Tulip diseases

shown for each growth stage ‘Solving a problem starts with recognising it’ Tulip diseases aims to help everyone who works with tulips to identify abnormalities quickly and easily.

Clear images and concise texts provide quick insight into damage profiles, causes, and control methods, covering more than 40 diseases, infestations, and other abnormalities. And you can only combat a disease or disorder if you know the cause.

Tulip diseases will help you do that.

www.roodbont.com

Tulip diseases shown for each growth stage Cor Conijn

Tulip diseases

Tulip diseases shown for each growth stage

www.flowerfullconsultancy.nl

ISBN 978-90-8740-311-9

9 789087 403119

Cor Conijn

Contents Search by disease 6 Search by cause of the disease 7 Introduction 8 1 Bulb 10 Sour (Fusarium oxysporum) 12 Dry bulb mite (Aceria tulipae) 14 Mechanical damage 16 Blue mould, penicillium bulb rot (Penicillium spp.) 18 Rhizoctonia disease (Rhizoctonia solani) 20 Botrytis (Botrytis tulipae) 22 Potato rot nematode (Ditylenchus destructor) 24 Yellow spot (Curtobacterium) 26 Pseudo cork spot 28 Gummosis 30 Bulb blueing 32 Nose rot 34 Rattle bulb 36 Black mould (Aspergillus niger) 38 Tulip bulb aphid (Dysaphis tulipae) 40 Stem nematode (Ditylenchus dipsaci) 42 2 Growth 44 Tulip fire, ‘stekers’ or ‘primaries’ (Botrytis tulipae) 48 Tulip fire, spots (Botrytis tulipae) 50 Rhizoctonia disease (Rhizoctonia solani) 52 Tulip breaking virus (TBV) 54 Augusta disease (OMMV, TNV) 56 Tulip virus X (TVX) 58 Hell fire (Curtobacterium) 60 Frost damage 62 Dry bulb mite (Aceria tulipae) 64 Tulip grey bulb rot (Rhizoctonia tuliparum) 66 Grey mould (Botrytis cinerea) 68 Short brown roots 70 Soapers 72 Sweating 74 Leaf chlorosis 76 Water damage 78 Mouse damage 80 Soft rot 82 Stem nematode (Ditylenchus dipsaci) 84 4

Tulip disea ses

3 Flowering 86 Tulip breaking virus (TBV) 90 Tulip virus X (TVX) 92 Augusta disease (OMMV, TNV) 94 Rattle virus (TRV) 96 Tulip fire, leaf and flower spots (Botrytis tulipae) 98 Tulip fire, leaf and stem fire (Botrytis tulipae) 100 Grey mould (Botrytis cinerea) 102 Leaf tip wilting (Trichoderma viride) 104 Dry bulb mite (Aceria tulipae) 106 Bud necrosis (kernrot) 108 Flower desiccation, blindness 110 Flower desiccation, papery flowers 112 Pythium root rot (Pythium ultimum) 114 Toppling, watery stems 116 Leaf topple and flower blemish 118 Multiple stems or shoots 120 Cracking flowers 122 Hollow stems 124 Fusarium bulb rot (Fusarium oxysporum) 126 Pink rot (Phytophthora spp.) 128 Rat and mouse damage 130 Slug damage 132 Pratylenchus root rot (Pratylenchus penetrans) 134 Black slime disease (Sclerotinia bulborum) 136 Stem nematode (Ditylenchus dipsaci) 138 4 Disease overview 140 Fusarium bulb rot, ‘sour’ (Fusarium oxysporum) 142 Blue mould (Penicillium spp.)

143 Bud necrosis (kernrot) 144 Tulip fire (Botrytis tulipae) 145 Dry bulb mite (Aceria tulipae) 146 Yellow spot/hell fire (Curtobacterium) 147 Rhizoctonia disease (Rhizoctonia solani) 148 Stem nematode (Ditylenchus dipsaci) 149 Index 150

Cont e n t s

5

Search by disease Disease name Augusta disease Black mould Black slime disease Blue mould Blueing Botrytis Bud necrosis (kernrot) Cracking flowers Damages Dry bulb mite Flower desiccation Frost damage Fusarium bulb rot Gnawing damage Grey bulb rot Grey mould Gummosis Hell fire Hollow stems Leaf chlorosis Leaf tip wilting Multiple stems or shoots Nose rot Pink rot Potato rot nematode Pratylenchus root rot Pseudo cork spot Pythium root rot Rattle bulb Rhizoctonia disease Short brown roots Slug damage Soapers Soft rot Stem nematode Sweating Tobacco rattle virus Topple (leaf and stem) Tulip breaking virus Tulip bulb aphid Tulip fire Tulip virus X Water damage Yellow spot

6

Cause Page OMMV and TNV viruses 56, 94 Aspergillus niger 38 Sclerotinia bulborum 136 Penicillium spp.

