scientific  name:  Graeffea  crouanii1.   Host:  Coconut,  sago  palm,  pandanus  and  some  wild  palms   Distribution:  South  west  Pacific,  including  Fiji,  Samoa  and  Tonga,  but  not  Solomon  Islands    

Damage The  adults  (photo,  left2)  and  nymphs  do  the  damage.  Damage  is  worse  on  the  older  leaves  as   the  stick  insects  have  had  longer  to  feed  on  them  (photo,  below).  The  older  leaves  may  be   stripped  bear  leaving  only  the  midribs  (photo,  below3).  The  damage  is  worse  on  palms  that  are   over  25  m  tall.  In  Fiji  and  Samoa,  defoliation  sometimes  occurs  over  several  hundred  hectares,   but  the  damage  occurs  only  at  irregular  intervals.  In  Fiji,  defoliation,  crop  loss  and  death  of   palms  have  been  reported.  

Biology and  Life  Cycle   Eggs  are  laid  by  females  in  the  crown  of  the  palms,  and  fall  into  the  base  of  the  leaves,  or  to   the  ground  where  they  remain  in  leaf  litter  and  among  weeds.  They  hatch  in  about  12-­‐16   weeks.  The  nymphs  -­‐  tiny  versions  of  the  adults  -­‐  make  their  way  up  the  trunks  if  they  hatched   on  the  ground,  or  from  the  leaf  axils,  to  feed  on  the  leaflets.  There  are  five  or  six  moults  for   males  and  females,  respectively.  When  adult,  they  are  green  or  pinkish  brown,  with  pink,  short   wings,  allowing  them  to  blend  in  with  the  leaflets.  From  egg  to  adult  is  about  3.5  months  for   males  and  4  months  for  females.  Only  males  can  fly  (see  wings:  photo,  left).  Both  adults  and   nymphs  feed  at  night  and  hide  during  the  day  at  the  base  of  the  leaflets.      

Detection and  Inspection  

Look for  leaflets  eaten  at  the  margins;  look  for  large  insects  with  characteristic  shape  -­‐  long,   thin  bodies  and  very  long  legs;  the  females  are  green  up  to  120  mm  long  and  6  mm  wide,  and  

1

Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press. 2 Photos of stick insects by Gerald McCormack, Cook Islands Biodiversity & Natural Heritage: http://cookislands.bishopmuseum.org/. 3

Photo of defoliation of coconuts (Richard Markham, ACIAR)

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   the  males  brown  and  70  mm  long  and  3  mm  wide.  Look  for  the  small  wings.  The  stick  insects   discharge  a  smelly  liquid  if  handled  roughly.  

Management NATURAL  ENEMIES   Chickens  readily  eat  the  stick  insects  as  do  myna  birds,  but  not  enough  to  control  populations.   Skinks  also  eat  the  eggs.  Ants  and  preying  mantids  are  said  to  provide  some  control,  but  they   are  probably  not  effective  predators.     Parasitic  wasps,  especially  Paranastatus  verticalis  and  P.   nigriscutellatus,  have  been  recorded  from  eggs  in  Fiji  and   Tonga.  P.  verticalis  has  been  bred  occasionally  in  Fiji  to   control  high  populations  of  Graeffea.  Both  species  were   imported  into  Samoa  from  Fiji  and  became  established.  P.   verticalis  was  released  into  Tonga  in  1977  and  became   established  there.  

CULTURAL CONTROL   Cultural  practices  are  important  in  preventing  outbreaks   of  this  insect.  Do  the  following:     •

• •

Burn palm  fronds  under  the  palms  on  still  days   causing  the  stick  insects  to  fall  to  the  ground,  where   they  can  be  eaten  by  chickens  or  killed  by  hand.  Note,   although  effective,  the  fires  damage  the  coconut   palms  and  the  method  is  no  longer  used  in  most  countries.   Use  horticultural  glue  bands  around  the  trunks.  The  glue  is  a  non-­‐drying  sticky  substance   made  from  natural  gum  resins,  vegetable  oil  and  wax  that  prevents  crawling  nymphs  from   reaching  the  coconut  leaves.  One  such  product  is  called  Tanglefoot.   Control  weeds  under  coconuts.  Doing  so  exposes  the  eggs  to  the  sun,  and  eggs  and  young   nymphs  to  chickens  and  ants,  particularly  the  big-­‐headed  ant,  Pheidole  megacephala.   Plant  cocoa  beneath  coconuts.  Unpublished  accounts  in  Samoa  suggest  that  some  nymphs   starve  to  death  by  mistakenly  climbing  cocoa  trees  rather  than  coconut  palms.    

RESISTANT VARIETIES   None  known.  

CHEMICAL CONTROL   Use  of  insecticides  on  young  palms  is  feasible,  but  applications  on  mature  palms  are  not   possible  from  the  ground.  If  insecticides  are  necessary,  use  sprays  of  a  synthetic  pyrethroid   (for  example,  lambda  cyhalothrin).       Previously,  bands  of  insecticide  with  long  residual  life,  such  as  dieldren,  were  painted  on  the   trunks;  however,  such  chemicals  are  no  longer  recommended,  and  in  many  cases  banned   under  international  treaties.  Similarly,  trunk  injections  using  systemic  chemicals,  such  as   monocrotophos  and  aceophate,  were  once  used  routinely  in  Fiji,  and  were  researched  in   Samoa.  They  were  effective,  but  had  the  disadvantage  in  allowing  the  entry  of  fungal   pathogens  that  may  kill  the  palm.  Note,  monocrotophos  is  a  highly  toxic  organophosphate  and   is  banned  in  many  countries.  

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Banana Aphid    

Extension Fact  Sheet  

103

Common  name:  Banana  aphid   Scientific  name:  Pentalonia  nigronervosa1.   Host:  Banana,  other  Musa  spp.,  and  relatives  -­‐  Heliconia,  Strelitzia  and  Ravenala;  other  hosts   are  Canna  and  Zingiber  species  (gingers),  and  some  Aracae,  including  taro  and  Xanthosoma.   Distribution:  Worldwide.  It  has  been  reported  in  Fiji  (where  it  was  first  described),  Samoa,   Solomon  Islands  and  Tonga,  and  many  other  Pacific  island  countries.    

Damage Pentalonia  aphids  (photo,  left)  damage  plants  in  three  ways:  they  take  nutrients  and  water   from  the  plants  by  feeding  on  their  sap,  by  producing  honeydew  that  attracts  dark  fungi  called   sooty  moulds,  and  by  spreading  viruses.  Insects  that  spread  viruses  in  this  way  are  called  virus   vectors.     Sometimes,  large  colonies  of  Pentalonia  kill  banana  suckers,  but  this  is  probably  rare.  Large   colonies  may  sometimes  mark  fruits,  but  this,  too,  is  unusual.  Sooty  mould  fungi  grow  on  aphid   honeydew,  but  damage  to  plants  is  not  common,  although  there  are  reports  of  moulds  at  the   base  of  leaves  causing  rots.       Major  damage  is  caused  spread  of  a  virus  called  Banana  bunchy  top  virus  (BBTV)  (photo,   right2).  In  parts  of  Samoa  and  Tonga,  the  disease  caused  by  this  virus  has  stopped  commercial   banana  production.  Young  aphids  -­‐  the  nymphs  -­‐  are  more  efficient  at  spreading  the  virus,  but   it  is  more  likely  that  winged  adults  start  new  infections.  Pentalonia  has  long  mouthparts  called   stylets  that  pierce  plants  to  suck  sap  from  the  phloem  –  the  tubes  that  take  nutrients  from  the   leaves  to  the  roots.  Aphids  pick  up  the  virus  after  feeding  on  infected  bananas  for  about  18   hours,  and  keep  it  for  the  rest  of  their  lives  (15-­‐20  days).     1

Much of the information given here comes from Waterhouse DE, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press. 2 Photo of BBTV symptoms (Richard Markham, ACIAR). AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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Biology and  Life  Cycle   Males  are  unknown,  so  reproduction  occurs  without  fertilisation  -­‐  known  as  parthenogenesis.   Eggs  are  also  unknown;  instead,  females  give  birth  to  living  young  –  known  as  viviparity.  Two   to  four  young  are  born  each  day.  The  nymphs  go  through  four  moults.  When  adult  they  are  up   to  1.5  mm  long,  shiny,  red-­‐brown  or  almost  black,  usually  wingless.  Winged  adults  appear  after   7-­‐10  generations.  The  wings  have  characteristic  dark  veins.  Aphids  are  not  strong  flyers,  but   travel  long  distances  on  light  winds.  They  are  most  abundant  in  the  wet  season.  

Detection and  Inspection   Look  for  colonies  near  the  midrib  on  the  underside  of  the  leaf,  under  the  sheath  that  wraps   around  the  stem,  or  on  the  fruit.  Look  for  brown-­‐black  aphids  with  prominent  black  wing  veins.   Look  for  ants  that  are  attracted  to  the  aphids’  honeydew.  Colonies  may  occur  below  the  soil.  

Management Control  of  Pentalonia  is  mostly  associated  with  the  control  of  BBTV  for  which  it  is  the  vector.   (See  also  Fact  Sheet  no.  38:  Aphids).  

NATURAL ENEMIES   In  Samoa,  two  predacious  ladybird  beetles  were  imported,  and  in  Tonga  two  braconid  wasp   parasites,  Lysiphlebus  spp.  None  of  these  introductions  reduced  BBTV  to  acceptable  levels.   Indigenous  lacewings  and  syrphid  fly  larvae  also  attack  aphid  colonies.      

CULTURAL CONTROL   Cultural  practices  are  important  in  preventing  outbreaks  of  this  disease.  Do  the  following:     • • •

Maintain good  weed  control  around  the  banana  patch;  some  weeds  may  host  Pentalonia.   Check  alternative  hosts  for  aphid  populations,  and  eliminate  as  necessary  (see  below).   Keep  banana  mats  pruned  of  unwanted  suckers.  Aphids  prefer  to  feed  on  young  suckers.  

RESISTANT VARIETIES   Pentalonia  is  not  normally  found  on  plantains.  However,  all  Musa  species  and  varieties  are   susceptible  to  BBTV.  In  Australia,  variety  Gros  Michel  is  more  resistant  to  BBTV  than  Dwarf   Cavendish.  In  Fiji,  variety  Veimama  shows  resistance;  it  may  be  infected  by  a  mild  BBTV  strain.

CHEMICAL CONTROL   Killing  the  aphids  on  the  bananas  as  soon  as  symptoms  are  seen  is  important.  Do  the  following:     • Strip  away  old  leaf  sheaths  from  around  the  base  of  the  plants.   • Kill  the  aphids  on  the  plants  by  one  of  the  following  methods,  spraying  the  stem   thoroughly  with  insecticide,  paying  special  attention  to  the  “throat”  and  funnel  leaves.   Spray  each  of  the  suckers.   o Use  any  one  of  the  synthetic  insecticides  recommended  in  the  Pacific  Islands,  e.g.,   acephate,  diazinon,  dimethoate  or  malathion.  Of  the  newer  insecticides,  use   Imidacloprid  or  synthetioc  pyrethroids  (e.g.,  lambda  cyhalothrin  or  cypermethrin).   o Use  horticultural  soaps,  oils  and  dishwashing  detergents  (see  Fact  Sheet  no.  56d).   o Use  kerosene,  or  a  mixture  of  diesel  and  mineral  oil.   • After  1  week,  either  spray  the  infected  plants  with  herbicide  (glyphosate)  or  put  a  K-­‐pin   (containing  the  herbicide  picloram)  into  the  stem.   • Remove  the  dead  plants  and  burn  them.   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Coconut Scale    

Extension Fact  Sheet  

104

Common  names:  Coconut  scale;  Transparent  scale   Scientific  name:  Aspidiotus  destructor1.   Hosts:  Especially  coconuts  and  banana,  but  also  avocado,  breadfruit,  cassava,  guava,  oil  palm,   sugarcane.   Distribution:  Worldwide.  Reported  from  Fiji,  Samoa  and  Solomon  Islands,  but  not  Tonga.      

Damage

Mostly the  scales  occur  in  the  underside  of  leaves,  but  in  heavy  infestations  they  colonise  the   upper  surface,  flowers  and  fruit.  Infestations  cause  the  fronds  to  yellow  as  the  scales  feed  and   inject  toxic  saliva.  In  extreme  cases,  leaves  dry,  fall  and  palms  die.         Note  that  the  scale  is  present  in  Fiji,  Samoa  and  Solomon  Islands,  but  it  is  not  a  pest  in  these   countries.  Tonga  has  a  vulnerability  to  this  scale.  

Biology and  Life  Cycle   Eggs  are  laid  under  the  scale  cover;  they  hatch  and  crawlers  emerge,  which,  as  the  name   suggests,  have  legs;  they  crawl  over  the  host  plant  to  find  a  place  to  feed.  Within  12  hours  they   settle,  form  a  scale  cover  and  moult,  losing  legs  and  antennae.  The  scale  is  whitish,  waxy,   translucent,  flexible  and  1.5-­‐2  mm  across  (photo2).  Body  parts  of  the  circular  females  can  be   seen  beneath.  The  male  scale  is  more  oval  and  smaller.  Males  moult  to  form  prepupae,  and   then  moult  again  to  form  pupae.  During  these  moults  there  are  signs  of  wings  and  other   appendages.  The  adult  male  has  eyes,  legs,  antennae,  and  wings,  but  no  mouthparts.  After  a   day  under  the  scale  it  emerges  to  fertilise  nearby  females.       However,  fertilisation  is  not  essential;  unfertilised  females  give  birth  to  males  and  females.  The   entire  life  cycle  is  about  30  days,  and  females  lay  about  90  eggs  over  a  period  of  a  week  or  so.   1 Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press. 2 Photo of adult Aspidiotus (Gillian Watson, Senior Insect Biosystematist, Plant Pest Diagnostics Branch, California Department of Food & Agriculture, Sacramento, CA, USA).

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   Apart  from  the  ability  of  crawlers  to  walk,  they  can  be  spread  widely  by  wind,  flying  insects,   birds  and  by  human  beings.  

Detection and  Inspection   Look  for  almost  circular,  whitish,  waxy  scales,  so  thin  that  the  yellowish  body  of  the  insect  can   be  seen  beneath.  Look  for  coconut  leaflets  that  are  covered  with  a  yellow  crust  of  scales  when   there  are  heavy  infestations.  

Management The  management  of  coconut  scale  is  entirely  based  on  biological  control,  which  throughout   the  world  has  been  very  successful.  It  was  been  due  to  introductions  of  coccinellid  beetles  and   wasp  parasitoids.    

QUARANTINE The  absence  of  the  Coconut  scale  from  Tonga  requires  that  quarantine  authorities  take   precautions  against  its  introduction.  The  FAO/IBPGR  Technical  Guidelines  for  the  Safe   Movement  of  Coconut  Germplasm  should  be  followed  when  imports  of  coconuts  are  made   (see,  http://pdf.usaid.gov/pdf_docs/PNACH919.pdf).  But  note  that  the  scale  has  a  wide   host  range,  and  precautions  should  be  taken  when  importing  plants  of  any  kind.  

NATURAL ENEMIES   Control  of  Coconut  scale  outbreaks  began  in  Fiji  in  the  1920s.  Wasp  parasitoids  were  collected   from  Java,  and  coccinellids  from  Trinidad.  Of  all  those  introduced,  the  ladybird  beetle,   Cryptognatha  nodiceps  (and  later  C.  gemellata)  were  the  most  useful  in  rapidly  bringing  the   scale  under  control.  It  is  said  that  the  beetle  eats  large  quantities  of  coconut  scales  and  has  a   preference  for  this  insect.  Another  coccinellid,  Rhyzobius  satelles,  was  introduced  in  the  1970s.   Good  control  has  continued  except  where  ants  are  present  attending  the  scales  for  their   honeydew.     The  scale  is  rare  in  Solomon  Islands,  where  a  number  of  coccinellid  predators  are  present:   Chilocorus,  Cryptolarmus  montrouzieri  (known  as  the  Mealybug  ladybird),  Rhyzobius  and   Scymnus.   Note,  Pseudoscymnus  anomalus  is  said  to  be  a  specific  coccinellid  predator  of  Coconut  scale   and  is  present  in  Micronesia.  It  had  been  effective  against  the  Coconut  scale  in  Vanuatu.  

CULTURAL CONTROL   In  the  early  stages  of  infestations,  remove  fronds  colonised  by  the  Coconut  scale.  

RESISTANT VARIETIES   None  known

CHEMICAL CONTROL   Insecticides  may  be  useful  on  young  palms,  but  not  those  that  are  mature  because  the  crowns   are  to  high  to  reach.  There  is  also  the  likelihood  that  insecticides  will  destroy  predators  and   parasitoids  and  delay  bringing  about  natural  and  sustained  control  of  the  Coconut  scale.  If   chemicals  are  needed,  use  white  oil  (see  Fact  Sheet  no.  56d).      

