Disease management in organic grape

production

Annemiek Schilder

Michigan State University East Lansing, Michigan

"Organic agriculture is an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony."

Organic Trade Association

"Organic food is produced according to certain legally regulated standards. For crops, it means they are grown without the use of conventional (synthetic) pesticides, artificial fertilizers or sewage sludges. Also, at all levels, organic food is produced without the use of genetically modified organisms."

Wikipedia

• Regulations for crop production and handling provided by the USDA National Organic Program

• Farms must be certified by accredited certifying agent based on farm plan and on-site inspection

• 3-year transition period before food can be labeled as organic

• Exempt from certification if sales < $5,000/year

List of products approved for use in organic crop production:

Organic Materials Review Institutehttp://www.omri.org

Important grape diseases in the Midwest

• Downy mildew (Plasmopara viticola)

• Powdery mildew (Uncinula necator)

• Phomopsis cane and leaf spot (Phomopsis viticola)

• Botrytis bunch rot (Botrytis cinerea)

• Black rot (Guignardia bidwellii)

• Crown gall (Agrobacterium tumefaciens)

• Virus diseases (TRSV, ToRSV, GLRaV)

Non-chemical disease management options

• Select resistant or less susceptible varieties

• Select a suitable site with good airflow and drainage

• Prune and train vines to reduce canopy density

• Leaf removal to decrease humidity and increase sunlight penetration (especially for bunch rot)

• Prune out and remove diseased plant parts

• Clean planting material from reputable nursery

• Minimize plant stress and injury

Organic fungicide options for grapes 1) Copper, sulfur, lime sulfur (not all formulations)

2) Potassium bicarbonate salts (Armicarb, Kaligreen, Milstop)

3) JMS Stylet Oil (paraffinic oil)

4) GantecGold (neem oil)

5) Sporan (thyme oil, rosemary oil, clove oil)

6) Serenade (Bacillus subtilis – biocontrol agent)

7) Sonata (Bacillus pumilis – biocontrol agent)

8) OxiDate (hydrogen peroxide)

9) Regalia (giant knotweek extract)

10) Blightban (Pseudomonas fluorescens)

All of these are contact materials/protectants

Powdery mildew (Uncinula necator)

0 10 20 30 40 50

Multi-Sovran

Flint/Elite

AQ10 + NuFilm

Armicarb

Serenade

Untreated

Powdery mildew severity

% Total leaf area infected

Vidal, 2000

a

d

bc

b

d

Ampelomyces quisqualis c

Evaluation of organic fungicides for powdery mildew control

0

5

10

15

20

8/4/9

9

8/11/9

9

8/18/9

9

8/25

/99

9/1/

99

ControlArmicarbArmicarb/OilStylet oilNova

% L

eaf

are

a a

ffect

ed

Foch, 1999, Sutton’s Bay

0

10

20

30

Untreat

ed

Sanita

tion

Nufilm

Stylet

Oil

Oxidat

e

Kaligr

een +

NuF

ilm

Serena

de +

NuF

ilm

Sanita

tion

+ Sere

nade

+NF

Dith/A

b/Zir+

Nov

Efficacy of organic fungicides for control of powdery mildew in ‘Niagara’ grapes, Fennville, MI, 2009

%

Leaf

are

a in

fect

eda

ab

bc

cc

cd

d d

d

0

10

20

30

Untreat

ed

Serena

de lo

w

Serena

de hi

gh

Sonat

a hig

h

Ser/S

on/K

al/JMS

Sonat

a low

Tetra

sul/S

erena

de

Serena

de/S

onata

Serena

de/K

aligr

een

Dith/A

b/Zir+

Nov

Efficacy of organic fungicides for control of powdery mildew in ‘Niagara’ grapes, Fennville, 2009

%

Leaf

are

a in

fect

ed

a

bcb

b

c c c c c c

All treatments: + NuFilm

Efficacy of different fungicide programs in controlling powdery mildew on leaves of ‘Chancellor’ grapes, Fennville, 2008

3

0

20

40

60

80

100a

%

Leaf

are

a in

fect

ed

b

b

cc

Downy mildew (Plasmopara viticola)

0

10

20

30

40

Untreated Serenade Penncozeb

% L

eaf

area

dis

ease

d

Downy mildew severity

b

c

aVignoles, 2001

0

5

10

15

20

Untreated Compost tea Pristine

% L

eaf

area

dis

ease

dDowny mildew severity

bc

a Niagara, 2002

Efficacy of organic fungicides for control of downy mildew in ‘Niagara’ grapes, TNRC, Fennville, 2008