18, 143 Excessive growth 32 Botrytis tulipae 22, 48, 50, 98, 100, 145 Ethylene + mites 108, 144 Boron deficiency 122 Falling and bashing 16 Aceria tulipae 14, 64, 106, 146 Blasting/papery flowers 110, 112 Freezing 62 Fusarium oxysporum 12, 126, 142 Rats and mice 80, 130 Rhizoctonia tuliparum 66 Botrytis cinerea 68, 102 Ethylene 30 Curtobacterium 60, 147 Excessive root pressure 124 Iron deficiency 76 Trichoderma viride 104 Ethylene 120 Excessive bulb growth 34 Phytophthora spp.

128 Ditylenchus destructor 24 Pratylenchus penetrans 134 Harvested too white 28 Pythium ultimum 114 Excessively sealed skin 36 Rhizoctonia solani 20, 52, 148 Oxidising phenols 70 Grey field slug and heath slug 132 Fermentation 72 Pythium ultimum 82 Ditylenchus dipsaci 42, 84, 138, 149 Excessive root pressure 74 TRV 96 Calcium deficiency 116, 118 TBV 54, 90 Dysaphis tulipae 40 Botrytis tulipae 48, 50, 98, 100, 145 TVX 58, 92 Drowning 78 Curtobacterium 26, 147

Tulip disea ses

Search by cause of the disease Cause Disease name Page Nematodes Potato rot nematode (Ditylenchus destructor) 24

Pratylenchus root rot (Pratylenchus penetrans) 134

Stem nematode (Ditylenchus dipsaci) 42, 84, 138, 149 Bacteria Yellow spot/hell fire (Curtobacterium) 26, 60, 147 Animals Mouse gnawing 80, 130

Rat gnawing 130

Slug damage 132 Physiological Bulb blueing 32

Cracking flowers 122 Damage 16

Flower desiccation 110, 112

Frost damage 62 Gummosis 30

Hollow stems 124

Leaf chlorosis 76

Multiple stems or shoots 120

Nose rot 34

Pseudo cork spot 28

Rattle bulb 36

Short brown roots 70 Soapers 72 Sweating 74

Topple (leaf and stem) 116, 118

Water damage 78 Insects and mites Bud necrosis (Rhizoglyphus, Tyrophagus) 108, 144

Dry bulb mite (Aceria tulipae) 14, 64, 106, 146

Tulip bulb aphid (Dysaphis tulipae) 40 Fungi Black mould (Aspergillus niger) 38

Black slime disease (Sclerotinia bulborum) 136

Blue mould (Penicillium spp.)

18, 143

Fusarium bulb rot (Fusarium oxysporum) 12, 126, 142

Grey bulb rot (Rhizoctonia tuliparum) 66

Grey mould (Botrytis cinerea) 68, 102

Leaf tip wilting (Trichoderma viride) 104

Pink rot (Phytophthora spp.)

128

Pythium root rot (Pythium ultimum) 114

Rhizoctonia disease (Rhizoctonia solani) 20, 52, 148

Soft rot (Pythium ultimum) 82

Tulip fire (Botrytis tulipae) 22, 48, 50, 98, 100, 145 Viruses Augusta disease (OMMV, TNV) 56, 94

Tobacco rattle virus (TRV) 96

Tulip breaking virus (TBV) 54, 90

Tulip virus X (TVX) 58, 92

7

Introduction

The most common tulip diseases

Tulip diseases describes the most commonly occurring tulip diseases. It is indispensable for bulb growers, tulip forcers and businesses involved in garden and park planting. The book is set out so that you can look up the symptom set and associated description easily and quickly. To that end, the chapters are set out to cover the growing, bulb, plant growth and flowering phases. Each chapter begins with the most commonly occurring disease.

Bulb

Bulb storage: from harvesting to planting

Plant growth Field/greenhouse Phase 1: planting until flower bud Flowering

8

Field/greenhouse Phase 2: flowering until harvesting/cutting

Tulip disea ses

If you see an abnormality among the tulips, compare the symptoms with the pictures and descriptions. And you will be able to conclude quickly which type of disease or disorder it is.

Each symptom set has associated information about the disease or disorder, the cause, and a short description of the symptoms (damage profile), abnormalities, which types of plants can be affected (host plants), and how to combat and prevent the problem.

Information on symptoms Cause

Name of the bacteria, fungus, virus, nematode, insect, or mite, other animals, or physiological disorders.