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Citrus Snow  Scale    

Extension Fact  Sheet  

105

Common  names:  Citrus  snow  scale,  White  louse  scale   Scientific  name:  Unaspis  citri1.   Hosts:  Almost  exclusively  Citrus  spp.,  but  the  Pacific  banana  is  a  host.   Distribution:  Tropics  worldwide.  It  is  present  in  Fiji,  Samoa,  Solomon  Islands  and  Tonga.    

Damage The  scale  (photo2)  occurs  mostly  on  the  trunk  and  large  branches,  except  in  heavy  infestations   when  it  spreads  to  the  twigs,  leaves  and  fruit.  Heavy  infestations  cause  leaves  to  yellow  and   fall,  twigs  to  dieback  and  entire  branches  to  die.  The  weakening  of  the  trees  in  this  way  can   lead  to  fungal  rots  and  invasion  by  wood-­‐boring  insects.       Even  after  the  scale  has  been  brought  under  control,  damage  may  still  occur.  The  bark  of   previously  infested  trees  does  not  expand  properly  as  inner  tissues  grow,  resulting  in  splitting   and  then  invasion  by  other  pests.     Populations  are  higher  and  damage  is  worse  in  dry  times.  It  has  been  reported  to  be  a  locally   important  pest  of  oranges  and  lemons  in  Fiji,  and  a  major  pest  and  a  constraint  to  growing   West  Indian  limes  in  Samoa.  In  Solomon  Islands,  Waterhouse  and  Norris  state  that  it  is  among   the  10  worst  pests  of  the  country,  “…  causing  widespread  and  serious  damage  every  year”.    It   is  also  important  in  Tonga.    

Biology and  Life  Cycle   The  male  and  female  scales  look  quite  different.  The  female  is  oval,  oyster-­‐shaped  and  brown-­‐ black;  it  is  a  little  over  2  mm  long.  The  male  is  much  smaller,  1  mm  long,  oval  and  white.  Both   have  ridges  running  the  lengths  of  their  bodies.  Numerous  white  males  on  trunks  and  branches   give  the  appearance  of  snow,  hence  its  common  name.       1

Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press. 2 Photo of adult scale (Gillian Watson, Senior Insect Biosystematist, Plant Pest Diagnostics Branch, California Department of Food & Agriculture, Sacramento, CA, USA). AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   Eggs  hatch  and  the  crawlers  move  to  new  sites  on  the  same  tree;  they  are  spread  further  afield   by  wind,  on  birds,  other  animals  and  human  beings.  They  eventually  settle  in  crevices  in  the   bark,  start  to  feed  and  form  protective  scales  over  their  bodies.  Males  moult  twice  and  females   four  times,  the  last  two  are  the  pre-­‐pupa  and  pupa  stages  with  signs  of  adult  features.  The   adult  male  is  orange,  with  eyes,  antennae  and  one  pair  of  wings,  but  no  mouthparts.         The  females  are  fertilised,  the  males  then  die,  usually  within  a  few  hours,  and  the  females   soon  starts  laying  eggs.  Unfertilised  females  also  lay  eggs  and  these  develop  as  females.  The   entire  life  cycle  is  2-­‐3  months  depending  on  temperatures.    

Detection and  Inspection   Look  for  large  white  masses  of  the  male  scales,  which  are  very  distinctive.  The  darker  oval   female  scales  are  more  difficult  to  detect  as  they  are  small  and  do  not  occur  in  large  numbers   in  any  one  place.  Critical  identification  needs  microscopic  examination  of  the  females.  

Management The  management  of  the  Citrus  snow  scale  is  based  on  biological  control,  and  in  some  countries   the  use  of  insecticides.    

NATURAL ENEMIES   There  are  a  large  number  of  natural  enemies  of  Citrus  snow  scale.  These  fall  into  three  groups:   parasitoid  wasps,  predacious  caterpillars  and  ladybird  beetles.  Of  the  many  listed,  two  Asian   wasps,  Aphytis  lingnanensis  and  A.  gordonae  have  greatest  potential.  However,  different   strains  exist  with  different  effectiveness  against  scale  populations.  A.  lingnanensis  was   introduced  into  Solomon  Islands  for  control  of  Citrus  snow  scale  in  1976,  but  its  establishment   is  unknown.  In  Australia,  the  caterpillar  of  a  moth,  Batrachedra  arensella  feeds  on  the  scale.   Many  coccinellids  eat  the  scale;  Scotoscymnus  prapawan  has  been  released  in  Vanuatu.  

CULTURAL CONTROL   • • •

Check that  nursery  stock  are  free  from  scale;  prune  infested  parts,  and  spray  with   insecticides  if  present.   Establish  windbreaks  of  Gliricida  to  reduce  infestations  by  crawlers  carried  on  the  wind.   Ensure  the  citrus  trees  are  well  cared  for  with  adequate  nutrition.  

RESISTANT VARIETIES   Nothing  is  reported,  but  see  comments  in  Damage  section  above  for  susceptible  species.

CHEMICAL CONTROL   Sulphur,  dimethoate  and  malathion  have  been  used,  but  the  waxy  coverings  protect  the  scales   from  chemical  sprays.  Crawlers  are  more  susceptible  to  insecticides  than  other  stages,  but   they  are  difficult  to  see  because  they  are  so  small.  There  are  also  overlapping  generations,  so   that  means  there  are  always  adults  present,  so  several  applications  of  chemicals  are  necessary   to  obtain  control.  And  adults  are  more  difficult  to  kill  because  of  their  protective  scales.     Note  that  lime  sulphur  stops  the  males  from  emerging  from  under  their  scales,  affects  the   production  of  the  scale  covering,  and  slows  reproduction.  Although  slow  acting  compared  with   modern  chemicals,  lime  sulphur  needs  only  to  be  sprayed  every  2-­‐3  years.  White  oil  is  also   useful  in  smothering  the  adult  scales,  and  can  be  used  with  or  without  dimethoate  or   malathion  against  the  crawlers  (see  Fact  Sheet  no.  56d).   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Melon Thrips    

Extension Fact  Sheet  

106

Common  name:  Melon  thrips   Scientific  name:  Thrips  palmi  (but  note,  no  species  of  palms  are  host!)1.   Hosts:  Recorded  on  many  plant  families,  including  cabbage,  cucumber,  legume,  potato  and   many  ornamentals  and  weeds.  Important  crops  hosts  are  French  beans,  capsicum,  eggplant,   melon,  potato,  tomato  and  zucchini.   Distribution:  Southeast  Asia,  India,  Japan,  the  Caribbean,  North  &  South  America,  and   widespread  in  the  Pacific,  including  Fiji,  Samoa,  Solomon  Islands  and  Tonga.    

Damage There  are  two  types  of  damage  caused  by  T.  palmi.  There  is  direct  damage  caused  by  feeding,   and  indirect  damage  caused  by  spreading  a  virus  disease  -­‐  Tomato  spotted  wilt  (TSWV).     Thrips  have  piercing  mouthparts  and  these  are  used  to  suck  out  cell  contents.  Major  damage   occurs  on  the  undersides  of  new  or  old  leaves,  especially  alongside  the  midribs  and  veins.   Large  numbers  of  thrips  cause  the  leaves  to  appear  silvery  or  brown,  and  to  curl  upwards,   becoming  boat-­‐like,  stunted  and  deformed.  Fruits,  too,  are  deformed  and  show  feeding  scars   (photo,  right2),  and  may  drop  prematurely.  

Biology and  Life  Cycle   T.  palmi  are  about  1  mm  long,  narrow,  yellow  with  two  pairs  of  wings  (photo,  left3).  Eggs  are   laid  in  young  leaves,  flowers  and  fruits;  they  hatch  in  3-­‐4  days  and  the  nymphs  look  like  adults   except  that  they  are  about  half  the  size  and  without  wings.  There  are  several  stages:  two  on   the  host  plants,  which  feed  actively  like  the  adults,  and  two  -­‐  the  pre-­‐pupae  and  pupae  -­‐  in  the   soil,  which  do  not  feed.  After  emergence  from  the  pupae  the  adult  burrows  to  the  soil  surface   and  then  climbs  or  flies  to  the  host  plant.  The  period  from  egg  laying  to  adult  emergence  is  10   to  12  days  at  30°C,  and  14  to  16  days  at  25°C.  The  adults  live  for  30-­‐90  days.  

1

Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific 2 Prospects. Inkata Press. J. Guyot, INRA, Pointe-a-Pitre, Bugwood.org. 3 Plant Protection Service Archive, Plant Protection Servoce, Bugwood.org. AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  insects  that  are  very  small,  narrow,  and  just  visible  to  the  naked  eye.  The  adults  are   yellow,  with  wings;  the  nymphs  are  yellow  or  white,  without  wings.  Look  for  the  silvering  or   bronzing  or  the  upper  sides  of  leaves,  especially  along  the  midribs  and  veins.  

Management The  management  of  T.  palmi  involves  reducing  the  damage  from  direct  feeding  as  well  as  the   damage  done  from  spreading  TSWV.  

NATURAL ENEMIES   Natural  enemies  are  not  well  recorded  for  T.  palmi,  although  there  have  been  introductions  of   predatory  bugs  (Orius  spp.)  and  parasitic  wasps  to  control  other  species  in  several  countries.  

CULTURAL CONTROL   • •

• •

Avoid overlapping  planting  of  susceptible  crops  to  minimise  spread  of  T.  palmi  from  one   crop  to  the  next.   Weed  around  crops,  destroying  hosts  of  thrips.  Weeds  that  are  flowering  are  particularly   attractive  to  thrips  as  they  feed  on  pollen.  If  using  herbicides,  destroy  weeds  well  before   planting,  not  as  crops  are  planted,  otherwise  the  thrips  may  migrate  from  the  wilted   weeds  to  the  young  crop  plants.   Make  sure  seedling  production  areas  are  well  away  from  field  crops,  and  kept  weed-­‐free.   Use  thrips-­‐proof  netting  for  seedling  production  areas  if  thrips  are  a  problem,  or  spray   regularly  with  an  insecticide.  

RESISTANT VARIETIES   There  are  varieties  of  capsicum  and  tomato  that  are  resistant  to  TSWV.  Use  these  varieties   together  with  cultural  control  measures  to  keep  populations  of  thrips  low;  otherwise,  the   resistance  may  fail  as  it  is  controlled  by  a  single  dominant  gene.  

CHEMICAL CONTROL   Note,  Insecticides  are  often  of  limited  value  in  TSWV  control  as  virus  spread  from  weeds  is  an   important  source  of  infection.  Also,  thrips  only  require  a  short  feeding  time  before  they  are   able  to  transmit  the  virus.  Use  insecticides  as  follows,  but  note  that  frequent  use  of   insecticides  may  also  lead  to  development  of  insecticide  resistance  in  thrips  populations.       • Spray  thrips  in  old  crops  as  soon  as  possible  after  harvest  as  they  are  a  major  source  of   virus,  and  a  threat  to  young  crops  especially  if  planted  nearby.   • Use  insecticidal  soaps  weekly;  they  are  highly  active  against  T.  palmi,  suffocating  the   insects  rather  than  poisoning  them.  The  spray  will  not  kill  all  of  the  thrips,  but  it  will   suppress  the  population  enough  to  allow  predator  and  parasite  numbers  to  build  up  and   start  to  control  them.   • Several  soap  sprays  will  be  needed  to  bring  the  thrips  under  control.  It  is  essential  that  the   underside  of  leaves  and  terminal  buds  are  sprayed  thoroughly  since  these  are  the  areas   where  the  thrips  congregate.  It  is  best  to  spray  between  4  and  6  pm  to  minimise  the   chance  of  leaves  becoming  sunburnt.   • Do  not  use  broad-­‐spectrum  insecticides  such  as  dimethoate,  malathion  and  permethrin.   They  have  a  greater  effect  on  the  natural  enemies  of  melon  thrips  than  on  the  thrips   themselves.   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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Rose beetle    

Extension Fact  Sheet  

107

Common  names:  Rose  beetle,  Indian  rose  beetle   Scientific  name:  Adoretus  versutus1.   Hosts:  Cocoa,  coffee,  yams,  many  other  crops,  ornamentals  and  trees,  e.g.  Hibiscus  tiliaceus.   Distribution:  South  Asia  and  some  countries  of  the  south  Pacific,  including  Fiji,  Samoa  and   Tonga,  but  not  Solomon  Islands.    

Damage The  adult  beetles  (photo,  left2)  do  the  damage,  feeding  in  the  early  hours  of  the  night.  As  they   eat,  they  make  holes  in  young  to  middle-­‐aged  leaves.  They  do  not  always  eat  the  midribs  and   veins,  so  the  patches  look  sieve-­‐like  or  skeletonised.  The  damage  is  locally  very  important  in   Fiji,  Samoa  and  Tonga.  In  Fiji,  cocoa  seedlings  and  plants  in  the  field  up  to  18-­‐months-­‐old  are   especially  vulnerable  to  attack,  with  10-­‐15%  of  young  trees  killed.  Tonga  has  recorded  damage   to  beans,  grapevines,  ginger  and  yams  (photo,  right3)  

Biology and  Life  Cycle   Brown  oval  eggs  (1.5-­‐2  mm  long)  are  laid  singly  in  the  soil  at  a  depth  of  7-­‐10  cm.  They  hatch  in   1-­‐2  weeks,  depending  on  temperature,  producing  C-­‐shaped,  fleshy,  whitish  grubs  with  strong   legs  that  go  through  three  stages  or  instars.  The  grubs  feed  on  organic  matter  and  roots.  Two   pupal  stages  follow,  lasting  about  25  days,  before  adults  emerge.  The  adult  Rose  beetles  are   about  12.5  long  and  6.5  mm  wide,  dark  brown  covered  with  dense  greyish-­‐white  scales  dotted   with  brown-­‐red  hairs.  The  whole  life  cycle  takes  about  80  days  in  Samoa.   In  the  daytime,  the  beetles  shelter  in  the  soil  or  under  leaves,  stones  and  logs.  However,  the   beetles  are  attracted  to  lights  at  night.    

  1 Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press. 2 Photo of rose beetle (Gerald McCormack, Cook Islands Biodiversity & Natural Heritage: http://cookislands.bishopmuseum.org/). 3 Photo of damage to yam, Dioscorea alata (Richard Markham, ACIAR)

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  brown  beetles  covered  with  grey-­‐white  scales;  look  for  the  characteristic  damage  to   the  leaves  where  the  beetles  eat  numerous  holes,  but  leave  the  veins  untouched.  Remove  the   soil  to  a  depth  of  10  cm  from  around  the  base  of  affected  plants  and  look  for  the  C-­‐shaped   larvae  with  orange  head  capsules.  Look  for  the  beetles  feeding  at  night.  

Management The  Rose  beetle  is  difficult  to  control  because  a  considerable  part  of  its  life  cycle  occurs  in  the   soil.  

NATURAL ENEMIES   A  scoliid  wasp,  Micromeriella  margiinella  modesta  was  introduced  into  Fiji  from  Hawaii  in   1917,  and  later  into  Samoa  (1955)  and  Solomon  Islands  (1984).  In  Fiji,  it  was  introduced   primarily  against  a  beetle  (Xenotrogus)  of  sugarcane.  Two  fungi  were  also  introduced  from   Hawaii  into  Fiji.  There  is  no  evidence  that  the  wasp  reduced  populations  of  Rose  beetle  or  that   the  fungi  became  established.  In  Samoa,  trials  showed  that  the  Rose  beetle  could  be  killed  by   the  baculovirus  (now  called  Oryctes  rhinoceros  nudivirus)  of  Oryctes,  and  the  fungus,   Metarhizium  anisopliae.  

CULTURAL CONTROL   • • •

Use barriers  (e.g.  coconut  fronds,  bamboo,  stones)  around  cocoa  seedlings  planted  in  the   field,  making  sure  they  are  at  least  as  tall  as  the  foliage.   Use  shade  in  cocoa  plantations:  if  the  shade  is  more  than  30-­‐40%,  the  damage  from  Rose   beetle  is  usually  low.   Handpick  and  destroy  adult  beetles  that  come  to  light  sources  as  night.  Note,  in  Samoa,   grubs  have  been  found  crawling  on  soil  at  night,  although  it  is  not  known  whether  they   were  doing  this  to  find  food  or  to  escape  overcrowding.  

RESISTANT VARIETIES   None  known  

CHEMICAL CONTROL   In  Tonga,  malathion  is  used  on  yams  when  leaf  damage  is  about  30%.  The  insecticide  is  applied   in  the  late  afternoon.  Trials  in  Samoa  showed  that  acephate  and  permethrin  were  superior  to   malathion.  

