Chavarria.ReunionEmpresa.7mayo2013.ver.final

A Spray Program for the Control of Black Sigatoka

ChavarrĂ­a-Carvajal, J.A., R. Macchiavelli, and E. HernĂĄndez.

Introduction: n

Bananas (Musa acuminata, AAA) and plantains (Musa acuminata X M. balbisiana, AAB) are two of the most important tropical fruits.

n

During fiscal year 2009-10 the combined farm gate value of bananas and plantains reached $78.7 million. Plantains rank first in economic importance with a farm gate value of $69.1 million, representing 8.76 % of the local gross agricultural income; while bananas for the same period had a farm gate value of $9.6 million or 1.2 % of the local gross agricultural income.

§ Bananas and plantains have several natural enemies including bacteria, viruses, insects, nematodes, and fungi.

§

Among the fungi, two related Ascomycetes are most significant: Mycosphaerella fijiensis (anamorph Pseudocercospora fijiensis), cause of black Sigatoka (BS), and M. musicola (anamorph Pseudocercospora musae), cause of yellow Sigatoka (YS) (Carlier et al., 2000).

§ During summer of 2004, BS was found on several plantain and banana farms in Puerto Rico on the western side of the Island and later (2006) was confirmed (Irish et al., 2006).

n

Since then BS has replaced the common YS, contributing to severe yield reductions on banana and plantain production.

n

BS is more aggressive and destructive than YS. Without proper management practices BS can cause losses in banana of 50% or higher (Stover, 1983), and losses in plantain of more than 40% (Chavarría-Carvajal 1986).

n

To produce commercially acceptable banana fruit, it is necessary to use fungicides intensively. Although YS management may require as many as 15 spray applications per year, up to 45 are used to manage BS. Thus, BS management is 3 to 4 times more expensive than YS.

Objectives: 1. To develop an effective spray program for the control of BS based on local weather conditions and available chemicals.

2. To evaluate the effects of spray program on BS severity index and yield parameters.

Materials and Methods

Isabela n

n n n n

Experimental site: located northwest of Puerto Rico An elevation of 15.0 meters above sea level Average annual rainfall 1,630 mm Average temperature 24.0 ° C. Predominant soil series is a Coto (Very-fine, kaolinitic, Typic isohyperthermic Eutrustox soil "), with pH of 6.2

Corozal § Experimental site: located northern Puerto Rico § An elevation of 209.1 meters above sea level § Average annual rainfall 2,500 mm § Average temperature 24.8 ° C. § Predominant soil series is a Corozal clay (clayed, mixed isohyperthemic aquic tropudult), with pH of 5.0

Experimental Design: Split Plot 6 replicates and 2 treatments.

Banana (Musa acuminata, AAA cv. ‘Grand Naine�)

Experimental Plot: 4 Rows- 10 plants each Plants studied: 2 rows- 5 plants each Spaced: 2.4 m rows X 2.1 m plants Population Density: 1,983 plants/hectare

Fungicides 1. Tilt (propiconazole): systemic, single-site fungicide, DMIsterol biosynthesis inhibitor.

2. Abound (azoxystrobin): systemic, single site fungicide, strobilurin or QoI-respiration inhibitor.

Tilt & Abound were used only during the rainy season or in periods of high inoculum pressure. Not more than two consecutive blocks. Not more of six cycles per year, per crop cycle to avoid the development of resistant strains.

3. Bravo WS (chlorothalonil): wide-spectrum, non-systemic, oil-incompatible, inhibits development young pathogen lesions on leaf surface. Applied during periods with medium inoculum pressure or when rainy season was not severe.

4. Manzate (mancozeb): protectant fungicide. Applied in periods with low inoculum pressure or during dry season.

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Propiconazole (Tilt), azoxystrobin (Abound), and macozeb (Manzate) applied in a oil-water emulsion.

Chlorothalonil (Bravo WS) applied in water.

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Fungicide applications from ground level with a motorized backpack sprayer calibrated to deliver a total volume of 34 to 45 L/acre (85-112 L/ha).

Severity Index % (S.I)1 Logarithmic, categorical scale (7 disease categories) Visual estimate for each leaf Based on the International rating system for BS Leaves numbered from top to down-wards Grade 0

Grade 1 (< 1%)

Grade 2 (1-5 %)

Grade 3 (6-15%) Grade 4 (16-33%) Grade 5 ( 34-50%) Grade 6 (> 51%)

1 Gauhlâ&#x20AC;&#x2122;s

modification of Stoverâ&#x20AC;&#x2122;s severity scoring system.