Damage profile

Characteristic visual abnormalities that indicate the disease or disorder in the plant.

Special characteristics

Further useful information about the occurrence of the disease and its cause.

Host plants

Other susceptible plants or those on which the pathogen can reproduce.

Prevention

Measures for preventing or combating the disease or disorder.

Disease overview There is a full overview at the end of the book. It covers diseases or disorders that are complex, or those that occur in multiple phases of cultivation, with different symptoms at each stage. This section provides information on adverse effects you might still expect, or that you could have missed during an earlier stage. The images are set out in chronological order, from bulb to plant.

Int rod u c t i o n

9

1 Bulb

Bulb This chapter presents damage profiles and descriptions of pests, diseases and disorders that commonly occur during bulb storage, from harvesting through to planting.

Different diseases and damage profiles occur at the beginning of storage than later on. Some diseases are already evident at the time of harvesting. These have often already started while the bulbs were growing in the field. A variety of diseases can develop during storage and become visible later.

The following are examples of diseases and infestations that become evident during the period from point of harvest until planting time.

Diseases and disorders visible at: Harvesting

Botrytis, rhizoctonia disease

A few days or weeks after harvest

Pseudo cork spot, blueing, nose rot, sour and mechanical damage

A few months after harvest

Dry bulb mite, potato rot and stem nematode, yellow spot, and gummosis

End of storage

Rattle bulb, black mould, blue mould, aphids

1 Bul b

11

Bulb Sour Cause Fungus, Fusarium oxysporum f.sp. tulipae.

Damage profile Rotting spots, soft and dark with white mould, occur in the basal plate of the bulb or its scales. Affected bulbs give off a sour smell. The entire bulb can rot and then dry out and petrify. The rotten bulbs shrink, but their brown tunic does not.

Special characteristics Affected bulbs produce ethylene and are a food source for bulb and straw mites. The combination can cause bud necrosis (kernrot). Damage on bulbs provides access for the fungus. The risk of infection is greatest if damage occurs when bulbs are damp. The infection becomes evident during the storage process and spreads further in damp conditions.

Host plants Tulip – one cultivar can be more susceptible than another.

Prevention • Harvest bulbs with light brown tunics early and keep damage to the minimum.

• Dry your bulbs quickly after harvesting – wind dry within 24 hours.

• Dry the bulbs after every process (cleaning, counting, sorting, selecting) to prevent infection in damp damaged spots.

• Remove any affected bulbs in August or before planting.

• Adjust your crop rotation to one in six years.

• Only use healthy stock and plant your bulbs when the soil temperature is under 10°C. • Dip your bulbs in a fungicide solution before planting, according to current advice.

• Carry out a disease test. Take a sample of 125 bulbs evenly spread over the batch, both before and after treatment, and assess the rate of infection after six weeks’ storage at 20–23°C.

12

Tulip disea ses

Bulb

Bulbs with a fusarium infection, the left one in section – the entire bulb has soft rot with a white mould.

Sour bulb with gummosis (left) and loose tunic (right).

1 Bul b

13

Bulb Dry bulb mite Cause Mite, dry bulb mite (Aceria tulipae).

Damage profile Matt red or creamy yellow discolouration on the white scales, ranging from a spot on the outer scale to full discolouration on all of the scales. The first discoloured spots occur under the brown tunic, on the bulb’s tip or basal plate. Heavily infected bulbs lose weight, shrink, and become flaccid. The red discolouration looks similar to the same effect caused by sunlight, but that discolouration does not occur below the brown tunic.

Special characteristics Dry bulb mite is an infestation that occurs during dry and warm storage.

Bulbs from contaminated batches appear unaffected at harvest time: the first signs of damage on the scales only become visible after a few months of warm storage at a temperature above 20°C. Aceria tulipae can transmit the TVX virus (tulip virus X) from sick to healthy bulbs. These mites are very small, 0.25 x 0.07 mm, and impossible to see without magnification.

Host plants Tulip, alliums such as onions, garlic, and decorative alliums.

Prevention • Use healthy planting stock, bulbs that are free of dry bulb mite.

• Keep bulbs cool at < 20°C, or in a vented bulb store, and plant early to avoid heavy infestations.

• After harvesting, give the bulbs a CATT treatment, two sessions of 24 hours’ ULO (Ultra Low Oxygen).

• Clean your crates and storage space by removing old bulbs and disinfecting with hot water or steam.

• Do not store any (contaminated) garlic, onions, or decorative alliums in your tulip bulb store.