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Rhinoceros Beetle    

Extension Fact  Sheet  

108

Common  names:  Coconut  rhinoceros  beetle,  Rhinoceros  beetle   Scientific  name:  Oryctes  rhinoceros1.   Hosts:  Coconut  is  the  most  important  host,  but  other  palm  species  are  attacked,  including  sago   and  oil  palm.  Banana,  pandanus,  sugarcane  and  tree  fern  are  also  hosts.     Distribution:  South  and  Southeast  Asia  and  many  Pacific  island  countries,  including  Fiji,  Samoa   and  Tonga,  but  not  Solomon  Islands.    

Damage The  adult  beetles  (photo,  right2)  do  the  damage,  boring  into  the  crown  of  coconut  palms,   cutting  across  young  fronds  and  flowers.  When  the  leaves  unfold  the  damage  is  seen  as  V  or   wedge-­‐shaped  areas  missing  from  the  leaflets  (photo,  left).  This  type  of  damage  is   characteristic  of  the  beetle,  and  results  in  flowers  dying,  early  nut  fall  and,  ultimately,  lower   yields.  Occasionally,  the  beetles  bore  through  the  midribs  of  fronds,  which  snap  in  the  wind.       It  is  difficult  to  relate  damage  to  lost  production.  One  way  is  to  prune  leaves  to  simulate  beetle   attack  and  compare  nut  yields  on  healthy  palms.  Using  the  relationship  between  damage  and   yield  calculated  elsewhere,  work  in  Samoa  showed  that  a  25%  reduction  in  leaf  area  resulted  in   a  25%  reduction  in  nut  yield.  Indirect  damage  also  occurs.  In  Asia  and  parts  of  Papua  New   Guinea,  Oryctes  attack  encourages  invasion  by  Rhynchophorus  sp.  palm  weevils.  

Biology and  Life  Cycle   Oval  eggs  (3.5  x  4  mm)  are  laid  one  at  a  time,  5-­‐15  cm,  below  the  surface  of  moist  organic   materials,  such  as  sawdust,  manure,  compost  and  garbage  heaps,  or  above  ground  in  tunnels,   debris  in  axils  of  coconut  fronds,  in  still-­‐standing  but  dead  and  rotten  coconut  palms,  or  in  the   rotten  ends  of  fallen  coconut  trunks.  Logs  and  stumps  of  many  other  kinds  of  trees  are  also   hosts.  The  eggs  hatch  in  8-­‐12  days,  and  the  C-­‐shaped  larvae  or  grubs  are  white  then  creamy   1 Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control: Pacific Prospects. Inkata Press. 2 Photos of adult Oryctes and coconut damage (Mark Schmaedick, Entomologist, Land Grant Program, American Samoa Community College, Pago Pago.

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   with  brown  heads.  There  are  three  stages  lasting  80  to  200  days  (depending  on  quality  of  the   diet),  with  the  third  stage  up  to  100  mm  long  and  20  mm  diameter.  It  makes  a  hollow  where  it   feeds,  lining  it  with  liquid  faecal  material,  and  then  pupates  for  25-­‐40  days.     Adults  remain  in  the  ground  for  2-­‐3  weeks  and  then  chew  their  way  out.  They  are  brown  black,   shiny,  with  horns;  the  horn  of  the  male  is  larger.  Females  live  about  9  months,  and  lay  about   50  eggs;  males  live  about  5  months.  The  beetles  are  nocturnal,  flying  to  the  tops  of  coconuts   where  they  use  their  mandibles,  horn  and  strong  forelegs  to  tunnel  into  the  crown.  They  do   not  eat  the  frass  from  the  tunnels;  but  they  do  drink  the  sap  that  comes  from  tunnelling.    

Detection and  Inspection   Look  for  large  jet-­‐black  beetles  up  to  50  mm  long  and  23  mm  wide,  with  prominent  horns.   Look  for  tunnels  in  the  crown  with  frass  –  often  more  than  one  per  palm.  Look  for  the  V-­‐shape   damaged  fronds.  Use  a  hooked  wire  inserted  into  the  tunnel  to  remove  the  beetle.    

Management The  key  agent  is  a  virus  (Oryctes  rhinoceros  nudivirus)  originally  from  Malaysia  and,  more   lately,  a  fungus,  Metarhizium  anisopliae,  from  the  Philippines.  Apply  control  measures  if  3-­‐5   beetles  occur  per  ha  up  to  2  years  after  planting,  and  15-­‐20  beetles  per  ha  thereafter.  

QUARANTINE Vigilance  is  needed  at  seaports  and  airports  against  hitchhiking  beetles.  Also,  inspect  regularly   coconut  palms  growing  nearby  for  frass  and  leaf  symptoms.  The  FAO/IBPGR  Technical   Guidelines  for  the  Safe  Movement  of  Coconut  Germplasm  should  be  followed  when  imports  of   coconuts  are  made  (see,  http://pdf.usaid.gov/pdf_docs/PNACH919.pdf).    

NATURAL ENEMIES   There  are  many  general  predators  (pigs,  rats,  ants  and  other  insects)  and  scoliid  wasp  parasites   (e.g.  Scolia  ruficornis).  The  nudivirus  infects  larvae  and  adults.  It  was  released  in  Fiji,  Samoa   and  Tonga  in  the  late  ‘60s  and  early  ‘70s.  Adult  beetles  are  dipped  in  a  suspension  of  ground   infected  grubs,  and  then  released  to  infect  grubs  in  breeding  sites,  and  adults  in  feedings   tunnels.  In  Guam,  spores  of  M.  anisopliae  (imported  from  the  Philippines)  are  dusted  onto   beetles,  which  then  contaminate  larvae,  and  other  beetles  in  breeding  sites.  

CULTURAL CONTROL   •

• •

Destroy fallen  dead  palms  (split  open,  allow  to  dry  and  burn);  compost  dead  leaves  and   grass;  and  turn  manure  and  sawdust  heaps  regularly  and  remove  the  grubs.  Treat  compost   and  maure  with  Metarhizium  or  insecticides.  Note,  in  Samoa,  the  cutting  of  recently  dead   trunks  has  been  questioned  as  a  policy:  the  standing  dead  palms  are  a)  a  valuable  source   of  Oryctes  rhinoceros  nudivirus,  and  b)  can  be  processed  for  fence  posts,  and  other  uses.   Grow  a  legume  ground  cover  (e.g.  Pueraria  phaseoloides  or  Mucania  pruriens)  over  logs  or   stumps,  and  other  potential  breeding  sites  that  cannot  be  destroyed.   Use  a  hooked  wire  to  extract  and  destroy  adult  beetles  feeding  in  palm  crowns.  

CHEMICAL CONTROL   Chemical  control  is  uneconomical  because  of  the  low  value  of  coconuts  per  unit  area;   additionally  it  is  impractical  to  apply  insecticides  except  to  young  palms.  If  insecticides  are   needed,  use  lambda  cyhalothrin  or  cypermethrin.  Traps  with  the  attractant  ethyl-­‐4-­‐ methyloctanoate  have  been  used  to  monitor  populations  and  to  give  economic  control  in   some  countries.  Use  one  trap  per  2  ha.     AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Banana Weevil    

Extension Fact  Sheet  

109

Common  names:  Banana  weevil,  Banana  weevil  borer,  Banana  root  borer   Scientific  name:  Cosmopolites  sordidus.   Hosts:  Banana,  including  all  dessert  and  cooking  types,  and  Manila  hemp  (Musa  textilis).   Distribution:  All  banana-­‐growing  areas  of  the  world.  It  is  present  in  Fiji,  Samoa,  Solomon   Islands  and  Tonga.  Probably  native  to  Indonesia  and  Malaysia.      

Damage The  grubs  or  larvae  do  the  damage.  They  bore  into  the  corm  below  grown  to  feed,  and  this   tunnelling:  a)  causes  rots,  and  stops  the  flow  of  nutrients  to  the  leaves  so  that  they  appear   unhealthy  and  die  prematurely;  b)  weakens  the  plants  so  they  are  easily  blown  over;  c)  leads   to  suckers  withering  and  dying;  and  d)  produces  small  bunches  of  undersize  fruit.  It  is  often   difficult  to  tell  if  the  weevil  is  the  cause  of  poor  growth  or  if  it  is  poor  nutrition,  or  nematodes   attacking  the  roots  (see  Fact  Sheet  no.  08).  In  Samoa,  the  weevil  is  a  serious  pest  in  some   areas  only.  In  Fiji  and  Australia,  yield  losses  are  more  likely  in  poorly  maintained  plantations.      

Biology and  Life  Cycle   Eggs  are  oval,  about  2  mm  long,  and  1-­‐3  are  laid  a  week.  They  are  laid  singly  in  pits  chewed   between  leaf  scars  on  the  corms  near  or  just  above  ground  level.  They  are  also  laid  on  plants   blown  over  in  the  wind,  where  the  corm  and  leaves  meet,  and  on  the  side  facing  the  soil.  The   eggs  are  hard  to  find  as  they  become  covered  in  plant  sap.  Eggs  hatch  in  5-­‐7  days,  and  the   stout,  legless  grubs  are  creamy-­‐white  with  reddish-­‐brown  heads.  After  20  days  of  tunnelling   through  the  corms  they  are  fully-­‐grown.  They  then  make  oval  chambers  near  the  corm  surface   and  pupate.  Eight  days  later,  adults  emerge.  They  are  reddish  brown  at  first,  later  black,  about   12  mm  long,  with  a  typical  weevil  snout  (photo1).  In  Fiji,  the  life  cycle  is  about  50  days.     The  adults  have  well-­‐developed  wings,  but  rarely  fly,  and  when  disturbed  pretend  they  are   dead.  During  the  day  they  hide  under  debris  or  in  the  soil  around  banana  plants;  at  night  they   walk  short  distances  over  soil  and  vegetation.  Spread  is  mostly  in  infested  planting  material   not  by  other  means.  The  weevils  live  up  to  2  years.     1 Photo of adult Cosmopolites (Gerald McCormak, Cook Island Biodiversity & Natural Heritage: http://cookislands.bishopmuseum.org/)

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  larvae  and  their  tunnels  in  the  corms  just  above  ground  level.  Cut  discs  (10  cm  thick)   from  freshly  harvested  banana  stems  and  put  out  about  50  discs  per  ha  within  a  plantation,   placing  each  on  the  soil  at  the  base  of  a  banana  stool,  and  covered  with  leaves  to  prevent   drying  out.  After  5  days,  count  the  number  of  weevils  on  the  discs.  An  average  of  four  weevils   per  disc  indicates  treatment  is  required.  

Management QUARANTINE   In  countries  where  the  weevil  is  already  established,  planting  material  should  be  carefully   checked  before  it  is  used  to  established  new  plantations  (see  below).  Those  countries  yet  free   from  the  weevil  should  follow  the  FAO/IPGRI  Technical  Guidelines  for  the  Safe  Movement  of   Germplasm:  Musa  spp.,  which  recommends  importations  as  virus-­‐indexed  tissue  cultures  (see,   http://www.bioversityinternational.org/publications/search/results.html).  

NATURAL ENEMIES   Early  last  century  entomologists  from  Fiji  went  to  Indonesia,  the  presumed  origin  of  C.   sordidus,  and  found  several  beetles  preying  on  the  weevil.  The  most  important  was  a  histerid   beetle,  Plaesius  javanus.  This  beetle  was  introduced  into  Fiji,  along  with  another  histerid,  P.   laevigatus,  which  looks  similar.  P.  javanus  is  also  established  in  Samoa,  and  many  other  Pacific   island  countries,  but  not  Tonga.  The  larvae  and  adults  of  P.  javanus  attack  both  grubs  and   pupae  of  C.  sordidus.    In  Fiji,  it  appears  to  have  reduced  the  damage  done  by  the  weevil,  but   this  needs  to  be  confirmed.  The  ant,  Tetramorium  bicarinatumI,  is  reported  to  control  the   weevil  in  Cuba,  but  its  effect  in  Papua  New  Guinea,  and  elsewhere  in  the  Pacific,  is  not  known.  

CULTURAL CONTROL   Cultural  practices  are  important  in  preventing  outbreaks  of  this  insect.  Do  the  following:     • •

• • • •

Ideally, use  tissue-­‐cultured  plants  to  establish  new  plantings.   If  tissue-­‐cultured  plants  are  not  available,  use  suckers  for  planting  that  are  free  of  the   weevil.  Examine  the  planting  material  carefully,  taking  slices  from  the  corms  to  check  for   larvae,  pupae  and  tunnels.  If  any  of  these  are  found,  reject  the  source  of  planting  material.   Do  not  replant  weevil-­‐infested  areas  while  old  corms  are  still  in  the  ground.  Remove  the   old  corms  and  leave  land  fallow  for  at  least  3  months  (preferably  longer)  before  replanting.   When  plants  fall  over,  or  have  been  harvested,  cut  stems  into  60  cm  pieces,  and  then   lengthwise,  so  that  they  dry  out  rapidly  and  do  not  become  weevil  breeding  sites.   Remove  weeds  and  trash  from  around  banana  stools,  especially  if  management  includes   weevil  monitoring  (see  above)  and  insecticide  applications.   Note,  hot  water  (54°C  for  20)  for  nematode  control  in  corms  is  also  likely  to  destroy  weevil   eggs  and  grubs.  

CHEMICAL CONTROL   There  are  several  insecticides  in  different  groups  that  are  registered  for  use  by  the  Australian   Pesticides  and  Veterinary  Medicines  Authority,  and  they  can  be  found  at  www.apvma.com.au.   Do  not  use  insecticides  from  the  same  group  for  more  than  one  year.  Examples  of  those   chemicals  registered  include  oxamyl,  chlorpyrifos,  fipronil,  bifenthrin  and  imidacloprid.  An   aggregation  pheromone  (sordidin)  that  attracts  both  sexes  is  available  and  used  for  monitoring   (4  traps/ha)  and  mass  trapping  (20  traps/ha).     AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Leafminers  

Extension Fact  Sheet  

110

Common  name:  Leafminers   Scientific  names:  Liriomyza  sativae1  (vegetable  leafminer),  L.  trifolii  (chrysanthemum   leafminer),  L.  huidobrebsis  (serpentine  leafminer).   Hosts:  Many:  members  of  the  Cucurbitaceae,  Fabaceae,  Solanaceae,  Brassicaceae,  and  many   plants  in  the  cut  flower  trade.   Distribution:  Worldwide:  in  the  Pacific  region  L.  sativae  is  known  from  Samoa,  and  L.  trifolii   from  Samoa  and  Tonga.  Note,  L.  huidobrensis  is  unknown  in  Pacific  islands  apart  from  Hawaii.      

Damage The  host  species  attacked  by  L.  sativae  in  Samoa  are  not  recorded  by  Waterhouse  and  Norris1.   By  contrast,  beans  are  reported  to  be  attacked  by  L.  trifolii  in  Samoa;  and  beans,  cabbage,   celery,  Chinese  cabbage,  pigeon  pea,  tomato  (photo,  left2)  and  watermelon  by  L.  trifollii,  in   Tonga.  Female  feeding  punctures  damage  the  leaves  and  petioles  affecting  photosynthesis  and   causing  water  loss.  In  addition,  the  larvae  mine  (tunnel)  inside  the  leaves.  When  the  mines   occur  in  the  leaves  of  bean,  capsicum  and  cucurbit  seedlings,  for  instance,  this  can  set  back   their  growth.  It  may  result  in  the  leaves  drying  up  and  falling  early.  Leaf  fall  in  tomato  exposes   the  fruit  to  sunlight  and  may  result  in  sunburn.       Indirect  damage  also  occurs.  L.  sativae  transmits  virus  diseases  of  celery  and  watermelon.   However,  damage  through  virus  transmission  is  probably  not  as  important  as  that  of  mining  by   the  larvae  or  the  adults  feeding  on  the  leaves.    

Biology and  Life  Cycle   The  adult  is  a  black  and  yellow  fly  up  to  2.3  mm  long,  depending  on  the  species  (photo,  L.   trifolii2).  The  females  are  larger  than  the  males.  Females  feed  on  sap  from  leaves,  making  holes   with  their  ovipositors,  the  tubes  used  for  egg  laying;  and  both  sexes  take  nectar  from  flowers.   Eggs  are  laid  just  beneath  the  leaf  surface,  beginning  a  day  or  so  after  the  adults  emerge,  and   continuing  for  several  weeks.  The  eggs  hatch  after  a  few  days  and  the  larvae  or  maggots  mine   the  leaves.  The  maggots  are  colourless  at  first,  becoming  green  and  then  yellow  as  they   1

Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press. 2 Dr.J.Poorani, National Bureau of Agriculturally Important Insects (formerly PDBC), Bangalore, Karnataka, India. AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   mature;  they  are  up  to  3  mm  long.  During  their  life,  they  go  through  three  changes  and  then   leave  the  mines,  falling  to  the  soil  where  they  burrow  into  it  for  a  few  centimetres  to  pupate.   The  life  cycle  takes  from  less  than  3  to  more  than  9  weeks  depending  on  the  temperature  and   the  host.  At  30°C,  L.  sativae  takes  15  days  from  egg  to  adult.  

