1

Research Update on Non-Antibiotic Control of Fire Blight

Ken Johnson, Oregon State University; Rachel Elkins, University of California Cooperative Extension; Tim Smith, WA State University Cooperative Extension

March 19, 2013

http://www.extension.org/organic_production

Tim Smith, WSU

Cooperative Extension

Ken Johnson

Oregon State

University

Rachel Elkins

University of California

Cooperative Extension

Fire Blight Control in Organic

Pear and Apple without

Antibiotics

Ken Johnson, Oregon State University

Rachel Elkins, University of California

Tim Smith, Washington State University

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This webinar is about fire blight

suppression without antibiotics:Antibiotics:

Streptomycin < 2014 NOP expiration (set by NOSB in 2011) *Oxytetracycline < 2014 NOP expiration *

*Industry has petitioned to re-instate normal sunset review process

Our focus: Floral infection in susceptible cultivars*

*Strategies and data shown are most applicable to

semi-arid production regions of the western U.S.

This webinar is not about:

Host resistance (ideal but longer-term goal)

Management of host susceptibility (nutrition)

Significance of

old cankers &

bloom temperature

CougarBlight

models this

A. Jones, APSnet

Pathogen

overwinters

here

This jump starts

the cycle

3

Materials we have chosen to focus on

for non-Antibiotic fire blight control Prebloom: Product effectivenessNOP-approved fixed copper poor to good

Early bloom:Bloomtime Biological (pears) poor to good

Lime Sulfur (and Fish Oil) (Apple) good

Mid- to full bloom:Blossom Protect (new in 2012) very good to excellent

Full bloom and beyondGowan Previsto excellent

(still needs EPA registration and NOP/OMRI approval)

Soluble

Copper

Fixed

copper

Biologicals

Lime Sulfur

Soluble

Copper

Systems Approach to non-antibiotic control

Questions:

• When does fire blight pathogen become active and does delayed dormant copper effect this pathogen activity?

• How does bloom thinning effect fire blight control?

• Integrated control: Can effective non-antibiotic control be achieved?

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Q1: When is the fire blight pathogen active in orchards?

Answered by „LAMP‟ assay that detects pathogen DNA:

Is the fire blight pathogen

in this bag of flowers?

+ -

< 1 hour

to get an

answer

Q2: Does delayed dormant copper effect pathogen activity?

• Delayed dormant oil plus

CuOH+CuOCl (6 lbs/A)

• Delayed dormant oil

Walk 1 Walk 2 Walk 3

Walk 1 Walk 2 Walk 3

Rachel Elkins

Pomology Farm Advisor

UC Lake County

In 2010-2012 we split

fourteen ~10-acre blocks

LAMP Surveys

California pear LAMP survey 2011

0

20

40

60

80

1-Apr 6-Apr 11-Apr 16-Apr 21-Apr 26-Apr 1-May 6-May

% F

low

er

sa

mp

les

po

sti

ve

fo

r

E. a

my

lov

ora

Oil alone

Copper + oil

Mid-bloom Full bloom Petal fall

California pear LAMP survey 2010

0

20

40

60

80

100

12-Mar 22-Mar 1-Apr 11-Apr 21-Apr 1-May 11-May 21-May

% F

low

er

sam

ple

s p

osti

ve f

or

E.

am

ylo

vo

ra

Oil alone

Copper + oil

Mid-bloom Full bloom Petal fall Petal fall 2

Walk

1

Walk

2

Walk

3

Walk

1

Walk

2

Walk

3

Overall probability of pathogen detection ~ 16%

Mid-bloom P(detect Ea) < 5%

Petal fall P(detect Ea) ~ 50%

P(detect Ea) in „Copper + Oil‟ ½ of „Oil alone‟

Does delayed dormant copper effect pathogen build-up?

5

Walk

1

Walk

2

Walk

3

Walk

1

Walk

2

Walk

3

Does delayed dormant copper effect pathogen activity?