• Perform a check for dry bulb mite, to ensure that the batch is not contaminated. Take a representative sample of 125 bulbs from the batch, either at harvest or on delivery. Keep the samples in a box or sack, with all seams closed with tape, at a temperature of 23–25°C and assess whether there is any contamination after eight weeks.

• Spray the crop after flowering, using a systemic mite control product, according to current advice.

• Treat the bulbs immediately after harvesting with a mite eradication product, following currently valid advice.

14

Tulip disea ses

Bulb

A noticeable red discolouration of the white scale, caused by dry bulb mite â&#x20AC;&#x201C; the brown tunic has been removed from the bulb.

This bulb has cream and red discolouration caused by the dry bulb mite. In the section, you can even see red scale discolouration on the inner scales, and that the mite has penetrated deep into the bulb.

1 Bul b

15

2 Growth

Growth This chapter describes the diseases and infestations that can occur after planting up to the flower bud stage. Plants are affected after planting, just around the time of coming up or later.

There are diseases that only occur in bulb growing and not during forcing and vice versa, so we must distinguish between the different cultivation forms: bulb growing, producing flowers (open ground, pots, crates or forcing in water) and garden planting.

In addition, there are diseases and disorders that come in on the planted bulbs. These diseases or disorders have arisen in bulbs during growing, or later, during storage.

The table on the next page sets out the diseases and disorders, categorised into the cultivation type they occur in – i.e. in bulb growing, forcing or garden planting. If the disorder develops or occurs during the growing period from planting to flower bud in the field or greenhouse, it is marked with an ‘x’. If the diseases come with the bulb you plant, it is marked with a ‘b’. If there is an ‘x’ and ‘b’, the disorder can both occur during growth as well as come with the bulb.

2 Grow t h

45

Growth Tulip fire, ‘stekers’ or ‘primaries’ Cause Fungus, Botrytis tulipae.

Damage profile The shoot has stunted growth. The outer leaf is affected and that makes it grow crookedly. There is a watery, greyish-brown spot on the outer side of the first leaf, which turns into light brown necrotic tissue. A fungal growth of grey-brown spores occurs on the affected tissue. These plants are called ‘stekers’ (stickers) or ‘primaries’ in the Netherlands, because they keep on attempting to grow and are an infection source for others.

Special characteristics The fungal spores from ‘stekers’ can lead to tulip fire and spots in healthy plants.

‘Stekers’ come out of ground where tulips are grown annually, or when you plant infected bulbs (see botrytis in bulbs).

In damp conditions, the mould can grow right through the first leaf and then infect the ones underneath.

Host plants Tulips, occasionally lilies.

Prevention • Bulb cultivation • Disease detection – take care to remove any affected plants, starting from when they come up.

• Apply fungicide crop sprays according to current advice and guidelines, using decision support systems (a calculation of infection probability using the weather forecast and fungal pressure).

• Stick to a crop rotation programme of at least one year in three, and ensure all bulbs are removed from the field.

• Plough the land at the end of cultivation (no spading machines).

• Flood infected ground for six to eight weeks in summer.

• Select out infected bulbs and disinfect them according to current advice.

• Park and garden planting • Remove affected plants carefully.

48

Tulip disea ses

Growth

‘Stekers’ (stickers) or ‘primaries’ – the outer leaf grows crookedly through a botrytis infection.

A ‘steker’ in the field that has infected neighbouring plants with spores.

2 Grow t h

49

3 Flowering

Flowering This chapter describes diseases that are especially visible or occur in the period when tulips bloom, after flowering or around harvesting time.

Bulb and bulb flower production has become so developed through the years that there are diseases which only occur in bulb production and not during forcing and vice versa. We can make a clear distinction between the various types of cultivation, i.e. production of bulbs, or flowers (in open ground, pots/crates or water forcing), and garden plants.

In addition, there are diseases and disorders that come with the bulbs you plant. These diseases or disorders have started to affect the bulbs during growing, or later during storage.

The table on the next page sets out the diseases and disorders, categorised by where they occur – i.e. in bulb growing, tulip forcing or garden planting. If the disorder develops or occurs during the growing period from flowering until harvesting/ cutting, it is marked with an ‘x’. If the disease comes with the bulb you plant, it is marked with a ‘b’. If there is an ‘x’ and ‘b’, the disorder can both occur during growth and/or come with the bulb.