Detection and  Inspection   Look  for  feeding  punctures,  which  appear  as  white  speckles  about  0.15  mm  in  diameter.     Egg  laying  punctures  are  smaller  (0.05  mm)  and  round.  Look  for  white  mines  or  tunnels   snaking  over  the  leaf;  they  may  have  faeces  inside.  The  mines  increase  in  width  as  the  maggots   mature.    

Management QUARANTINE   Not  all  these  species  are  present  in  each  of  the  project  countries,  Fiji,  Samoa,  Solomon  Islands   and  Tonga.  That  being  the  case,  it  is  necessary  to  prevent  these  leafminers  from  extending   their  range.  In  particular,  quarantine  authorities  need  to  be  alert  to  the  fact  that  movement   across  national  borders  is  associated  with  the  trade  in  nursery  plants  and  cut  flowers.    L.   sativae  is  listed  as  an  A1  quarantine  pest  by  EPPO,  the  European  Plant  Protection  Organisation.  

NATURAL ENEMIES   There  are  a  large  number  of  natural  enemies  of  leafminers,  which  under  most  situations   provide  effective  control.  However,  many  of  them  have  proved  to  be  more  susceptible  to   insecticides  than  leafminers.  Consequently,  when  resistant  strains  of  leafminers  developed  in   response  to  over  use  of  insecticides  natural  enemies  are  insufficient  to  control  them.  The   strategy,  therefore,  is  to  preserve  natural  enemies  by  monitoring  leafminer  numbers,  knowing   the  numbers  likely  to  cause  damage,  and  by  careful  choice  and  timing  of  insecticides.       The  first  step  in  any  biological  control  program  in  a  Pacific  country  with  a  Liriomyza  problem  is   to  find  out  the  control  that  parasites  can  give  in  the  absence  of  insecticides.  Then  introduce   parasites  which  are  not  present.  A  number  of  parasites,  mainly  minute  species  of  wasps,  are   thought  to  have  particular  promise,  these  are:  Chrysocharis  parksii,  Chrysonotomyia   punctiventris,  Diglyphus  begini,  D.  intermedius  and  Ganaspidium  hunteri.       Note  that  Ganaspidium  utilis  and  Chrysocharis  oscinidus  have  been  introduced  to  Tonga  with   good  results.  

CULTURAL CONTROL   Cultural  practices  are  important  in  preventing  outbreaks  of  leafminers.  Do  the  following:     • •

Remove or  destroy  crop  residues  by  incorporating  them  into  the  soil.   Remove  weeds  as  these  serve  as  a  reservoir  for  leafminers.  

CHEMICAL CONTROL   Natural  enemies  play  an  important  role  in  limiting  leafminer  populations;  therefore,  pesticides   should  be  chosen  and  applied  with  care,  as  indiscriminate  use  may  worsen  the  situation  by   disrupting  natural  control.  Some  insecticides,  particularly,  pyrethoids,  are  effective,  but  there   are  strains  of  Liriomyza  species  that  have  become  resistant  to  them.    Abamectin,  the  growth   regulator  cyromazine,  and  spinosad  provide  control  against  larvae.     AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Coconut Spike  Moth    

Extension Fact  Sheet  

111

Common  names:  Coconut  spike  moth,  Oil  palm  bunch  moth   Scientific  name:  Tirathaba  rufivena1,  but  probably  at  least  three  species  exist.   Hosts:  Coconut  and  oil  palm,  although  also  reported  on  other  palms,  including  betel  nut  and   nipa,  and  on  banana.   Distribution:  Southeast  Asia  and  Oceania.  It  occurs  widely  among  Pacific  island  countries,   including  Fiji,  Samoa,  Solomon  Islands  and  Tonga.    

Damage Caterpillars  of  the  moth  feed  on  recently  opened  male  flowers,  and  bore  into  the  female   flowers  or  ‘buttons’  and  eat  out  the  contents.  However,  there  are  differences  of  opinion   among  scientists  whether  or  not  Tirathaba  causes  economic  loss.  It  is  complicated  because  of   two  facts:  a)  coconuts  naturally  shed  about  50%  of  the  nutlets  formed,  so  unless  the  caterpillar   attack  is  very  high,  and  less  than  4-­‐5  nuts  are  left  to  mature,  the  damage  caused  by  Tirathaba   is  likely  to  be  small;  and  b)  if  damage  to  one  spike  (the  fruiting  branch  that  has  male  and   female  flowers)  is  high,  the  rate  of  nut  shedding  on  the  next  one  may  be  low,  i.e.   compensation  occurs.       In  Fiji,  it  is  reported  that  Tirathaba  destroys  more  than  20%  of  the  nuts  on  a  spike,  and  if  this   were  prevented,  yields  would  increase  by  more  than  30%.  However,  no  evidence  has  been   given  to  support  this,  and  other  scientists  working  there,  and  in  Malaysia,  think  the  moth  has   no  affect  on  nut  production.  The  damaged  nuts  drop  first  and  then  some  of  the  undamaged   ones  until  a  number  is  reached  that  the  palm  can  sustain  to  maturity.  Furthermore,   calculations  suggest  that  caterpillars  would  have  to  damage  nearly  60%  of  the  nuts  before  they   reduced  the  yield,  whereas  mostly  they  damage  about  10%.     In  Tonga,  it  was  once  thought  that  Tirathaba  was  an  important  cause  of  low  yield,  but  this  is   no  longer  the  case  after  experiments  done  in  the  1980s.     1

Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press.

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   Contrary  to  the  above,  work  on  young  palms  in  the  Philippines  suggests  that  100%  damage  of   the  female  flowers  of  young  (3  to  5-­‐year-­‐old)  hybrid  palms  of  the  variety  MAWA  (Malayan   Dwarf  x  West  African  Tall)  can  occur.  The  reason  given  is  that  the  compact  leaves  of  the  crown   cause  the  flowers  to  be  constricted  as  they  open  creating  ideal  conditions  for  the  moth.    

Biology and  Life  Cycle   Eggs  are  laid  singly  or  in  small  groups  at  the  base  of  the  flower  spike  and  leaf.  They  hatch  in   about  6  days  and  go  through  five  stages  over  the  next  month  or  so.  The  caterpillars  are   brownish-­‐grey  with  dark  brown  heads.  Fully-­‐grown  caterpillars  may  reach  30  mm.  Early  stages   feed  on  the  male  flowers;  later  stages  bore  into  the  female  flowers  causing  them  to  drop   either  to  the  ground  or  into  the  leaf  base  where  silk  webs  from  the  caterpillars  bind  the  frass,   faeces  and  parts  of  the  flowers  into  a  mass  of  decaying  matter.  Pupation  occurs  in  a  cocoon   formed  by  this  debris;  the  pupae  are  found  in  the  leaf  bases  or  hanging  from  them.  After  1  to  2   weeks,  the  adults  emerge,  mate,  and  then  the  females  lay  up  to  250  eggs.  They  have  brown   narrow  forewings  (photo2),  and  broad  light  yellow  hindwings.  They  live  for  up  to  10  days.      

Detection and  Inspection   Look  for  young  nuts  that  have  been  bored,  and  look  for  caterpillars  amongst  frass,  silken   threads,  and  decaying  debris,  at  the  base  of  the  leaves.  Cocoons  containing  the  caterpillars   occur  among  the  leaves.  

Management Waterhouse  and  Norris1  say:  “From  the  experimental  evidence  from  Malaysia  and  Tonga,  it  is   difficult  to  escape  the  conclusion  that  T.  rufivena  has  very  little,  if  any,  effect  on  coconut   production,  despite  its  conspicuous  damage  to  both  male  and  female  coconut  flowers.  In  other   words  it  is  not  a  pest”.    

NATURAL ENEMIES   Four  parasites  from  Java  have  been  established  in  Fiji,  and  Waterhouse  and  Norris1  state:   “have  probably  lowered  T.  rufivena  abundance  there”.    These  are  Apanteles  tirathabae,   Telenomus  tirathabae,  Argyrophylax  basifulva  and  Venturia  palmaris.  Attempts  to  established   parasites  in  Samoa  and  Tonga  have  been  unsuccessful.    

CULTURAL CONTROL   None  known  

RESISTANT VARIETIES   None  known,  but  from  the  work  from  the  Philippines  reported  above,  hybrids  may  suffer   greater  damage  from  the  feeding  of  the  caterpillars  because  of  the  way  the  flower  opens   creating  ideal  conditions  for  the  caterpillars.  

CHEMICAL CONTROL   There  are  three  reasons  why  chemical  control  is  not  an  option:  first,  it  would  be  uneconomic   because  of  the  low  value  of  coconuts  per  unit  area;  secondly,  natural  enemies  play  an   important  role  in  limiting  coconut  spike  moth  populations  and  applications  of  insecticides  are   likely  to  do  more  damage  to  parasitoid  populations  than  those  of  Tirathaba;  and  thirdly,  there   is  evidence  that  Tirathaba,  is  not  a  pest,  except,  perhaps,  in  young  hybrid  coconuts.   2

Photo of adult Tirathaba (Gerald McCormak, Cook Island Biodiversity & Natural Heritage: http://cookislands.bishopmuseum.org/)

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Corn Earworm    

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Common  names:  Corn  earworm,  Cotton  bollworm,  Tomato  grub,  Tobacco  budworm   Scientific  name:  Helicoverpa  armigera1,  previously  Heliothis  armigera.   Hosts:  Wide,  but  especially  cotton,  beans,  maize  and  sorghum,  and  to  a  lesser  extent  tobacco,   tomato,  legumes,  and  many  weeds.   Distribution:  Worldwide,  including  Fiji,  Samoa,  Solomon  Islands  and  Tonga.    

Damage The  caterpillars  do  the  damage.  The  young  caterpillars  feed  only  on  leaves;  later,  when  they   reach  the  third  stage  in  their  development  they  feed  on  flower  buds  and  fruits,  boring  holes  in   them  in  the  process  (Photo2).  Damaged  fruits  are  then  invaded  by  fungi  and  bacteria  causing   rots  and  the  fruits  to  fall.  Indirect  damage  occurs  in  maize;  damage  to  the  tip  of  the  cob  allows   weevils  to  invade.  In  Fiji,  sorghum,  tomato,  maize  and  okra  are  the  most  important  crops   damaged  by  H.  armigera.  

Biology and  Life  Cycle   The  eggs  are  ribbed,  about  0.5  mm  diameter,  laid  singly  on  leaves,  buds,  flowers  and  young   fruit;  they  are  white  at  first  then  greenish-­‐yellow,  and  dark  brown  before  hatching.  The  newly   hatched  larvae  are  translucent  and  whitish  in  colour,  but  the  later  stages  –  there  are  usually  six   –  are  variable  in  colour,  ranging  from  greenish  and  yellow  to  red-­‐brown  with  three  dark  stripes   along  the  back  and  a  yellow  stripe  on  the  sides  (Photo).  The  length  of  the  larval  stage  is   affected  by  temperature,  and  also  the  food  eaten,  but  14-­‐18  days  is  likely  in  most  Pacific  island   countries.  When  mature,  the  caterpillars  are  up  to  40  mm  long.  The  mature  caterpillars  drop   to  the  ground,  burrow  into  the  soil  for  up  to  10  cm  and  form  a  cell  in  which  the  pupa  develops.   About  2  weeks  later,  the  adults  emerge;  mate  and  the  females  start  laying  eggs  –  about  a   thousand  in  a  lifetime  of  2  weeks.  The  adults  have  brown  forewings  with  a  single  dark  spot.  

1

Much  of  the  information  given  here  comes  from  Waterhouse  DF,  Norris  KR  (1987)  Biological  Control  Pacific   Prospects.  Inkata  Press.     2  Photo  of  corn  earworm  caterpillar,  Helicoverpa  armigera  (Pita  Tikai,  ACIAR  PC/2010/090,  Solomon  Islands)   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   Hind  wings  are  generally  lighter  with  a  wide  brown  border  at  the  wing  tips,  and  brown  veins.   The  entire  life  cycle  last  about  30  days.     Note  that  development  can  take  place  on  weeds,  and  from  these  the  larvae  migrate  to  crops  if   they  are  nearby.    

Detection and  Inspection   Look  for  the  caterpillars  on  the  leaves  or  hidden  in  the  fruits;  look  for  frass  or  faeces,  or  cut   open  buds  or  fruits  to  find  the  pest.  

Management The  Corn  earworm  is  a  difficult  pest  to  control  because  it  has  a  wide  host  range,  is  migratory   and  has  a  relatively  short  life  cycle.  The  difficulty  is  made  worse  because  of  its  ability  to   develop  resistance  to  insecticides.  Recent  strategies  include  area-­‐wide  management  and  IPM,   but  neither  has  been  developed  for  crops  grown  in  Pacific  island  countries.  

NATURAL ENEMIES   Many  parasites  and  predators  (bugs,  beetles,  spiders,  lacewings  and  ants)  attack  H.  armiger   worldwide,  but  none  are  specific  to  that  pest.  In  the  Pacific,  little  is  known  about  natural   enemies.  Interestingly,  it  is  an  unimportant  pest  in  Samoa,  unlike  the  situation  in  Fiji,  Solomon   Islands  and  Tonga,  where  it  is  considered  of  great  importance.     A  number  of  introductions  for  biological  control  of  H.  armigera  have  been  made  in  Fiji,   including  Cotesia  marginiventris.         In  general,  the  success  of  biological  control  of  the  pest  is  affected  by  its  migratory  habit,   meaning  that  when  large  numbers  of  egg-­‐laying  moths  invade  an  area,  the  resident  natural   enemies  are  likely  to  be  too  slow  to  respond  to  bring  the  numerous  larvae  under  control   before  significant  damage  has  occurred.    

CULTURAL CONTROL   Cultural  control  offers  only  limited  use  for  this  highly  mobile  pest,  although  weeding  and  the   removal  of  the  remains  of  crops  may  be  beneficial.  

RESISTANT VARIETIES   None  known  for  the  crops  of  interest  to  Pacific  island  countries,  although  resistance  is   reported  from  India  in  some  varieties  of  pigeon  pea,  peanut  and  chickpea.    

CHEMICAL CONTROL   To  be  effective,  scouting  for  eggs  and  young  larvae  is  required.  The  reason  for  this  is  that   insecticides  are  most  effective  against  the  early  larval  stages;  the  later  stages  burrow  into  plant   parts  and  are  more  difficult  to  treat.  If  synthetic  pyrethroids  are  used  it  is  important  that  they   are  alternated  with  those  from  a  different  chemical  group.    In  Australia,  for  instance,  H.   armigera  has  developed  a  resistance  to  a  wide  range  of  insecticides,  and  has  become  difficult   to  control.  

BIOPESTICIDES There  are  two  pathogens  of  H.  armigera  that  are  commercially  available,  although  not  widely   sold  in  Pacific  island  countries:  NVP,  nucleopolyhedrovirus,  and  Bt,  Bacillus  thuringiensis.  NVP   is  highly  selective  and  will  only  infect  H.  armigera  and  closely  related  species.   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Fruit Piercing  Moth    

Extension Fact  Sheet  

113

Common  name:  Fruit  piercing  moth   Scientific  name:  Eudocima  fullonia1,  previously  Othreis  fullonia.   Hosts:  A  wide  range  of  cultivated  and  wild  fruits,  including  banana,  citrus,  5-­‐corner  fruit,   guava,  mango,  passion  fruit,  pineapples,  and  in  outbreak  years,  capsicum,  melon  and  tomato.   Distribution:  Wide,  Asia,  Africa,  Oceania,  but  not  the  Americas.  An  important  pest  in  Fiji  and   Samoa,  less  important  in  Tonga,  and  present  but  unimportant  in  Solomon  Islands.    

Damage The  adult  (photo,  left2)  does  the  damage,  not  the  caterpillars.  The  moth  has  a  feeding  tube   (proboscis)  that  is  up  to  25  mm  long,  barbed  and  strong  enough  to  penetrate  tough  rind  of   fruits  and  to  suck  out  the  juices.  The  hole  then  becomes  an  entry  point  for  fungi,  and  rots   develop,  and  fruits  fall  (photo,  right).  Damaged  fruit  produce  a  smell  that  attracts  other  moths.       The  damage  caused  by  the  moth  fluctuates  greatly.  In  most  years,  the  percentage  of  damaged   fruit  is  small,  but  occasionally  there  are  serious  outbreaks,  usually  after  droughts,  when  citrus   and  tomatoes,  are  totally  destroyed.  In  Samoa,  losses  in  citrus  and  5-­‐corner  fruit  exceed  30%,   and  on  Viti  Levu,  Fiji,  losses  of  fruit  crops  (mainly  citrus)  are  10-­‐15%,  rising  to  90%  and  70%,   respectably  in  outbreak  years.  At  these  times,  loses  in  tomato  and  capsicum  are  also  high.    