Rachel Elkins and Steve Lindow have

obtained fruit finish data from all plots

No difference in Russet Severity among

the „Copper & Oil‟ and „Oil only‟ plots

Average

Russeting Russet Severity

Treatment1 (greater than 7%) (less than 3%)

Copper + oil 2.7 10.5 76.0

Oil alone 2.7 10.2 76.1

Summary of California LAMP Surveys

• When is the fire blight pathogen active in orchards?

Depends on orchard, but late (PF) is more the norm

• Does delayed dormant copper effect pathogen activity?

Yes, it delays time to when the pathogen is detectable (PF)

Think about Questions

on ‘LAMP’

and

‘Delayed Dormant Copper’

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Q: How does the bloom thinning material,

LIME SULFUR, effect fire blight control?

• As used for thinning, does LS provide a benefit to fire

blight suppression?

• Is LS bactericidal? If so, does it replace other fire

blight products in early bloom?

• Typical protocol: Spray lime sulfur @ king bloom open

then repeat in 3 days (70-80% bloom)

Apples

Q: How does bloom thinning effect fire blight control?

Replicated, inoculated orchard trials:

Golden/Gala 2009

0 30 60 90 120 150

Water

Lime sulfur & Fish oil 2.5X

BlightBan 2X then Oxytet 1X

Gala 2010

0 40 80 120 160 200

Golden Delicious 2011

0 40 80 120 160 200

Water

Lime sulfur & Fish oil 2X

Bloomtime 1X then Oxytet 1X

Gala 2011

0 20 40 60 80

Fire blight strikes per tree

Pathogen inoculated

after second LS+FO

Conclusion: Lime sulfur treatments results in fewer flowers to flowers

Lime sulfur directly suppresses

epiphytic pathogen population

Population size of E. amylovora

2

3

4

5

6

7

UTC LSFO

2%

LS

3%

LS

6%

LS

9%

Lo

g1

0 (

CF

U p

er

flo

we

r)

Golden D 4/29Golden D 5/2

Rome Beauty 5/7 Rome Beauty 5/10

Conclusion: Lime sulfur is bactericidal

Q: How does bloom thinning effect the fire blight pathogen?

One million cells

per flower

Ten thousand

cells per flower

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Lime sulfur directly suppresses

populations of biological agentsPopulation size of A. pullulans

2

3

4

5

6

7

UTC LSFO

2%

LS

3%

LS

6%

LS

9%

Lo

g1

0 (

CF

U p

er

flo

we

r)

Golden D 4/29Golden D 5/2

Rome Beauty 5/7 Rome Beauty 5/10

Population size of P. agglomerans

2

3

4

5

6

7

UTC LSFO

2%

LS

3%

LS

6%

LS

9%

Lo

g1

0 (

CF

U p

er

flo

we

r)

Golden D 4/29Golden D 5/2

Rome Beauty 5/7 Rome Beauty 5/10

Bloomtime Biological Blossom Protect

Conclusion: Delay biologicals to

after 2nd LS treatment

Q: How does bloom thinning effect biological agents ?

Think about Questions

on ‘Bloom Thinning’

- LS thins flowers

- LS is bactericidal & fungicidal

Early bloom

Full bloom

to

Petal Fall

Q4: Can effective non-antibiotic control be achieved?

‘Integrated control’

Combining a stigma product with a

floral cup product improves control

Antibiotic approach:

e.g., Bloomtime Biological then

Oxytetracycline

Non-antibiotic approach:

e.g., Bloomtime Biological then

Blossom protect PEARS

e.g., Lime sulfur & fish oil then

Blossom protect APPLES

very good to excellent control

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Gala 2010

0 40 80 120 160 200

Water

Lime sulfur & Fish oil 2X

LS+FO 2X then Blossom Protect 2X

Bloomtime 1x then Oxytet 1X

Streptomycin 2X

Gala 2011

0 20 40 60 80

Golden Delicious 2011

0 40 80 120 160 200

Water

Lime sulfur & Fish oil 2X

LS+FO 2X then Blossom Protect 2X

Bloomtime 1x then Oxytet 1X

Streptomycin 1X

Gala 2012

0 40 80 120 160 200

Fire blight strikes per tree

Integrated control

Lime sulfur plus fish oil

Followed by new yeast product

Yeast cells

on nectary

of

pear flower

sampled

near petal

fall

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Blossom Protect YEAST colonizes both

stigmas and floral cup

0

25

50

75

100

5/6

5/10

5/14

5/18

Flo

ral

cu

ps c

olo

niz

ed

(%

)