Severity Index % (S.I) Where:

ÎŁnb x 100 (N-1) T

n = number of leaves in each grade b = grade (0 = symptomless, 1 = less than 1% of leaf area affected (only streaks and/ or up to 10 spots), 2 = 1-5% of leaf area affected, 3 = 6-15% of leaf area affected, 4 = 16-33% of leaf area affected, 5 = 34-50% of leaf area affected, and 6 = 51-100% of leaf area affected.

N = total number of grades in the scale (7) T = total number of leaves assessed.

Craenen (1998)

RESULTS

Banana Plant Crop

Table 1. Spray Program for the control of BS on the banana plant crop at Isabela1

Fungicide

Date

Bravo WS

July 7, 2010

Cocktail Manzate

August 10, 2010

Bravo WS

August 25, 2010

Cocktail Tilt

September 8, 2010

Cocktail Tilt

September 29, 2010

Cocktail Abound

October 13, 2010

Cocktail Abound

October 21, 2010

Bravo WS

November 17, 2010

Bravo WS

December 15, 2010

Cocktail Tilt

January 4, 2011

1 Fungicides

Total: 10 spray cycles Cocktail Tilt (propiconazole): Cocktail Abound (azoxystrobin): Cocktail Manzate (mancozeb): Bravo WS (chlorothalonil):

3 2 1 4 10

(Tilt, Abound and Manzate) were sprayed in an oil-water emulsion, meanwhile Bravo WS in a water-emulsion, based on manufacturer recommendations. Orchard Oil BVA#15 based on manufacturer recommendations.

Table 2. Spray Program for the control of BS on the banana plant crop at Corozal1

Fungicide

Date

Cocktail Tilt

June 18, 2010

Cocktail Tilt

July 07, 2010

Cocktail Abound

July 22, 2010

Cocktail Abound

August 06, 2010

Bravo WS

August 23, 2010

Cocktail Tilt

September 10, 2010

Cocktail Tilt

September 24, 2010

Cocktail Abound

October 07, 2010

Cocktail Abound

October 22, 2010

Bravo WS

November 05, 2010

Bravo WS

November 26, 2010

1 Fungicides

Total: 11 spray cycles Cocktail Tilt (propiconazole): 4 Cocktail Abound (azoxystrobin): 4 Bravo WS (chlorothalonil): 3 11

(Tilt, Abound and Manzate) were sprayed in an oil-water emulsion, meanwhile Bravo WS in a water-emulsion, based on manufacturer recommendations. Orchard Oil BVA#15 based on manufacturer recommendations.

Table 3. BS severity index on banana plant crops at Isabela and Corozal Isabela: Chemical

SI (%)

SI (%)

Flowering

Harvesting

None

47.88 A

100.00 A

Yes

35.90 B

83.72 B

Chemical

SI (%)

SI (%)

Flowering

Harvesting

None

69.88 A

98.59 A

Yes

66.89 A

98.01 A

Corozal:

Table 4. Effects of spray program on yield parameters for the banana plant crops at Isabela and Corozal1,2,3 Isabela: Bunch weight -54.6% yield reduction.

Chemical

Fruits/bunch Hands/bunch

Fruits 1rst Hand

Fruits 2nd Hand

Bunch Weight (Kg)

Mean Fruit Weight (g)

None

118.89 A

7.80 B

19.30 A

16.96 A

11.21 B

94.75 B

Yes

125.30 A

8.30 A

19.36 A

17.47 A

24.72 A

198.55 A

Corozal: Bunch weight -53.8% yield reduction.

Chemical

Fruits/bunch Hands/bunch

Fruits 1rst Hand

Fruits 2nd Hand

Bunch Weight (Kg)

Mean Fruit Weight (g)

None

136.69 A

8.50 A

21.47 A

17.97 A

11.13 B

82.53 B

Yes

142.24 A

8.67 A

21.76 A

19.40 A

23.07 A

163.66 A

LS-means with the same letter are not significantly different at Îą â&#x2030;¤ 0.05 3 Bunch weight without rachis.