Biology and  Life  Cycle   Eggs  are  laid  on  species  of  Erythina.  They  are  yellowish,  almost  round,  laid  singly  or  in  batches   of  several  hundred.  They  hatch  in  about  3  days,  and  go  through  five  stages  over  about  3   weeks.  The  caterpillars  are  dark  brown  to  black  when  together  in  large  numbers,  and  pale   yellow  to  green  when  solitary.  The  pupae  develop  in  silken  cocoons  on  leaves  that  they  drawn   together.  After  2-­‐3  weeks  the  adults  emerge,  mate  a  few  days  later,  and  the  female  starts   laying  eggs  –  up  to  750  -­‐  during  a  life  of  about  30  days.       Adult  are  about  5  cm  long  with  wingspans  up  to  10  cm.  The  body  is  brown  towards  the  front,   yellow-­‐brown  behind,  with  brown  forewings  flecked  with  green  and  white  (more  in  females),   and  orange  hind  wings  with  a  wide  black  comma-­‐like  mark,  and  a  black  border  (photo).   1

Much of the information given here comes from Waterhouse DF, Norris KR (1987) Biological Control Pacific Prospects. Inkata Press. Assistance was also given by Wilco Liebregts, Eco-consult Pacific, Fiji. 2 Photo of fruit piercing moth, Endocima fullonia (Gerald McCormack, Cook Islands Biodiversity & Natural Heritage: http://cookislands.bishopmuseum.org/). AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  the  adult  moths  after  sunset,  beginning  a  few  weeks  before  harvest.  Look  for  its  large   red-­‐glowing  eyes  in  torchlight.  Look  for  fruit  with  characteristic  small  holes;  often,  on  citrus,   wide  discoloured  rots  surrounding  the  holes,  and  fallen  fruit  (photo,  right).  

Management This  is  a  very  difficult  pest  to  control,  mainly  because  insecticides  cannot  be  applied  near  the   time  that  fruits  are  ripe,  adult  moths  are  not  attracted  to  light,  and  the  caterpillars  develop  on   trees  that  are  common  but  often  far  from  the  fruit-­‐growing  areas.  The  adult  moths  rest  on   weeds  near  the  food  source  during  the  day,  waiting  for  night,  again  making  them  difficult   targets  for  insecticide  programmes.  The  moths  are  strong  fliers.  

NATURAL ENEMIES   In  most  countries,  there  are  natural  enemies  of  Eudocima.  For  instance,  Trichogramma  nr.   papilionis  is  present  in  Fiji,  and  Trichogramma  sp.  and  Ooencyrtus  crassulus  are  endemic  to   Samoa.  However,  none  of  them  are  able  to  maintain  Eudocima  populations  below  economic   levels.  Furthermore,  severe  outbreaks  of  the  moth  occur  after  droughts.  When  droughts  occur   the  adult  moths  migrate  to  higher,  cooler  areas,  escaping  the  influence  of  natural  enemies,   and  these  suffer  a  decline  in  number.  When  rains  come  once  again,  and  host  trees  produce  a   flush  of  new  leaves,  the  remaining  moths  breed  rapidly  and  outbreaks  occur.       Several  attempts  have  been  made  in  Pacific  island  countries  to  introduce  natural  enemies  to   control  Eudocima.  From  New  Caledonia,  the  tachnid  fly,  Winthemia  caledoniae,  was   introduced  to  Fiji  and  Tonga,  and  Ooencyrtus  sp.  to  Samoa,  with  unknown  results.  By  contrast,   introduction  of  Telenomus  lucullus  from  Papua  New  Guinea  to  Samoa  in  1988  was  successful,   but  the  introduction  of  Ooencyrtus  sp.  was  not.  Other  potential  candidates  are  the  effective   egg  parasite,  Trichogramma  ostriniae,  reported  in  Hawaii,  and  Euplectrus  sp.,  a  larval   ectoparasitoid  from  India  introduced  into  Guam  in  2000.    

CULTURAL CONTROL   • •

Early harvest  is  a  possibility,  although  fruit  quality  suffers.     Bagging  of  fruit,  or  wrapping  in  newspaper,  is  also  a  possibility,  but  it  is  labour  intensive,   and  difficult  to  do  on  large  trees,  such  as  mango  and  breadfruit.  The  use  of  nets  is   effective,  but  it,  too,  is  expensive.  Like  fruit  wrapping,  nets  are  also  a  defence  against  birds   and  bats.   Removal  of  Erythrina,  because  it  is  the  host  of  the  caterpillars,  has  both  advantages  and   disadvantages:  there  may  be  reduction  in  damage  caused  by  the  moth,  especially  in   outbreak  years,  but  the  tree  provides  shade  for  cattle  and  crops,  living  fence  posts,  the   flowers  provide  food  for  bats,  and  in  some  places  they  have  cultural  significance.    

RESISTANT VARIETIES   None  known.    

CHEMICAL CONTROL   Not  effect  for  the  reasons  stated  above,  and  that  there  is  only  limited  contact  between  moth   and  fruit  when  feeding.  There  are  concerns,  too,  for  human  health,  because  applications  to   fruit  would  be  needed  near  the  time  of  harvest  to  be  effective.  

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Cabbage Webworm  

Extension Fact  Sheet  

114

Common  names:  Cabbage  webworm,  Cabbage  centre  grub,  Large  cabbage  moth   Scientific  name:  Hellula  undalis1.   Hosts:  Members  of  the  Brassicaceae  mostly,  i.e.  cabbage,  cauliflower,  Chinese  cabbage  and   radish.   Distribution:  Asia,  Africa,  Europe,  South  America  and  Oceania;  it  is  recorded  from  Fiji  and   Solomon  Islands.  Hellula  sp.  is  reported  from  Samoa.    

Damage The  caterpillars  do  the  damage.  Seedlings  are  destroyed  by  the  caterpillars.  On  older  plants,   the  young  larvae  make  mines  in  the  leaves  and  bore  into  the  stem;  later,  the  caterpillars   tunnel  into  the  heart  of  the  plant  destroying  the  bud  (photo,  left,  arrow)  and  causing  distorted,   stunted  leaves.  Frequently,  plants  have  several  small  clusters  of  leaves;  this  is  caused  by   damage  to  the  central  bud  and  the  development  of  others  (photo,  right).       The  Cabbage  webworm  is  said  to  be  an  important  pest  in  Solomon  Islands,  ranked  in  the  top   ten  of  the  insect  pests  of  the  country.  It  is  present  in  Fiji  and  said  to  be  important  locally,  but   not  reported  from  Tonga.  Hellula  sp.  (thought  to  be  H.  undalis)  is  present  in  Samoa,  but  its   importance  is  unknown.      

Biology and  Life  Cycle   The  eggs  are  oval,  except  they  are  flattened  where   attached.  At  first  they  are  white,  but  later  become   brownish-­‐red.  They  are  laid  singly  or  in  groups,  sometimes   in  chains.  After  about  3  days,  the  eggs  hatch.  Initially,  the   caterpillars  are  whitish-­‐yellow  with  dark  brown  to  black   heads,  but  when  mature,  after  five  development  stages,   they  are  greyish-­‐yellow  with  pinkish-­‐brown  longitudinal  stripes.  At  the  last  stage,  the   caterpillars  are  12-­‐15  mm  long  (photo,  left,  insert).       1 Much of the information given here comes from Waterhouse DF, Norris KR (1989) Biological Control Pacific Prospects – Supplement 1. ACIAR Monograph No. 12. Inprint Limited, Brisbane.

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   The  caterpillars  are  mostly  found  on  their  own,  feeding  within  the  stem  or  fleshy  parts  of  the   leaves.  The  caterpillar  stages  take  2-­‐3  weeks  to  complete,  with  slight  differences  depending  on   the  kinds  of  host  plants  upon  which  they  are  reared.  The  pale  brown  pupal  stage  occurs  just   below  the  soil  surface  in  a  cell  containing  a  cocoon  made  from  silk,  soil  particles  and  other   matter;  the  stage  lasts  1-­‐2  weeks  depending  on  the  temperature  and,  perhaps,  the  plants   upon  which  the  caterpillars  have  fed.  Sometimes  they  pupate  in  silk  in  folds  in  the  leaf.     The  forewings  of  the  adult  moth  are  greyish-­‐brown  with  wavy  lines  and  a  black  spot  (photo);   the  hindwings  are  grey,  darkening  at  the  margins.  The  wingspan  is  up  to  18  mm.  After   emergence,  the  moths  mate  and  the  females  lays  upward  of  150  eggs  over  the  next  3  to  10   days.  The  adult  moth  is  capable  of  flying  long  distances.  

Detection and  Inspection   Look  for  small  caterpillars,  with  dark  brown  or  black  heads,  up  to  15  mm  when  mature,  whitish   with  pinkish-­‐brown  longitudinal  stripes.  Look  for  the  caterpillars  at  the  apical  meristems  and   leaf  nodes.  Look  for  the  frass  (faecal  and  other  material)  at  these  places.  

Management This  is  a  difficult  pest  to  manage.  Part  of  the  problem  is  that  it  occurs  in  complexes  with  other   cabbage  pests,  particularly  Diamondback  moth  and  Cabbage-­‐heart  caterpillar.  The  use  of  an   insecticide  against  Cabbage  webworm  may  well  be  effective  for  this  insect,  but  less  so  against   other  pests,  and  in  the  process  destroy  their  natural  enemies.  The  other  problem  is  that  the   caterpillars  produce  webbing,  which  is  difficult  for  the  insecticides  to  penetrate,  and  also  the   caterpillars  are  protected  from  chemical  sprays  by  burrowing  into  the  centres  of  their  hosts.    

NATURAL ENEMIES   Compared  to  other  pests  of  cabbages,  little  work  has  been  done  on  the  natural  enemies  of  the   Cabbage  webworm.  In  many  countries,  including  Papua  New  Guinea  in  the  Pacific  island   region,  the  webworm  is  present,  but  is  not  a  serious  pest  so  further  studies  are  needed.    

CULTURAL CONTROL   • • • •

Check that  seedlings  taken  from  the  nursery  are  free  from  eggs  and  young  caterpillars.   Do  not  plant  new  brassica  crops  next  to  those  infested  with  the  Cabbage  webworm.       Keep  plot  of  cabbages  and  cauliflowers  free  from  weeds.   Handpick  larvae  and  eggs,  and  remove  infested  leaves.  

RESISTANT VARIETIES   Work  on  resistance  in  Chinese  cabbage  has  been  on-­‐going  at  AVRDC  (The  World  Vegetable   Center)  for  a  number  of  years.  

CHEMICAL CONTROL   The  problems  associated  with  the  use  of  insecticides  against  the  Cabbage  webworm  have  been   stated  above.  Trials  in  Samoa  reported  successful  management  of  the  pest  using  acephate,   permethrin  and  trichlorfon  at  8-­‐10  day  intervals.    

Weekly applications  of  neem  are  likely  to  be  effective.  Bt,  Bacillus  thurigiensis,  is   recommended,  and  if  used  should  be  applied  before  larvae  are  protected  by  their  silken  webs,   and  before  they  have  moved  into  the  centre  of  cabbages  and  cauliflowers  where  they  are   difficult  to  reach  by  biopesticides.   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Asian Corn  Borer  

Extension Fact  Sheet  

115

Common  names:  Asian  corn  borer,  Asian  corn  worm,  Oriental  corn  borer   Scientific  name:  Ostrinia  furnacalis1.   Hosts:  Maize,  including  sweet  corn,  ginger  and  sorghum  are  the  main  hosts,  but  also  found  on   capsicum  and  sugar  cane,  and  more  recently  a  pest  of  cotton.  It  is  recorded  on  maize  from   Solomon  Islands.   Distribution:  Widespread  in  Asia,  Southeast  Asia.  Limited  distribution  in  Oceania:  present  in   Solomon  Islands,  but  not  in  Fiji,  Samoa  or  Tonga.      

Damage The  caterpillars  can  cause  serious  yield  losses  in  corn.  They  bore  holes  into  the  stems  and  cobs,   and  feed  on  the  silk  as  well  as  the  kernels.  The  mature  caterpillars  commonly  feed  on  the  stalk.   Frass  is  seen  around  the  holes.  The  leaves  may  wilt  above  the  entry  holes.  

Biology and  Life  Cycle   Eggs  are  laid  in  groups  at  the  base  and  underside  of  leaves.  They  hatch  after  3-­‐4  days  and  the   caterpillars  go  through  five  stages.  The  caterpillars  are  pink-­‐brown  with  spots  on  the  back   (photo).  In  the  early  stages  the  caterpillars  feed  in  the  whirl  of  leaves,  but  as  they  grow  they   move  to  the  tassel  (the  male  flowers)  and  then  into  the  ear,  feeding  on  the  silk  (female   flowers)  and  kernels.  The  late  stages  bore  into  the  stalks  to  feed.  After  3-­‐4  weeks  of  feeding   the  caterpillars  form  pupae  within  the  stems;  this  stage  lasts  7-­‐9  days  before  the  moth   emerges.      

1

Much  of  the  information  in  this  fact  sheet  is  summarized  from  the  CABI  Crop  Protection  Compendium,   http://www.cabi.org/cpc/   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   The  female  moth  lays  up  to  1500  eggs.  The  female  is  pale  yellow  brown  with  irregular  bands   across  the  wings;  the  male  is  darker.  The  wingspan  is  20-­‐20  mm;  females  are  slightly  larger   than  males.  The  moth  is  a  strong  flyer.  

Detection and  Inspection   Look  for  plants  that  are  wilting.  Look  for  small  piles  of  frass  on  the  stems  or  cobs.  If  there  are   entry  holes,  open  the  stem  and  cob  (see  photo)  and  look  for  the  caterpillar.  

Management IPM  strategies  have  been  used  to  manage  this  pest,  especially  in  the  Philippines.  However,   they  are  complex,  and  better  suited  to  commercial  plantings.  They  involved  scouting  to  check   the  number  of  caterpillars  per  plant,  the  use  of  a  microbial  pesticide,  Bt  or  Baccillus   thuringiensis  subsp.  kurstaki,  release  of  predatory  earwigs,  the  use  of  moderately  resistant   varieties,  sanitation  and  chemical  pesticides.  

NATURAL ENEMIES   There  are  a  number  of  natural  enemies  of  Ostrinia  of  which  the  egg  parasitoids,  Trichogramma   species,  are  reported  to  be  the  most  efficient.  Within  the  Pacific  island  countries  they  are   reported  from  Guam,  Northern  Mariana  Islands  and  Papua  New  Guinea.  T.  chilonalis  is  the   most  important  parasitoid  in  Guam,  but  without  other  control  measures  it  cannot  keep  the   pest  below  economic  threshold  levels.  No  larval  or  pupal  parasites  have  been  found  that  help   to  control  populations  of  the  Asian  corn  borer.  

CULTURAL CONTROL   •

Remove the  tassels  from  75%  of  the  plants;  this  a)  removes  the  caterpillars  from  the  plants   and  b)  takes  away  pollen  that  would  otherwise  have  fed  the  caterpillars.  

RESISTANT VARIETIES   Work  on  resistant  varieties  has  been  carried  out  in  a  number  of  countries,  and  differences   exist.  Farmers  should  be  advised  to  test  different  varieties.  

CHEMICAL CONTROL   Synthetic  insecticides  are  not  recommended  as  they  interfere  with  the  parasitoids  that  control   O.  furnacalis.    

Biopesticides. Neem  (water  extracts  from  seed  kernels)  has  been  used  in  trials  in  Papua  New   Guinea  and  found  to  be  effective.  The  research  there  found  that  removing  the  tassels  from   75%  of  the  plants,  release  of  T.  plasseyensis,  an  endemic  species,  and  one  application  of  neem   gave  satisfactory  control  of  O.  furnacalis.      

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Coconut Termite  

Extension Fact  Sheet  

116

Common  names:  Coconut  termite,  Rainbow  termite   Scientific  name:  Neotermes  rainbowi1.   Hosts:  Coconuts  palms  mainly,  but  also  the  stilt  roots  of  Pandanus;  reports  that  it  attacks  other   trees  may  be  due  to  misidentifications.   Distribution:  Known  only  from  the  central  Pacific.  It  is  present  in  many  atoll  countries,  and   thought  to  be  present  in  Fiji  (Rotuma  group)  and  Tonga.  Note,  the  presence  of  N.  rainbow  in   Fiji  is  questioned  by  Waterhouse:  a)  citrus  and  cocoa  are  attacked  which  is  unusual,  and  b)  the   net-­‐like  grooves  in  the  bark  are  not  reported.    