Number of yeast

cells on each floral

cup was ~ 5000

Yeast colonized

nearly 100% of

floral cups

Bloomtime bacteria does well on stigmas

but not on floral cup

Blossom Protect is an excellent

colonizer of flowersOR: Incidence of BP on Pear

0

25

50

75

100

Control

(untreated)

BP + Buffer A

@ 20%

BP + Buffer A

@ 80%

BP + Buffer A

@20% & 80%

Inci

de

nce

(%

)

OR: Incidence of BP on Apple

0

25

50

75

100

Control

(untreated)

BP + Buffer A

@ 20%

BP + Buffer A

@ 80%

BP + Buffer A

@20% & 80%

Inci

de

nce

(%

)

CA: Incidence of BP on Pear

0

25

50

75

100

Control

(untreated)

BP + Buffer A

@20%

BP + Buffer A

@80%

BT @30%,

70%; BP@ FB

Inci

de

nce

(%

)

WA: Incidence of BP on Apple

0

25

50

75

100

Control

(untreated)

BP + Buffer A

@ 20%

BP + Buffer A

@ 80%

BP + Buffer A

@20% & 80%

Inci

de

nce

(%

)

Sampled between

FB and PF

Sampled mid-

June

Potential drawback of Blossom Protect:

increased russeting of fruit surface

Russet index on apple cv. ´Santana´ 2008 and 2010 after Blossom Protect (BP). Numbers 1-4 represent timing of applications.

Multiple applications and wetter conditions during & after bloom raise the concern

Evidence to date is 2-3 applications in semi-arid regions (e.g., central WA) is safe

Data from Stefan Kunz 2011 – German scientist and inventor of Blossom Protect

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- When to apply

- Availability

- Drawbacks

Think about Questions about

the ‘YEAST’

Soluble Coppers -- Intended as bloom and petal fall treatments --

• Gowan Previsto (pending registration)

– Copper sulfate in a carrier that reduces phytoxicity

– Extensive fruit finish testing (Smith, Hubbard, Sugar)

– “Expected ~July, 2013. Components of the

formulation have been accepted as organic”

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Copper in organic acid products

contain less metallic copper

• Rapidly absorbed onto the plant

• Systemic action

• Long lasting residual

Company literature

Low phytotoxicity

Long residual

Tightly absorbed 0

10

20

30

40

50

60

NuCop 50W Kocide 2000 Kocide 3000 Phyton 27 AG

Previsto

% M

eta

llic

co

pp

er

Can effective non-antibiotic control be achieved?

Yes, via „integrated control‟:

… utilizing delayed dormant, fixed copper in orchards with history of fire blight

… in apples, using lime sulfur to thin bloom and delay pathogen „build-up‟ in flowers

… in pears, using a bacterial biocontrol agent to delay pathogen „build-up‟ in flowers

… utilizing the yeast Blossom Protect near full bloom to protect floral cup

… utilizing a soluble copper at later bloom to

substitute for oxytetracycline

What are the cautions and risks of non-

antibiotic control compared to antibiotics?

Control Practice

EPA & NOP

approved

Grower

experience

FB control at

orchard scale

Cost

Fruit finish

Delayed dormant

copper

Lime sulfur (+ fish oil)

thinning

WA WA

YEAST -

Blossom Protect

2012 little little ~2X higher Safe in West for

apples but data

limited

PREVISTO -

bloom-safe copper

2013? not yet not yet ? Safe in West for

apples but data

limited

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Questions?

- delayed dormant, fixed copper

- lime sulfur effects on fire blight pathogen

- integrated, non-antibiotic control

- the yeast product

- copper materials during bloom

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