3 Flowe r i n g

87

Flowering Diseases from flowering until harvesting/ cutting

Bulb cultivation

Parks & gardens

Forcing (greenhouse) open soil

Forcing (greenhouse) pot/crate

Forcing (greenhouse) water

Tulip breaking virus

xb

b

b

b

b

Tulip virus X

xb

b

b

b

b

Augusta disease

xb

xb

xb

xb

b

Rattle virus (TRV)

xb

b

b

b

b

Tulip fire

x

x

x

x

Grey mould

x

x

x

x

Leaf tip wilting

x

x

Dry bulb mite

xb

xb

xb

xb

xb

Bud necrosis

b

b

b

b

b

Flower desiccation, blindness

b

b

b

b

b

x

x

x

x

x

x

x

x

x

Flower desiccation, papery flowers Pythium root rot

x

Topple Multiple stems or shoots

b

b

b

b

b

Cracking flowers

xb

xb

xb

xb

xb

Hollow stems

x

Fusarium bulb rot

x

Pink rot

x

x

x

Rat and mouse damage

x

x

x

x

x

Slug damage

x

x

Pratylenchus root rot

x

b

b

b

Black slime Stem nematode 88

x

x xb

xb

Tulip disea ses

Flowering Inundation for disease control Flooding land for a period (inundation) controls a variety of diseases in the soil. And many weeds and remaining bulbs and tubers cannot survive it. This method of soil disinfection, developed for and by the bulb production industry, is currently used extensively in the sandy soil of the Dutch dunes. Bulb producers include it in their crop rotation programmes, so that they can apply it in the summer period, between two crops.

They create a dyke made of soil around the levelled bulb-growing land, or use corrugated sheets as a surrounding dam. Then they seal off the drainage and pump water onto the land from nearby ditches. The water must be above ground level and stay there for six to eight weeks.

The soil life that is active in the soil then suffers oxygen deprivation quite quickly. Oxygen cannot penetrate through the water, and funguses, nematodes, and various types of weeds die off. That makes this a good control method for diseases such as tulip fire, tulip grey bulb rot and nematodes (stem, lesion and potato tuber).

Tulip field inundation in Julianadorp (the Netherlands).

3 Flowe r i n g

89

4 Disease overview

Disease overview This chapter covers the diseases with their damage profiles during each stage of growth. All the damage profiles, from bulb to flower, are shown here together. This makes it easy to see the damage profiles you can expect at any stage, and which ones you may have missed during an earlier phase.

Disease

Bulb

Plant growth

Flowering

Fusarium bulb rot

‘Sour’, soft rot, calcification

Plants coming up poorly

Blue plants

Blue mould

Tunic, bulblet, scales, bulb tip

Root crown, bulb

Bud necrosis (kernrot)

Ethylene + bulbmite, space in bulb and open shoot

Normal

Flower necrosis

Tulip fire

‘Scabby’ spots

Primary infectors

Spots, leaf, flower, and stem fire

Dry bulb mite

Red and cream discolouration

Plants coming up poorly

Flower bud malformation and stains

Yellow spot/ hell fire

Yellow spot

‘Primaries’, hell fire

Hell fire

Rhizoctonia disease

Tunic and scale damage

Plants coming up poorly

Affected leaves and stems

Stem nematode

Discolouration, and rotting

Plants coming up poorly

Affected leaves, flowers, and stems

4 Dis e a s e ove r v i ew

141

Disease overview Fusarium bulb rot, ‘sour’ (Fusarium oxysporum)

Starting bulb infestation.

White fungus on the affected bulb.

Sour bulbs with gummosis (left) and loose tunic (right).

The ‘sour’ bulb at the centre does not come up (water forcing).

A stunted and yellowing plant through a fusarium infection.

A plant dying off purple, through fusarium.

142

Tulip disea ses

Disease overview Blue mould (Penicillium spp.)

Mould on the tunic.

A bulblet suffering an infection after being bashed.

Affected outer scale, localised damage visible.

In section, you see that only the outer scale is affected.

Bulb tip affected through the shoot growing out.

A bulb affected after planting through the roots and the basal plate.

Abundant fungal growth on a naked bulb at the time of bringing them into the greenhouse (water forcing).

143

4 Dis e a s e ove r v i ew

shown for each growth stage â&#x20AC;&#x2DC;Solving a problem starts with recognising itâ&#x20AC;&#x2122; Tulip diseases aims to help everyone who works with tulips to identify abnormalities quickly and easily.

Clear images and concise texts provide quick insight into damage profiles, causes, and control methods, covering more than 40 diseases, infestations, and other abnormalities. And you can only combat a disease or disorder if you know the cause.

Tulip diseases will help you do that.

www.roodbont.com

Tulip diseases shown for each growth stage Cor Conijn

Tulip diseases

Tulip diseases shown for each growth stage

www.flowerfullconsultancy.nl

ISBN 978-90-8740-311-9

9 789087 403119

Cor Conijn