1

2 Average

of 6 replicates

First Banana Ratoon

Table 5. Spray Program for the control of BS on the first banana ratoon at Isabela1

Fungicide

Date

Cocktail Abound

May 26, 2011

Cocktail Abound

June 8, 2011

Cocktail Tilt

June 30, 2011

Cocktail Tilt

13 July, 2011

Cocktail Manzate

August 10, 2011

Cocktail Manzate

August 25, 2011

Cocktail Manzate

September 7, 2011

Bravo WS

September 27, 2010

Cocktail Abound

October 19, 2011

Cocktail Abound

November 3, 2011

Bravo WS

November 17, 2011

1 Fungicides

Total: 11 spray cycles Cocktail Tilt (propiconazole): Cocktail Abound (azoxystrobin): Cocktail Manzate (mancozeb): Bravo WS (chlorothalonil):

2 4 3 2 11

(Tilt, Abound and Manzate) were sprayed in an oil-water emulsion, meanwhile Bravo WS in a water-emulsion, based on manufacturer recommendations. Orchard Oil BVA#15 based on manufacturer recommendations.

Table 6. Spray Program for the control of BS on the first banana ratoon at Corozal1

Fungicide

Date

Fungicide

Date

Cocktail Abound

February 15, 2011

Cocktail Tilt

July 28, 2011

Cocktail Abound

March 1, 2011

Cocktail Tilt

August 12, 2011

Bravo WS

March 16, 2011

Cocktail Abound

August 25, 2011

Bravo WS

March 31, 2011

Cocktail Abound

September 12, 2011

Bravo WS

April 20, 2011

Bravo WS

September 29, 2011

Bravo WS

May 10, 2011

Bravo WS

October 14, 2011

Cocktail Abound

May 25, 2011

Bravo WS

October 29, 2011

Cocktail Abound

June 10, 2011

Cocktail Tilt

November 14, 2011

Bravo WS

June 24, 2011

Cocktail Tilt

November 28, 2011

Bravo WS

July 12, 2011

1 Fungicides

Total: 19 spray cycles Cocktail Abound (azoxystrobin): 6 Cocktail Tilt (propiconazole): 4 Bravo WS (chlorothalonil): 9

(Tilt, Abound and Manzate) were sprayed in an oil-water emulsion, meanwhile Bravo WS in a water-emulsion, based on manufacturer recommendations. Orchard Oil BVA#15 based on manufacturer recommendations.

19

Table 7. BS severity index on banana first ratoon at Isabela and Corozal Isabela: Chemical

SI (%) Flowering

None

41.04 A

Yes

39.97 A

Chemical

SI (%)

Corozal: Flowering None

55.81 A

Yes

48.65 A

Table 8. Effects of spray program on yield parameters of the first banana ratoon at Isabela and Corozal1,2,3 Isabela: Bunch weight -45.6% yield reduction.

Chemical

Fruits/bunch Hands/bunch

Fruits 1rst Hand

Fruits 2nd Hand

Bunch Weight (Kg)

Mean Fruit Weight (g)

None

118.46 B

7.93 A

18.57 B

17.29 A

13.85 B

116.76 B

Yes

144.21 A

8.93 A

21.41 A

18.55 A

25.46 A

176.16 A

Corozal: Bunch weight -33.2% yield reduction.

Chemical

Fruits/bunch Hands/bunch

Fruits 1rst Hand

Fruits 2nd Hand

Bunch Weight (Kg)

Mean Fruit Weight (g)

None

104.41 A

7.52 A

17.75 A

14.93 A

11.30 B

108.23 B

Yes

116.41 A

8.02 A

19.84 A

16.44 A

24.35 A

209.17 A

LS-means with the same letter are not significantly different at Îą â&#x2030;¤ 0.05 3 Bunch weight without rachis.

1

2 Average

of 6 replicates

Chemical Control

None Chemical Control

Conclusions:

§ Spray Program improved crop yield on bananas. § Chemical control: intensive and expensive. § Corozal: due to high inoculum pressure and persistant rainy period the use of protectant fungicides (e.g. mancozeb - not possible).

§

BS severity: Isabela: PC -54.6%, RC -45.6% yield reduction.

Corozal: PC: -53.8%, RC -33.2% yield reduction

Acknowledgment Dr. Raúl Macchiavelli Mr. Evelio Hernández Mr. Armindo Santiago.

Mr. Angel Cabán (Layo) Mr. Efraín Cancel Field Personnel at Corozal & Isabela Stations Program FIDTA: PRACTICES FOR THE CONTROL OF Black Sigatoka IN PUERTO RICO

Questions?