2

0

20

40

60

80

100

a

%

Leaf

are

a in

fect

ed

b

bbc

bc bc

c c c

d d

e e

Efficacy of different fungicide programs in controlling downy mildew on leaves of ‘Chancellor’ grapes, TNRC, Fennville, 2008

3

0

20

40

60

80

100a

%

Leaf

are

a in

fect

ed

bb

cc

0

10

20

30

40

50

Efficacy of organic fungicides for control of downy mildew in ‘Niagara’ grapes, Fennville, 2009

%

Leaf

are

a in

fect

eda

b

d

c

cd

bc

d d

e

0

10

20

30

40

50

Efficacy of organic fungicides for control of downy mildew in ‘Niagara’ grapes, Fennville, 2009

%

Leaf

are

a in

fect

eda

b

cbc

d

c c c c c

Botrytis bunch rot (Botrytis cinerea)

0 2 4 6 8 10

Van-Flint-Van-Flint

Flint-Van-Flint-Van

Elevate (4x)

Serenade (4x)

Vangard (2x)

Rovral (4x)

Untreated

Botrytis bunch rot severity

% All berries infected

Vignoles, 2000

ab

bc

a

bc

cd

cd

d

0 20 40 60

Pristine 1.2 lb 4x

Serenade 6 lb 4x

Oxidate 1:100weekly

Untreated

Botrytis bunch rot severity

% All berries infected

Aurore, 2001

a

a

a

b

Black rot (Guignardia bidwellii)

0 0.5 1 1.5 2

Flint/Elite

Armicarb

Serenade

Untreated

Black rot severity

% All berries infected with black rot

Vidal, 2000

a

b

b

b

Black rot severity

% Berries with black rot symptoms

0 5 10 15 20

Dith-Elite

Armicarb

Untreated

Concord, 2001

Efficacy of organic fungicides for control of black rot in ‘Niagara’ grapes, TNRC, Fennville, 2008

1

0

20

40

60

80

100

a

%

Ber

ries

infe

cted

ghijk

k

abc

hijkhijk

ghijfghiefgh

defgdefg

defcdecdebcd

Phomopsis cane and leaf spot (Phomopsis viticola)

0 0.5 1 1.5

Multi-Sovran

Flint/Elite

Armicarb

Serenade

Untreated

Phomopsis rachis lesion severity

% Total rachis area infected

Vidal, 2000

a

c

c

b

b

0 1 2 3 4 5

Multi-Sovran

Flint/Elite

Serenade

Armicarb

Untreated

Phomopsis fruit rot severity

% All berries infected

Vidal, 2000

a

d

cd

bc

c

0

10

20

30

40

50

60%

Rac

his

infe

ctio

n

Efficacy of organic fungicides for control of Phomopsis in ‘Niagara’ grapes, TNRC, Fennville, 2009

a

b b

bcbc

c c c c c c c c c

Dormant sprays(copper, sulfur, lime sulfur)

Not all products OMRI-listed

0

10

20

30

40

% R

ach

is a

rea

infe

cte

d

a

bb

bb

Approximate product cost per acre:

$5 $65$6 $73

b

$20

Vignoles, 2004

Effect of single dormant sprays on Phomopsis

Effect of OMRI-listed dormant sprays on Phomopsis

0

10

20

30

40%

Be

rrie

s in

fect

edNiagara, 2006a

b

c c

0

4

8

12

Effect of single dormant sprays on black rot

% B

err

ies

infe

cted

b

Niagara, 2004a

a ab ab

b

c

Effect of single dormant sprays on powdery mildew

0

2

4

6N

um

be

r of

be

rrie

s in

fect

ed Chardonnel, 2005

a

b

b

Conclusions

Disease control in organic vineyards is possible, but there are fewer fungicide options than in conventional production and these are generally not as effective as the best conventional fungicides – therefore they may need to be applied more often

All products are protectants: need to be applied

before infection and are susceptible to wash-off

by rain

Promising products: Serenade, Sonata, Stylet Oil,

Armicarb, Kaligreen

Organic growers need to rely more on site selection,

resistant cultivars, canopy management to reduce

humidity and increase sunlight penetration, and

pruning to remove diseased plant parts

Conclusions

Dormant sprays are a good option (before budbreak)

to reduce overwintering inoculum

NuFilm (or similar sticker/extender) should be used

A good resource for organic grape production

is ATTRA (www.atra.ncat.org)

Other useful resources:

- Grape IPM Pocket Scouting Guide

- Midwest Small Fruit and Grape Spray Guide

- MSU Fruit Management Guide (E-154)

- MSU Grape website: www.grapes.msu.edu

Conclusions