Damage The  termites  (photo,  above2)  hollow  out  living  trunks  leading  to  the  top  of  the  palm  snapping   off,  even  in  the  relatively  low  force  of  the  tradewinds.  The  yield  of  young  palms  may  also  be   reduced,  and  they  may  be  killed  before  they  bear  coconuts.  The  termite  workers  make  holes   and  grooves  on  the  surface  of  the  trunk,  and  these  are  characteristic  of  N.  rainbowi  (photo,   below2),  and  unlike  other  species;  later,  these  form  a  net-­‐like  pattern  from  soil  level  to  several   metres.  The  grooves,  which  extend  to  the  depth  of  the  bark  are  covered  with  chips  of  wood   and  bark  mixed  with  faecal  matter.       The  insides  of  the  trunk  are  also  attacked,  and  the  hollowing  that  occurs  leads  to  the  loss  of   the  tops  of  the  palm.  The hollow tunnels are filled with faeces mixed with shredded bark and wood.  In  some  places,  the  termites  spread  through  roots  and  soil  to  neighbouring  palms.       In  communities  where  coconuts  have  high  social  and  economic  importance,  this  is  a  serious   pest.   1

Much of the information given here comes from Waterhouse DF (1993) Biological Control Pacific Prospects – Supplement 2. ACIAR Monograph No. 20. Brown Anderson, Burwood, Victoria. 2 Photos of soldier and worker (above), and grooves in bark (below) made by Neotermes rainbowi (Gerald McCormak, Cook Island Biodiversity & Natural Heritage: http://cookislands.bishopmuseum.org/) AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Biology and  Life  Cycle   Neotermes  species  are  classified  as  live-­‐wood  termites,  meaning  they  attack  living  trees.  They   are  considered  to  be  primitive  termites.  The  life  cycle  starts  with  a  nuptial  flight  and  a  male   and  female  establishing  a  colony  in  a  suitable  tree.  They  enter  the  tree  through  a  crack  or   wound,  or  by  chewing  their  way  in.  After  mating,  the  female  stats  laying  eggs,  which  mostly   become  workers,  and  a  few  soldiers  (photo,  above2).  The  young  termites  feed  and  tend  the   king  and  queen,  more  eggs  are  laid  and  the  colony  grows.  Colonies  may  last  for  more  than  20   years.  Kings  and  queens  can  be  replaced  from   immatures  should  they  be  injured  or  die.     The  function  of  the  grooves  (photo,  right2)  in  the   coconut  bark  is  not  known,  but  several  possibilities   are  suggested:  moisture  control,  temperature   regulation  or  conditioning  of  the  wood  beneath.    

Detection and  Inspection   Look  for  the  net-­‐like  grooves  covered  with  a  mix  of   wood  and  faecal  matter  within  the  bark  of   coconuts;  these  channels  are  characteristic  of  this   termite.  Look  for  hollowed  out  stumps.    

Management NATURAL  ENEMIES   There  are  many  natural  enemies,  including  ants  and  many  predatory  insects,  but  also  mites,   birds,  lizards,  snakes,  frogs,  fungi,  and  nematodes.  Mostly,  they  hasten  the  demise  of  already   weakened  colonies,  and  have  limited  potential  as  biological  control  agents.  Ants  are  probably   the  most  important  factor  preventing  the  spread  of  the  termite,  but  it  is  not  recommended   that  they  be  introduced  to  islands  infested  with  Neotermes  to  reduce  populations  or  even   eliminate  them.  Any  introduced  ants  are  more  than  likely  to  become  pest  later.  

CULTURAL CONTROL   •

Remove and  burn  infested  coconuts  palms  as  soon  as  the  telltale  net-­‐like  grooves  are  seen   on  the  bark.  

RESISTANT VARIETIES  

No coconut  varieties  are  known  to  be  resistant.  

CHEMICAL CONTROL   Insecticides  are  not  recommended  and  should  not  be  used,  especially  where  contamination  of   the  water  table  is  a  possibility;  arsenic,  lindane,  dieldren  and  others,  which  are  now  banned   worldwide,  have  been  used  in  the  past.     Biopesticides.  Selected  strains  of  Metarhizium  anisopliae  and  an  entomopathogenic  nematode,   Heterorhabditis  sp.  have  been  tried  in  Tuvalu  by  injecting  them  into  termite  nests,  and  have   given  promising  results.  

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Onion Thrips    

Extension Fact  Sheet  

117

Common names:  Onion  thrips,  Potato  thrips,  Tobacco  thrips   Scientific  name:  Thrips  tabaci1.   Hosts:  Wide;  onions  are  a  preferred  host,  but  infestations  also  occur  on  brassicas,  cucurbits,   legumes,  potato,  tobacco,  tomato  and  many  ornamentals.   Distribution:  Worldwide,  including  Fiji,  Solomon  Islands,  and  Tonga  where  it  is  locally  important.  

Damage The  adults  and  young  (larvae)  do  the  damage.  They  suck  out  the  contents  of  cells,  leaving  air-­‐ filled  spaces  beneath  the  surface,  giving  the  plants  a  silvery  (and  in  some  case  a  silvery-­‐bronze)   look  in  sunlight  (e.g.  capsicum,  cucumber  and  leeks).  The  feeding  produces  distorted  leaves  (e.g.   bronze  blisters  on  cabbage),  discolouration  (eg  capsicum  flowers),  withering  from  water  loss   (e.g.  onion)  and  death  (especially  seedlings  of  onion  and  cabbages).  Reduction  of  yields  is   common  and  death  of  entire  crops  can  occur.  In  the  USA,  50  adult  thrips  per  onion  plant  results   in  a  50  per  cent  loss  of  yield.     Tiny  black  faecal  specks  occur  on  leaves  and  flower  parts  and  make  plants  unattractive  to   consumers,  and  this  adds  to  the  economic  loss  to  growers.     Indirect  damage  occurs  as  the  thrips  spread  Tomato  spotted  wilt  virus,  a  serious  disease  of  many   vegetables,  especially  tomato,  capsicum  and  lettuce  (but  not  onions).  Weeds  serve  as  an   important  reservoir  for  the  virus.  Symptoms  are  purple-­‐brown  blotches  on  stems,  ring  patterns   and  blotches  with  haloes  on  leaves,  and  discoloured  flowers.  Young  stages  of  the  thrips  acquire   the  virus  within  15  minute  of  feeding  on  infected  plants,  and  a  few  days  later,  when  adult,  they   transmit  the  virus,  and  continue  doing  so  for  the  remainder  of  their  lives.    

Biology and  Life  Cycle   Thrips  are  parthenogenetic,  that  means  females  do  not  need  males  to  produce  fertile  eggs.  Eggs   are  white,  kidney-­‐shaped,  about  0.25  mm  long  and  012  mm  wide.  Males  occur,  but  they  are   rare.  The  eggs  are  placed  singly  in  slits  in  leaves  and  flowers.  They  hatch  in  2-­‐4  days,  and  the   1 Much of the information given here comes from Waterhouse DF, Norris KR (1989) Biological Control Pacific Prospects – Supplement 1. ACIAR Monograph No. 12. Inprint Limited, Brisbane.

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   larvae  (they  look  like  small  adults  without  wings)  are  yellow,  and  group  together  in  leaf  axils.  The   mouthparts  are  beak-­‐shaped  with  a  ‘tooth’  that  tears  the  surface  layers  and  a  tube  to  suck  up   the  sap  and  cell  pieces.     The  larvae  moult  once,  and  then  when  fully  formed  drop  to  the  soil  and  develop  into  pupae.  The   adults  emerge  a  few  days  later;  they  are  yellow  and  brown  with  red  eyes,  and  about  1.5  mm   long.  The  entire  life  cycle,  from  egg  to  adult  is  about  11  days  at  30°C.     Thrips  are  not  strong  fliers,  but  they  move  short  distances  (a  few  metres)  from  dying  weeds  to   crop  plants,  and  over  long  distances  (tens  or  hundreds  of  kilometres)  when  large  numbers  are   caught  in  warm  updrafts.  Spread  also  occurs  with  the  international  movement  of  traded  pot   plants  and  cut  flowers.  

Detection and  Inspection   Look  for  thrips  on  the  leaves  or  in  the  buds  and  flowers.  This  is  usually  done  by  shaking,  tapping   or  washing  the  plants.    

Management NATURAL  ENEMIES   Many  natural  enemies  of  T.  tabaci  have  been  reported,  but  few,  if  any,  are  specific  to  the  pest.   Predators  include  bugs,  beetles,  lacewings,  flies,  mites  and  predatory  thrips,  and  there  are   wasps  and  fungal  parasites.  Some  predators  consume  large  number  of  thrips  each  day,  but   many  also  feed  on  other  insects,  and  give  these  higher  priority.  IPM  programs  for  greenhouses   use  yellow  sticky  cards  for  scouting,  sanitation,  and  commercial  preparations  of  Verticilium   lecanii,  predatory  mites,  lacewings  and  strategic  use  of  insecticides.  

CULTURAL CONTROL   • • • •

• • • •

Do not  plant  the  same  crop  successively  on  the  same  land;  leave  a  break  of  2-­‐3  years.   Plant  new  crops  upwind  from  older  crops  where  thrips  occurred.   Apply  mulch  to  suppress  weeds,  for  lower  loss  of  soil  moisture,  and  increase  organic  matter.   Remove  weeds,  volunteer  plants  and  debris  of  the  previous  crop  to  prevent  thrips  surviving   and  spreading  to  new  crops.  Note  that  some  common  weeds,  e.g.  Emilia  sonchifolia,  can  be   a  reservoir  of  Tomato  spotted  wilt  virus.     Inspects  seedlings  transplanted  from  the  nursery  and  remove  those  infested.   Remove  plants  with  signs  of  Tomato  spotted  wilt  virus  as  soon  as  they  are  seen.   If  crops  are  grown  in  enclosures,  early  detection  of  thrips  is  important.  Use  yellow  sticky   cards  placed  just  above  the  crop  to  monitor  the  presence  of  thrips.   If  yellow  sticky  cards  are  not  available,  check  flowers  for  thrips  by  tapping  them  over  paper.  

RESISTANT VARIETIES  

White onion  varieties  are  more  tolerant  of  thrips  than  red.  There  are  varieties  of  tomato  and   capsicum  that  have  resistance  to  Tomato  spotted  wilt  virus.  

CHEMICAL CONTROL   Use  contact  insecticides,  e.g.  malathion,  lambda-­‐cyhalthrin  or  other  synthetic  pyrethroids,  or   systemic  products,  e.g.  fipronil  or  imidacloprid.  Note  that  insecticides  have  the  potential  to   reduce  predator  and  parasite  populations.  It  is  important  to  limit  the  number  of  applications  and   rotate  between  classes  of  insecticides  to  prevent  development  of  thrips  resistance.  By  contrast,   spinosad,  a  product  containing  a  soil  bacterium,  Saccharopolyspora  sponosa,  has  shown  promise   because  if  its  low  toxicity  to  beneficial  insects.  Neem  is  also  effective.   AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Coffee Berry  Borer  

Extension Fact  Sheet  

118

Common  name:  Coffee  berry  borer   Scientific  name:  Hypothenemus  hampei1.   Hosts:  Coffea  arabica,  Coffea  canephora.   Distribution:  Worldwide:  Asia,  Africa,  South  and  Central  America,  Caribbean,  and  the  Pacific.  It  is   present  in  Fiji,  where  it  is  one  of  the  top  10  pests.    

Damage The  adults  (photo,  right2)  feed  on  the  young  green  berries  and  this  allows  entry  of  decay   organisms,  and  the  berries  fall  prematurely.  Greater  damage  is  done  by  females  boring  into   mature  berries  and  breeding  inside  them  (photo,  left3).  The  damage  varies,  but  berries  can  be   completely  destroyed  by  the  adults  and  their  larvae  so  that  all  that  remains  is  frass  or  faeces.  It   is  not  uncommon  for  100%  of  the  berries  to  be  attacked  if  less  uncontrolled.  Further  damage   occurs  if  the  beans  are  not  properly  dried  before  being  stored.  Even  if  only  a  few  of  the  beans   are  infested,  the  damage  affects  quality,  and  the  beans  will  be  difficult  to  market.  

Biology and  Life  Cycle   The  fertilised  female  flies  to  the  ripening  berries  and  bores  into  them.  If  the  endosperm  is  still   soft  it  may  wait  in  the  fruit  for  it  to  become  firm,  or  visit  other  berries.  Eggs  are  about  0.6  mm   long,  and  are  laid  in  chambers  chewed  out  of  the  beans,  each  female  producing  30-­‐50  eggs  in  2-­‐ 7  weeks.  Eggs  hatch  within  a  week  or  so  and  the  larvae  start  eating  the  beans.    After  about  2   weeks  and  two  moults,  the  larvae  reach  maturity,  develop  into  pupae  and  4-­‐9  days  later  emerge   as  adults.  The  entire  life  cycle  is  about  4  weeks.     There  are  about  10  females  for  every  male.  Males  have  short  wings  and  do  not  fly;  they  remain   in  the  berries  for  the  3  months  of  their  lives.  Females  are  fertilised  a  few  days  before  they  leave   the  berries  to  find  other  berries  in  which  to  lay  their  eggs.  Some  females  remain  and  lay  eggs  in   the  same  berry.  Females  live  on  average  about  150  days,  much  longer  than  the  males.   1

Much of the information given here comes from Waterhouse DF, Norris KR (1989) Biological Control Pacific Prospects – Supplement 1. ACIAR Monograph No. 12. Inprint Limited, Brisbane. 2 Photo of adult of Hypothenemus hampei (Georg Goergen, IITA-Benin). 3 Photo from: Save Kona coffee! Fighting the coffee berrty borer (http://marcoinkona.com/2012/04/21/save-konacoffee-fighting-the-coffee-berry-borer/).

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   The  adults  are  black,  about  1.5  mm  long  by  0.4  mm  wide,  covered  in  short  stiff  hairs.  Other   noticeable  features  are  short  club-­‐shaped  antennae,  and  bristles  on  the  legs  that  are  used  for   tunnelling  through  the  coffee  berries.  The  females  can  fly  for  about  30  minutes;  they  also   swarm,  perhaps  using  updrafts  of  air  to  achieve  long-­‐distance  travel.  During  times  when  the   crop  is  low  or  non-­‐existent,  the  beetles  remain  inactive  in  dry  berries  or  those  on  the  ground.  

Detection and  Inspection   Look  for  holes  in  the  top  of  the  fruit.  Look  for  brown  frass  over  the  hole.  Cut  open  the  berry  and   find  the  female  in  tunnels  in  the  endosperm  (the  starch  deposit  in  the  seed).  Look  for  holes  in   beans  by  rubbing  them  between  the  hands  to  remove  the  parchment  (a  skin  over  the  seed).  

Management NATURAL  ENEMIES   Several  wasps  have  been  introduced  from  Africa  to  Central  and  South  America,  and  elsewhere,   but  without  noticeable  impact.  Ants,  predatory  beetles  and  nematodes  also  occur,  but  none  has   sufficient  potential  to  control  Hypothenemus  populations.  By  contrast,  80%  mortality  of  adults   occurs  with  the  fungus,  Beauvaria  bassiana,  in  countries  with  continuous  high  humidity.  

QUARANTINE It  is  important  that  seed  coffee  imported  into  countries  yet  free  from  the  beetle  is  treated   appropriately.  Fumigation  before  entry  and  inspections  should  be  mandatory.  

CULTURAL CONTROL   Recommendations  differ  depending  on  the  degree  of  control  by  parasitoids  and  the  need  to   preserve  them,  i.e.  stripping  berries  from  trees  affects  parasitoids  and  beetle  alike.   • •

• •

Pick berries  as  they  ripen.   Collect  blackened  berries  from  the  ground  or  bushes  -­‐  those  decayed  by  fungal  infections   and  beetles  -­‐  and  burn  them.  Alternatively,  do  the  following  for  3  months  to  break  life  cycle:     o Remove  all  berries  from  ground  and  bushes  after  harvest,  and  continually  remove   young  berries.   o Strip  all  berries  from  the  bushes.   Where  parasitoids  are  important  (consult  agricultural  research  or  extension  authorities):   o Pick  all  ripe  berries  at  least  every  2  weeks  (more  often,  if  practical).   o Leave  fallen  berries  as  reservoir  for  parasites  (where  numbers  fallen  are  low).   o Increase  shade  (there  may  be  more  predators  under  shade,  but  this  varies  locally).   Prune  bushes  after  harvest,  removing  branches  on  which  berries  are  too  high  to  reach.   Destroy  bushes  in  abandoned  plantations  as  they  are  sources  of  infestation.      

RESISTANT VARIETIES  

Differences exist  between  Coffea  species  and  between  varieties  of  C.  arabica  and  C.  canephora,   but  are  probably  not  sufficient  as  a  basis  for  developing  resistant  varieties.    

CHEMICAL CONTROL   Insecticides  are  effective  if  applied  early  when  the  female  is  in  the  entry  tunnel,  but  not  later   when  berries  are  mature  and  the  female  has  penetrated  the  endosperm.  Fallen  berries  are   particularly  difficult  to  treat.  Fenthion  and  pirimiphos  methyl  are  recommended.  (Note  that   endosulfan  previously  used  extensively  in  Central  and  South  America  is  banned  under  the   Stockholm  Convention,  April  2011.)  In  Hawaii,  a  commercial  preparation  of  Beauvaria  is  used.     AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Euscepes batatae    

Extension Fact  Sheet  

119

Common  name:  West  Indian  sweetpotato  weevil   Scientific  name:  Euscepes  batatae  (previously  E.  postfasciatus).   Hosts:  Sweetpotato  and  wild  relatives  in  the  genus  Ipomoea.   Distribution:  Widespread  in  the  Pacific  islands,  Caribbean,  Central  and  South  America,  and  with   a  restricted  distribution  in  the  USA  (California  and  Hawaii)  and  Asia  (Japan).  It  is  recorded  from   Fiji,  Samoa  and  Tonga.    

Damage   The  larvae  or  grubs  do  the  most  damage,  and  this  is  similar  to  that  caused  by  the  sweetpotato   weevil,  Cylas  formicarius.  The  larvae  tunnel  through  the  base  of  the  stem  (crown)  and  the   storage  roots.  In  the  storage  roots,  tunnelling  produces  chemicals  called  terpenes,  which  give   the  flesh  an  unpleasant  taste.  The  adults  also  feed  on  the  shoots  and  young  stems,  but  the   damage  is  low  compared  to  that  on  storage  roots  and  crown.  

Biology and  Life  Cycle   The  eggs  are  round,  yellowish,  laid  singly  in  pits  in  the  stems  (always  at  the  nodes,  the  junction   of  stems  and  petioles)  or  in  storage  roots.  After  laying  the  eggs  the  pits  are  sealed  with  a  faecal   plug.  Storage  roots  are  preferred  to  stems.  The  eggs  hatch  in  about  10  days,  and  the  legless   grubs  moult  four  times  over  the  next  20-­‐30  days,  reaching  a  length  of  about  8  mm.  The  pupae   are  white,  about  5  mm  long.  After  another  10  days  the  adults  emerge.  They  leave  the  storage   roots  and  stems  by  chewing  exist  holes.  Adults  are  3.5-­‐4  mm  long  and  1.5  mm  wide,  reddish   brown  to  greyish  black,  covered  with  stiff  hairs,  with  two  white  patches  on  the  wing  cases   (photos,  left  &  right1);  they  are  thought  to  live  about  6  months.     There  is  no  evidence  that  the  weevils  spread  by  flying.  It  is  more  likely  that  they  crawl  short   distances  from  weedy  borders,  and  are  spread  longer  distances  in  cuttings  and  in  storage  roots   used  for  planting.  Hot  and  dry  weather  favours  weevil  development.  At  27-­‐30°C,  the  life  cycle   takes  about  30  days.     1 Photo of adult Euscepes (Gerald McCormak, Cook Island Biodiversity & Natural Heritage: http://cookislands.bishopmuseum.org/)

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  at  the  base  of  the  vine  (called  the  crown)  for  small  holes  and  damage  to  the  stem.  Break   the  stem  to  look  for  tunnels,  rots  and  larvae.  Dig  up  a  storage  root  and  look  for  damage  to  the   skin,  and  feeding  tunnels  of  the  larvae  inside.  Detection  of  early  infestation  is  not  easy  as  adults   are  most  active  at  night,  and  they  pretend  to  be  dead  when  disturbed.    

Management NATURAL  ENEMIES   Little  is  known  about  natural  enemies.  Infections  from  the  fungus  Beauveria  sp.  are  reported   from  Peru  and  Japan.  However,  the  weevil  causes  greatest  damage  during  dry  weather,  so   strains  of  Beauveria  are  needed  that  persist  and  are  pathogenic  during  such  times.  In  Cuba,   nests  of  ants  (e.g.  Pheidole,  the  big-­‐headed  ant)  are  put  in  gardens  in  rolls  of  banana  leaves.  

QUARANTINE Trade  in  storage  roots  between  Pacific  island  countries  should  be  carefully  controlled,  and   germplasm  movements  should  follow  the  FAO/IBPGR  Technical  Guidelines:   http://www.bioversityinternational.org/fileadmin/bioversity/publications/pdfs/503_Sweet_Pot ato.pdf?cache=1363615831.  Note,  the  weevil  has  not  been  recorded  from  Solomon  Islands.  

CULTURAL CONTROL   Cultural  control  methods  offer  the  best  chance  of  reducing  populations  of  the  weevil  to   acceptable  levels.  Hygiene  measures  and  the  use  of  cuttings  free  from  adults  and  eggs  are  two   of  the  most  important  cultural  control  strategies:     • • • • • • •

Hygiene: Remove  and  destroy  infested  vines  and  storage  roots  immediately  after  harvest.   Choice  of  varieties:  Use  those  that  produce  an  early  crop.  Note  that  PT  (pathogen-­‐tested)   varieties  without  virus  infections  are  likely  to  give  early  and  high  yields.   Choice  of  cuttings:  Always  use  tip  cuttings  for  planting,  25-­‐30  cm  long,  from  young  shoots.   Harvest:  Ideally,  harvest  all  the  storage  roots  at  one  time.   Alternate  hosts:  Remove  wild  Ipomoea  species  from  around  the  field.   Hill-­‐up:  Cover  exposed  storage  roots  and  cracks  with  soil;  it  is  important  to  do  this.   Remember,  weevils  do  not  burrow;  they  reach  storage  roots  through  cracks  in  the  soil.   Crop  rotation:  Do  not  plant  sweetpotato  on  the  same  land  continuously;  rotate  with  other   crops  leaving  a  gap  of  at  least  3-­‐4  years  between  crop  of  sweetpotato  on  the  same  land.  

RESISTANT VARIETIES  

None have  been  reported,  although  germplasm  collections,  such  as  that  at  the  International   Potato  Center  (CIP),  Peru,  have  been  screened  for  resistance.    

CHEMICAL CONTROL   •

Before planting:  Treat  vine  cuttings  with  insecticide  (e.g.  bifenthrin)  to  kill  weevils  and   prevent  infestation  of  new  plantings.  Inspect  the  crop  regularly,  at  least  once  a  week:  check   the  base  of  the  vines,  looking  for  damage  and  holes.   After  planting:     o Spray  with  insecticide  (e.g.  bifenthrin,  fipronil,  chlorpyrifos)  when  numbers  reach  a  level   that  is  known  to  result  in  lower  yields.  Fir  instance,  in  Japan,  plants  are  sprayed  if  5%  of   stems  are  damaged  by  75  days,  because  it  is  known  that  this  is  affect  yields.   o Alternatively,  spray  routinely  with  bifenthrin,  fipronil,  or  chlorpyrifos  every  3-­‐4  weeks.  

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Avocado dieback    

Extension Fact  Sheet  

120

Common names:  Avocado  dieback,  Avocado  root  rot,  Phytophthora  root  rot,  Phytophthora   dieback,  Root  rot,  and  Jarrah  dieback  where  Eucalyptus  marginata  is  involved   Scientific  name:  Phytophthora  cinnamomi1.   Hosts:  Avocado  and  many  other  fruit  and  nut  trees  (macadamia),  fruits  (pineapple),  ornamentals   (roses,  azaleas),  plus  wild  species  in  the  USA  (American  chestnut,  Shortleaf  pine,  Fraser  fir),  in   Australia  (Banksia,  Darwinia,  Grevillea,  and  jarrah,  Eucalyptus  marginata),  and  Europe  (native   chestnut  and  cork  oak).  More  than  800  species  are  susceptible.   Distribution:  Worldwide.  It  is  recorded  from  Fiji  and  Samoa.    

Damage   Avocado  dieback  affects  the  small  feeder  roots  of  the  tree.  The  pathogen  causes  a  gradual   decline  of  older  trees  or  a  quick  death  of  those  that  are  younger.  The  leaves  become  smaller   than  normal,  green-­‐yellow  and  brown  at  the  tips;  they  may  wilt  during  the  heat  of  the  day.  Bare   twigs  and  small  branches  appear  as  they  fail  to  produce  leaves,  a  symptom  known  as  dieback   (photos).  Fruit  are  small  and  progressively  fewer  as  the  disease  advances.  Dieback  continues   with  ever  more  wilting  and  loss  of  leaves  until  the  tree  dies.  In  addition  to  the  damage  of  the   small  roots,  cankers  may  occur  on  the  stem  at  or  below  soil  level.    

Biology and  Life  Cycle   Phytophthora  is  not  a  fungus  although  everything  about  its  biology  and  life  cycle  is  fungus-­‐like.  It   belongs  to  the  water  moulds  or  oomycetes.  It  has  motile  spores,  called  zoospores,  produced  in   flask-­‐shaped  organs  -­‐  sporangia  (diagram  below2).  The  zoospores  swim  in  the  soil  water  and  in   this  way  find  and  infect  the  roots,  until  the  whole  root  system  is  destroyed  and  the  plant  dies.   During  unfavourable  conditions  for  P.  cinnamomi,  i.e.  when  there  are  no  hosts  to  infect  or  soil   conditions  are  too  dry  for  spread,  two  types  of  thick-­‐walled  resting  pores  form:  i)   chlamydospores  (common),  and  ii)  oospores  produced  only  when  different  strains  mate.  Both   can  survive  for  several  years.   1 Much if the information is from Gerlach WWP (1988) Diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany 2 Rudman T (2005) Interim Phytophthora cinnamomi management guidelines. Nature Conservation Report 05/7, biodiversity Conservation Branch, Department of Primary Industries, Water and Environment, Hobart.

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  the  foliage  that  gradually  becomes  more  yellow  and  wilts  during  the  hottest  part  of  the   day;  look  for  the  appearance  of  twig  dieback.  Dig  up  some  of  the  roots,  remove  the  soil  by   washing,  and  look  for  the  darkening  (or  death)  of  the  feeder  roots  –  the  very  youngest  roots.    

Management QUARANTINE   Most  countries  legislate  to  prevent  the   movement  of  untreated  plants  across  their   borders;  however,  it  is  also  important  to  restrict   movement  of  plants,  plant  parts  and  soil  within   countries.  Plants  from  nurseries  are  a  particular   risk,  so  do  the  following:   • • • • •

Soil mixes  should  be  steam-­‐air  pasteurised   (30  mins  at  60°C).   Water  sources  should  be  free  from   contamination.   Pots  should  be  free  from  soil  and  sterilised   before  use  by  soaking  in  disinfectant.   Plants  brought  into  the  nursery  should  be  as   cuttings  or  certified  free  from  disease.   Tools  use  in  propagation  practices  should  be  washed  free  of  soil,  as  should  foot  ware.  

CULTURAL CONTROL   Cultural  control  methods  offer  the  best  chance  of  reducing  Avocado  dieback.  It  is  important  to   remember  that  the  disease  spreads  by  movement  of  infected  planting  material,  contaminated   tools,  and  water  running  over  infested  areas,  so  do  the  following:    

• • •

• •

Avoid introduction:  Take  care  not  to  introduce  the  disease  into  a  new  planting  with   contaminated  plants,  soil,  tools,  footwear,  vehicles,  or  storm  water;  if  purchasing  from  a   nursery  make  sure  that  the  nursery  is  using  procedures  detailed  above  under  Quarantine.   Site  selection:  Make  sure  that  the  area  is  well  drained;  avoid  planting  where  waterlogging   occurs.  Dig  holes,  fill  with  water  and  check  that  the  water  drains  away  within  an  hour  or  so.     Organic  matter:  At  planting,  and  at  other  times,  regardless  whether  the  pathogen  is  present   or  not,  add  organic  matter,  such  as  mulches  (but  keep  away  from  the  base  of  the  trees),   manures  and  composted  materials.  Mulches  rich  in  cellulose  reduce  P.  cinnamomi.   Hygiene:  Disinfect  tools,  machinery,  especially  tyres,  and  boots  regularly.   Replanting:  If  plants  die,  remove  as  much  of  the  root  system  as  possible,  and  dispose  by   burning.  If  replanting  do  not  use  the  same  hole  but  plant  upslope  from  the  dead  one,  and   add  organic  matter  and  ensure  there  is  good  drainage.  A  light  liming  may  be  beneficial.  

CHEMICAL CONTROL   • • •

Apply fungicides  containing  potassium  phosphonate  as  a  spray  or  by  trunk  injection.     If  trees  are  injected,  and  there  are  no  symptoms,  do  it  once  a  year  when  leaf  flushes  have   greened  and  hardened,  or  twice  a  year  -­‐  November  and  March  -­‐  if  symptoms  are  present.     If  trees  are  sprayed,  apply  six  sprays,  4-­‐6  weeks  apart,  between  November  and  April.     Do  not  spray  phosphonate  on  dieback-­‐affected  trees,  because  the  trees  will  not  take  up   enough  of  the  chemical.    

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Banana Bunchy  Top    

Extension Fact  Sheet  

121

Common  names:  Banana  bunchy  top,  Bunchy  top  of  banana   Scientific  name:  Banana  bunchy  top  nanavirus   Hosts:  Banana  and  others  in  the  genus  Musa.   Distribution:  It  is  common  in  Asia,  Africa  and  Oceania,  and  present  in  USA  (Hawaii).  It  is   recorded  from  Fiji,  Samoa  and  Tonga.    

Damage   Banana  bunchy  top  (BBT)  is  a  virus  disease  of  bananas.  In  the  past,  the  disease  has  devastated   banana  industries  in  Australia,  Fiji,  Samoa  and  Tonga.  Today,  it  is  causing  much  damage  in   Pakistan  and  is  spreading  in  DR  Congo.  Plants  that  are  infected  when  young  rarely  produce  a   fruit  bunch.  When  diseased  suckers  are  planted  they  become  severely  stunted  and  they  do  not   produce  fruit.  Plants  infected  at  a  later  growth  stage  may  produce  a  distorted  bunch.  In  Pacific   island  countries,  the  failure  to  select  healthy  planting  material  has  resulted  in  plantations   showing  20%  of  the  plants  with  BBT  in  the  first  year,  and  major  losses  within  2-­‐3  years  

Biology and  Life  Cycle   Plants  have  narrow,  progressively  shorter  leaves  with  little  distance  between  them,  hence  the   name  “bunchy  top”.  Leaf  edges  often  roll  upwards  with  yellow  margins  (photo,  left1).  The  most   characteristic  symptoms  are  short,  dark-­‐green  dots  and  dashes  along  the  minor  leaf  veins,  so-­‐ called  “morse-­‐code”  patterns,  which  form  hooks  curving  downwards  near  the  edge  of  the  midrib   (photo,  right).  Hold  the  leaf  up  to  the  light  and  view  from  the  underside.         The  virus  is  spread  by  an  aphid,  Pentalonia  nigronervosa  (see  Fact  Sheet  no.  103).  It  takes  more   than  4  hours  of  feeding  on  a  diseased  plant  before  aphids  become  infected  with  the  virus.  But   once  infected,  the  aphids  continue  spreading  the  virus  until  they  die.  Aphids  live  for  15-­‐20  days.   The  virus  is  not  transmitted  on  tools  or  through  the  soil.     1

Photo of Banana bunchy top virus (Richard Markham, ACIAR).

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  plants  with  stunted,  short,  bunched  leaves,  with  the  “morse-­‐code”  patterns  (dot-­‐dash)   symptom.  Yellowing  of  the  leaf  margins  also  suggests  BBT,  though  this  can  be  caused  by  other   problems.  There  are  commercial  ELISA  kits  to  detect  the  disease.  Molecular  techniques  using   PCR  (polymerase  chain  reaction)  are  more  sensitive.    

Management QUARANTINE   Banana  plants  for  should  be  transferred  between  countries  as  tissue  cultures  and  tested  to   ensure  that  they  are  free  of  all  known  banana  viruses.  Plants  of  many  varieties  of  bananas,   tested  to  internationally  agreed  standards2,  can  be  obtained  from  the  INIBAP  transit  centre  in   Belgium,  and  from  IITA,  Nigeria.  

NATURAL ENEMIES   In  Tonga,  Aphidius  colemani,  a  parasitic  wasp,  was  released  for  biological  control  of  the  aphid,   but  results  were  disappointing.  

CULTURAL CONTROL   Key  actions  in  managing  BBT  are:  a)  the  monitoring  of  banana  plantations  for  BBT  symptoms;   and  b)  rapid  treatment  of  affected  plants.     BBT  disease  can  be  effectively  controlled  by  the  eradication  of  diseased  plants  and  the  use  of   virus-­‐tested  planting  material.  If  the  disease  is  found  in  the  field,  do  the  following:   • Before  destruction,  spray  diseased  plants  with  kerosene  or  insecticide  to  kill  all  aphids.     • Within  48  hours,  dig  out  the  stool,  including  the  main  plants  and  all  suckers.   • Chop  the  plants,  including  the  corms,  into  small  pieces.   • Alternatively,  treat  the  diseased  plant  with  herbicide  (e.g.  glyphosate,  100ml/L).   • If  using  herbicide,  inspect  the  treated  plants  regularly  to  make  sure  they  are  dead.    

RESISTANT varieties   All  varieties  of  banana  are  susceptible,  although  some  may  take  longer  to  develop  symptoms  or   may  escape  because  of  aphids  like  some  varieties  more  than  others.  

CHEMICAL CONTROL   The  choice  of  chemicals  for  killing  aphids  on  diseased  plants  before  they  are  removed  from  the   plantation  depends  on  whether  they  grown  for  household  use  or  for  sale.     • Banana  for  home  use:  Use  soap  solution,  or  better,  horticultural  soap  (See  Fact  Sheet  no.   56d).  Aim  to  spray  the  “throat”,  the  V-­‐shaped  area  where  the  leaves  meet  and  where  aphids   hide.     • Commercial  plantations:  The  following  have  been  recommended  for  the  Pacific  islands   region:  dimethoate  (400g/L),  used  at  75ml/100L;  diazinon  (200g/L),  used  at  1.5ml/L;   acephate  (75%  WP),  used  at  1.3g/L.  

2

http://www.bioversityinternational.org/fileadmin/bioversity/publications/pdfs/502_Musa_spp.__2nd_edition_.pdf? cache=1367968072 AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Malayan Leaf  Spot    

Extension Fact  Sheet  

122

Common  name:  Malayan  leaf  spot  of  banana   Scientific  name:  Haplobasidium  musae1.   Host:  Banana.   Distribution:  Highlands  of  peninsular  Malaysia  and  Papua  New  Guinea,  Fiji,  Samoa  and  Tonga.    

Damage   This  is  usually  a  minor  disease,  although  severe  development  occurs  in  areas  of  Fiji  where  there   is  more  and  1  m  annual  rainfall,  and  temperatures  are  below  24°C.  It  is  also  common  in  Samoa   in  the  cooler  area,  especially  if  the  bananas  are  shaded,  or  are  sprayed  with  oil  against  other   diseases.  

Biology and  Life  Cycle   Symptoms  vary  in  different  locations.  In  Fiji,  lesions  on  the  upper  leaf  surface  are  diamond   shape,  light  grey,  2-­‐4  x  3-­‐5.5  mm,  and  have  0.5  mm  wide  black  borders.  Dark  growth  of  the   fungus  occurs  on  the  under  surface  of  the  leaves.  Spores  are  produced  in  these  black  velvety   areas.  The  spots  are  scattered  over  the  entire  leaf;  they  do  not  merge,  but,  if  numerous,  parts  of   the  leaf  turn  yellow.  Symptoms  in  Samoa  are  similar1.     In  Papua  New  Guinea  and  Malaysia,  lesions  have  dark  purple  borders,  are  pale  grey  on  the   upper  and  pale  brown  on  the  lower  surface,  and  are  either  oval  or  round.  Large  patches  of  dead   tissue  occur  when  the  spots  merge.       Spores  from  the  lower  leaf  surface  are  spread  in  wind  and  rain,  and  mainly  infect  the  older   leaves.     1 Photo is from Gerlach WWP (1988) Plant diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany.

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  the  diamond  shaped  spots  with  black  borders  on  the  upper  surface  of  the  leaf,  with   black  velvety  spores  masses  below.  Note  that  they  are  much  smaller  than  Diamond  leaf  spot,   which  are  up  to  10  cm  long  (see  Fact  Sheet  no.  72).  

Management Malayan  leaf  spot  is  only  a  minor  disease,  and  even  at  places  of  high  elevation,  where  it  is  cool   and  rainfall  is  high,  damage  is  unlikely  to  result  in  the  need  for  control  measures.     CULTURAL  CONTROL   Infection  from  this  disease  is  greater  if  the  bananas  are  shaded;  therefore,  remove  shade  or   plant  bananas  in  the  open.     RESISTANT  VARIEITES   No  information.   CHEMICAL  CONTROL   The  disease  is  control  by  the  fungicides  that  are  used  for  Black  Sigatoka  (see  Fact  Sheet  no.  02),   namely:     Protectant  fungicides:   • dithiocarbamates  (e.g.,  mancozeb)   • Banana  misting  oil.   Systemic  fungicides:   • triazoles  (e.g,  propiconazole  and  flusilazole)   • strobilurins  (e.g.,  azoxystrobin).       It  is  important  to  rotate  the  fungicides  in  the  different  groups  to  prevent  the  build  up  of   resistant  strains  of  the  fungus.  In  drier  times,  mancozeb  can  be  used  alone.          

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Banana Rust  

Extension Fact  Sheet  

123

Common  name:  Banana  leaf  rust   Scientific  name:  Uredo  musae.   Host:  Banana.   Distribution:  Pacific,  including  the  Philippines.  Present  in  Fiji,  Samoa,  Tonga  and  Solomon   Islands.    

Damage   A  fungus  causes  the  disease,  but  is  it  rarely  important.  Reports  from  Samoa  (1981)  and   Philippines  (1971)  suggest  it  was  serious  when  only  benzimidazole  fungicides,  e.g.  benomyl,   were  used  against  Black  Sigatoka  disease.  However,  benomyl  is  no  longer  used,  and  in  many   countries  its  registration  has  been  cancelled.  For  instance,  in  Australia,  it  became  illegal  to   supply  or  use  products  containing  benomyl  after  6  December  20061.  

Biology and  Life  Cycle   Dark  brown  to  black  streaks  appear  on  the  top  of  the  leaves,  often  surrounded  by  yellow  halos   (photo,  left2).  The  streaks  are  more  numerous  on  the  lower  surface  of  the  leaves  (photo,  right3).   They  are  slightly  raised,  and  feel  rough  to  the  touch  on  the  underside  of  the  leaf  due  to  the   spore  masses  of  the  fungus.  If  the  disease  is  severe,  the  leaves  may  turn  yellow.  Mainly  the  older   leaves  are  affected.  

  1

http://www.apvma.gov.au/products/review/completed/benomyl.php. Photo from Diseases of fruit crops in Australia (2009). Editors, Tony Cooke, Denis Persley, Susan House. CSIRO Publishing. 3 Photo from Gerlach WWP (1988) Plant Diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany. 2

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Detection and  Inspection   Look  for  the  slightly  raised  “rough”  spores  masses  associated  with  blackish-­‐brown  streaks,   especially  on  the  underside  of  the  leaves.  

Management This  is  only  a  minor  disease,  and  control  measures  are  not  necessary.     CHEMICAL  CONTROL   In  commercial  plantings,  the  rust  is  controlled  by  the  fungicides  that  are  used  for  Black  Sigatoka   (see  Fact  Sheet  no.  02).  There  is  evidence  that  the  disease  was  worse  when  benomyl  was  used   extensively,  and  also  when  oil  is  used  on  its  own.      

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Banana Freckle  

Extension Fact  Sheet  

124

Common  name:  Banana  freckle   Scientific  name:  Previously,  Phyllosticta  musarum  and  its  sexual  form  Guignardia  musae;  now   four  species  are  recognised:  P.  cavendishii,  P.  musarum,  P.  maculata  and  Guignardia  stevensii.   Host:  Banana.  Note,  P.  cavendishii  is  the  only  species  infecting  Cavendish  AAA1  bananas   (although,  like  the  other  Phyllosticta  species  it  also  infects  those  in  the  AAB  and  ABB  groups).   Distribution:  Asia,  USA  (Hawaii),  Oceania.  Present  in  Fiji,  Samoa  (P.  maculata  is  in  American   Samoa),  Tonga  (P.  cavendishii)  and  Solomon  Islands.  G.  stevensii  is  found  only  in  Hawaii.    

Damage   Freckle  is  a  fungal  disease  that  affects  the  fruit  as  well  as  the  leaves.  It  can  be  a  serious  disease   as  the  fungus  infects  at  any  stage  of  growth,  and  becomes  more  serious  over  time.  On  the  fruit,   the  fungus  only  invades  as  far  as  the  skin,  but  the  damage  that  it  causes  makes  the  fruit   unsightly  and  affects  its  market  acceptability.     In  Taiwan  and  Sri  Lanka,  where  the  Cavendish-­‐infecting  strain  occurs,  freckle  is  more  important   than  Black  Sigatoka  (see  Fact  Sheet  no.  02);  here,  it  causes  premature  death  of  the  leaves,  and   reduces  yield  significantly.  In  the  Philippines,  it  is  second  to  Black  Sigatoka  in  importance.  

Biology  and  Life  Cycle   Individual  reddish-­‐brown  spots  occur,  0.5-­‐1  mm  diameter,  later  turning  dark  brown  to  black,   usually  on  the  upper  surface  of  leaves  (photo,  left2).  They  occasionally  form  dense  groups.  The   spots  contain  sac-­‐like  structures,  which  contain  spores  of  the  fungus.  They  protrude  from  the   leaf  surface  and  feel  rough  to  the  touch,  like  sandpaper.  If  there  are  large  numbers  of  spots,  the   leaves  turn  yellow  and  die  early  (photo,  right).  Black  spots  develop  on  green  fruit  and  fruit  stalks.   They  may  completely  cover  the  fruit  by  the  time  of  harvest  (photo,  below).   1

A way of classifying bananas on i) number of chromosomes and ii) ratio of the parents Musa accuminata and M. balbisiana. 2 Photos from Diseases of fruit crops in Australia (2009). Editors, Tony Cooke, Denis Persley, Susan House. CSIRO Publishing. AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   Spores  of  the  fungus  are  spread  in  wind  and  rain.  The  fungus  is  spread  over  large  distances  with   the  movement  of  infected  fruit,  leaves   and  suckers  used  for  planting.  It  is   thought  that  the  fungus  survives  in   diseased  leaves,  although  it  is  not  known   for  how  long.  

Detection and  Inspection   Look  for  slightly  raised  “rough”  spores   masses  associated  with  blackish-­‐brown   streaks,  especially  on  the  underside  of  the   leaves.  Look  for  smaller  rough  spots  on   the  fruit.  

Management QUARANTINE   The  four  species  recently  identified  by  morphological  and  molecular  means  have  very  different   distributions,  so  there  is  need  for  care  to  prevent  further  spread  of  these  fungi.  G.  stevensii   occurs  only  in  Hawaii.  Both  P.  maculata  and  P.  cavendishii  occur  in  the  South  Pacific,  but  with   uncertain  distributions,  except  they  are  present  in  American  Samoa  and  Tonga,  respectively.  It   should  also  be  noted  that  the  Cavendish  species  has  recently  been  recorded  in  the  Northern   Territory  of  Australia,  whereas  previously  only  P.  maculata  was  known  there  and  in  Queensland.    

CULTURAL CONTROL   Control  would  only  be  worthwhile  if  P.  cavendishii  were  present  and  Cavendish  AAA  bananas   were  grown  (as  in  Taiwan),  or  in  the  unlikely  event  that  cooking  bananas  (e.g.  ABB  and  ABB)   were  grown  commercially;  in  which  case  do  the  following:   • •

Bag bunches  as  soon  as  the  male  bud  has  been  removed  to  help  prevent  fruit  infection.   Cut  out  diseased  patches  on  leaves.  

RESISTANT VARIETIES   Cavendish  varieties  have  resistance  to  the  disease  caused  by  P.  maculata  and  P.  musarum.  

CHEMICAL CONTROL   The  same  applies  as  noted  under  cultural  control  for  Cavendish  and  plantain  varieties.  In  most   countries  in  the  Pacific,  spraying  would  only  be  considered  for  Cavendish  varieties  grown   commercially.  However,  in  this  case,  even  if  P.  cavendishii  were  present,  the  fungicides  used   against  Black  Sigatoka  would  most  likely  control  it  (see  Fact  Sheet  no.  02).  In  commercial   plantations,  the  main  types  of  fungicides  used  are:   Protectant  fungicides:   • dithiocarbamates  (e.g.,  mancozeb);   • Banana  misting  oil.   Systemic  fungicides     • triazoles  (e.g,  propiconazole  and  flusilazole);     • strobilurins  (e.g.,  azoxystrobin).       It  is  important  to  rotate  the  fungicides  in  the  different  groups  to  prevent  the  build  up  of   resistant  strains  of  the  fungus.  In  drier  times,  mancozeb  can  be  used  alone.     AUTHOR  •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Banana Black  End  Rot    

Extension Fact  Sheet  

125

Common  names:  Banana  anthracnose,  Tip  rot  of  banana,  Crown  rot,  Black  end  rot   Scientific  name:  Colletotrichum  musae1.   Host:  Banana.   Distribution:  Worldwide.  It  is  present  in  Fiji,  Samoa,  Solomon  Islands  and  Tonga.    

Damage   A  fungus  causes  anthracnose2  and  black  end  rot  of  banana.  The  disease  is  a  post-­‐harvest   problem  affecting  the  finger  of  the  fruit.  Symptoms  do  not  occur  on  the  leaves.  The  disease  can   be  serious  on  overripe  fruit,  or  on  unripe  fruit  that  is  damaged  by  being  badly  handled  and   bruised  after  harvest.  

Biology and  Life  Cycle   On  the  fruit:  circular  to  oval,  brown  or  black,  sunken  spots  occur,  and  as  they  age  pink  spore   masses  occur  in  the  centre  of  the  spots.  The  spots  may  join  together  covering  large  areas  of  the   fingers.     On  the  stem  ends  of  the  fruit:  blackening  and  rotting  of  the  cut  or  otherwise  damaged  ends  of   the  fingers  where  they  were  previously  attached  to  the  crown  of  the  bunch.       The  fungus  readily  colonises  dead  and  dying  banana  leaves  and  fruits,  and  spores  are  formed  in   large  numbers;  the  spores  are  then  spread  in  wind-­‐driven  rain  or  perhaps  by  insects  onto   1

Much of the information is from Diseases of fruit crops in Australia (2009). Editors, Tony Cooke, Denis Persley, Susan House. CSIRO Publishing. 2 Anthracnose is the name given to diseases caused by Colletotrichum (and some other) fungi. AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

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P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A   bunches  of  green  fruit.  Here,  infection  takes  place,  but  the  fungus  does  not  cause  spots  at  this   time;  it  is  said  to  be  “latent”,  meaning  that  it  is  dormant  waiting  for  the  right  conditions  for   further  development.  Infection  occurs  20-­‐40  days  after  bunch  emergence.  Later,  when  the   bunch  starts  to  ripen,  the  fungus  starts  to  grow  once  more  and  rots  appear  on  the  fruit.       Note,  these  symptoms  should  not  be  confused  with  ageing  spots  that  develop  on  ripe  fruit.  

Detection and  Inspection   Look  for  large,  black,  round,  sunken  spots  on  the  fruit.  Look  for  the  pink  spore  masses  of  the   fungus  in  the  centres  of  the  spots.  Look  for  rots  on  the  broken  or  cut  ends  of  single  bananas.  

Management CULTURAL  CONTROL   • • • • •

Bag bunches  as  soon  as  possible  after  the  male  bud  has  been  removed  to  help  prevent  fruit   infection;  bags  are  usually  applied  when  the  fingers  are  horizontal.   Reduce  the  number  of  fungal  spores  by  removing  old  hanging  leaves  and  the  remains  of   flowers  from  the  plantation.   Handle  banana  bunches  carefully  after  harvest  to  avoid  bruising  and  wounding,  both  in  the   field  and  in  the  packing  station.   Keep  packing  sheds  clean.  Remove  the  remains  of  leaves,  flowers  and  rejected  fruits  from   the  packing  shed.   Trim  the  crown  –  the  part  attached  to  the  bunch  stem  –  with  a  knife  so  that  the  cut  surface   is  smooth.    

RESISTANT VARIETIES   No  information.   CHEMICAL  CONTROL   In  commercial  production,  hands  of  bananas  are  treated  with  fungicides  after  harvest.   Previously,  benomyl  was  used,  but  since  the  cancelation  of  its  registration  in  many  countries,   other  benzimidazole  fungicides  (e.g.  thiobendazole)  or  sterol  biosynthesis  inhibitors  are  used  in   packing  stations  before  the  hands  are  put  into  boxes.          

AUTHOR •  Grahame  Jackson   EDITORS  •  Sione  Foliaki,  Amena  Banuve,  Mereia   Lomavatu,  Aleni    Uelese,  Parate  Matalavea  

Produced with  support  from  Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production. Funded  by  ACIAR,   Canberra  in  collaboration  with  SPC  

READ THE  INSTRUCTIONS  BEFORE  USING  ANY  PESTICIDE


P L A N T P R O T E C T I O N   |   F I J I ,   S A M O A ,   S O L O M O N   I S L A N D S ,   T O N G A  

Rhizoctonia Web  Blight  

Extension Fact  Sheet  

126

Common  names: