Mating disruption and pheromone control of Codling moth · Mating disruption and pheromone control...

Mating disruption and pheromone control of Codling mothLarry J. Gut

Department of Entomology, Michigan State University

X

female

gentle wind

What is the “normal” situation ?

eggs

gentle wind


eggs

gentle wind

Mating disruption is intended to stop this !!


eggs

gentle wind

Mating disruption is intended to stop this !!

HOW DOES IT WORK?

1. 1. Desensitization –– males cannot find calling females males cannot find calling females because prebecause pre--exposure to pheromone causes loss of exposure to pheromone causes loss of sensitivity in antennae or brain.sensitivity in antennae or brain.

Alternative models (explanations) for mating disruption:


1. 1. Desensitization –– males cannot find calling females males cannot find calling females because prebecause pre--exposure to pheromone causes loss of exposure to pheromone causes loss of sensitivity in antennae or brain.sensitivity in antennae or brain.


2. 2. Camouflage –– males cannot find calling females becausemales cannot find calling females becauseof interference from an atmospheric background of of interference from an atmospheric background of pheromone released from dispensers.pheromone released from dispensers.

Regardless of the way disruption is achieved, the common mode of operation is to:

• Dispense a large amount of sex pheromonewithin the crop

• Disturb the normal behavior of male insects

• Interfere with mating

• And hence reduce the incidence of larvae

SearchingMale

……. and pheromone traps are a useful means of assessing disruption treatments

Males can’t locate “calling females”

SearchingMale

Female

Trap serves as false female, thus males can’t locate standard trap

Trap

COMPETITIVEATTRACTION

NON-COMPETITIVEMECHANISMS

Desensitization

CamouflageConfusion, False-trail following

Male

Female

SearchingMale

Female

However, knowing more about the specific way it is achieved will guide us in:

•selecting a good formulation•using it in the best way

Attraction Not attraction

COMPETITIVEATTRACTION

NON-COMPETITIVEMECHANISMS

What evidence do we have supporting one mechanism over another

DISRUPTION MECHANISMS

What we know:

Companion insecticides are often required unless pest densities are low

Higher population densities areharder to disrupt

• Disruption outcomes are sensitive to pest density

• Male moths readily approach dispensers

00

100

Pheromone Dispensers Density

Male Catch

00 100

20

40

60

80

20 40 60 80

Competitive Attraction

Non-Competitive Disruption

What we know: Disruption profiles most often fit the prediction of competitive attraction

What are some of the key practical implications if disruption operates via competitive attraction

• Dispenser density should be high

• Distribution should be uniform, rather than clumped

• Lots of attractive point sources should provide the best disruption

0

20

40

60

80

100

0 25 100 250 500

% OFM Catch

( relative to check plots)

OFM (MRosso)

Point sources per Hectare

0

20

40

60

80

100

0 25 100 500 1000

% CM Catch

( relative to check plots)

Point sources per Hectare

CM (CPlus)

Uniform vs. clumped distributtion of dispensers

Low density approaches, such as Aerosol emitters

‘Puffer’

46-75% inhibition of CM captures

91-98% inhibition of OFM captures

For both pests, generally less impact than in comparable plots treated with hand-applied dispensers at label rates

And, generally a lack of measurable, added benefit, in terms of fruit protection

Isomate CTT Rate Experiment

(Brunner et al. WSU)

• 1,200 acres• 4 MD treatments• 4x40 acre blocks

Isomate C+ 400 d/ac

Isomate CTT 200 d/ac

Isomate CTT 100 d/ac

Isomate CTT 50 d/ac

Impact of dispenser density

0

50

100

150

200

250

CTT @ 50 ac

0

50

100

150

200

250

CM catch in plots treated with various rates of Isomate dispensers

CTT @ 100 ac

CTT @ 200 ac

C+ @ 400 ac

High populations

Low populations

CTT @ 50 ac

CTT @ 100 ac

CTT @ 200 ac

C+ @ 400 ac

0.0

0.4

0.8

1.2

1.6

CM damage in plots treated with various rates of Isomate dispensers

CTT @ 50 ac

CTT @ 100 ac

CTT @ 200 ac

C+ @ 400 ac

400 C Plus200 C Plus

200 CTT100 CTT

No pheromone

0.0

0.5

1.0

1.5

2.0 InteriorEdge

Mean % fruit injury

Higher point source densities provide better fruit protection; especially along field borders

High application rateson the edge

Reduce rates as you move into the interior

e.g, 300-500

e.g., 100-200

Edge is 30-40 meters

If applying 400 units/acre is too costly, reduce the numbers placed in the interior

Bad choiceBest choiceGood choice

Best approach for mitigating border

Whole-farm or Area-wide approach

Michigan area-wide mating disruption project

2 new regions

• 3 new areas in 2005;• 810 ha total

2004325 ha

2006

• 1130 ha total

Ridge

• Whole-farm approach to using mating disruption

• Reduction in CM pressure over the course of 3 yrs

Project highlights included:M

ean N

o. C

M/tra

p

2004 20052006

74% fewer CM captured in AW vs No-CMMD

• Reduction in fruit injury• Demonstration of the value of area-wide

Mean F

ruit Inju

ry (%

)

AW-CMMDBlock-CMMD

No-CMMD

• Reduced need for companion insecticides• Dramatic increase in the use of Disruption in MI

35% reduction

Mean Number Insecticide

Applications Targeting CM

Mean codling moths per trap + SEM

Number of point sources per ha (0.1 mg wax drops)

0

20

40

60

80

0 10000 20000 30000

a

b

c cdd

50%

79%87%

99%

Easy phase

Difficult phase

• Achieving outstanding disruption will be difficult and required the application of many attractive point sources

Machine-applied formulations

Lot’s of interest in:

MEC sprayable formulations

0

10

20

30

40

50

60

70

80

90

19-Jul 2-Aug 16-Aug 30-Aug 13-Sep

UTC

20-gm AI

100-gm AI

7/25

Mean moths/trap per week

Airblast applications yield unsatisfactory results

ca. 60% inhibition

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 3 4

Water control

Air-blast

Low volume

No. weeks post-spray

Pro

portio

n o

f traps c

atc

hin

g m

oth

s

Ultra-low volume improves performance (Knight and Larsen)

Figure adapted from: Knight, A.L. and T.E. Larsen. 2004. J. Entomol. Soc. Brit. Columbia 101: 79-86.

a

b

b

Photos courtesy of R. Hilton, OSU.

1-Aug 9-Aug 15-Aug 23-Aug 2-Sep 12-Sep

0

5

10

15

20

25

30

1-Aug 9-Aug 15-Aug 23-Aug 2-Sep 12-Sep

0

5

10

15

20

25

30

35

About 2-3 weeks of activity

Site 1

Site 2

Application:20 gm a.I./acre1.5 gal water/acreEvery row treated

Low volume approach is the most efficacious

• Even then, we consistently achieve:only ca. 70% disruption

for 2-3 weeks

Lure

Wax-paper strips

Flight tunnel investigations of attraction to sprayable pheromone

Treatments:

� Dilute CM sprayable

� Concentrated CM sprayable

FindingsDilute spray disrupted well for <2 days via camouflageConcentrated spray disrupted well for 1 wk via competition

Treatment Rainfall (mm)

I I* III III* V

1.35.67.6

ND 9.4S S ND 10.4S S S S ND 11.9S S S S ND 21.8

S S S S 22.4S S 87.4

* - Nu-Film-17 added; ND = No DataS - Significantly less capsules on field than control leaves (P < 0.05)

------------

43-76% ofcapsules lost

after 10 cm of rain

Microcapsules are washed off by rain

Deposition & Adhesion of fibers and flakes needs to be improved

• only 10-20% application efficiency

• with high percentage of those dislodged over time

2nd gen.

0 20 40 60

No disruptionFibersC Plus

0.3%

1.0%

Mean moth captures per trap

63% vs 95% inhibition

0.47%

0.27%0.47%

11% vs 67% inhibition

0.27%

1st gen.Machine-applied formulationsLevel of disruption variable:• Pest density• Number of dispensers actually on tree

Can we achieve “High performance”mating disruption ?

Codling moth

• Very few, if any, males caught in monitoring traps

• Same excellent disruption regardless of pest density

• Same excellent disruption without use of insecticides

MSU High-density wax formulation

0

10

20

30

40

50Control

Pheromone

0

20

40

60

80

100

Control

Pheromone

No mating of tethered

virgin females!

99% inhibition of traps!

“ High-performance” disruption of OFMMean OFM males /

treatment

% mating of OFM females

One application on April 24160 g pheromone A.I. / ha

4/29 5/13 5/27 6/10 6/24 7/8 7/22 8/5 8/19 9/2

5/10 5/24 6/7 6/21 7/5 7/19 8/2 8/16 8/30

0

5

10

15

Control CM:PE(high load)

CM:PE(low load)

CM Isomate

Results from Large-plot (2 ha) trials 2006

Mean CM males / treatment

90 % 90 % 92 %81 %

a

Combining high efficacy of Cidetrack CM with highpoint-source density

Focused on Cidetrack codlemoneonly which produced best results in both small and large plots

Cut these dispensers into 7 pieces of equal size for high-density deployment in the field

0 250 1,250 6,250 18,750

Number of Cidetrack pieces per hectare

0 1 5 25 75

Number of Cidetrack pieces per tree

which corresponds to:

Number of CM males per trap

Yes!! We can achieve high-performance disruption of CM; but, it takes a lot of point sources per unit area.

99 %92 %90 %

56 %

HighPerformance!

0

40

80

120

160

200

2007 efforts: Combine these advances

0

5

10

15

20

25

30

22-May 5-Jun 19-Jun 3-Jul 17-Jul 31-Jul 14-Aug 28-Aug

average codling moth catch/trap

MSU formulationNo pheromone

Isomate C+

x

RCBD with 5 replicates in 25 tree (0.1 ha) plots

Disruption measured with two traps baited with 0.1 mg lures in each plot and mating of tethered virgin females

2007 CM small-plot trials using a high point source (150/ha), wax-based formulation

LARRY’S MOST EXCELLENT ADVENTURE WITH PHEROMONES

On top of the world as

a bachelor in Wenatchee

End of

1st year

pheromone

research

95

91

92-93

94

The lonely disrupted years

Tolerance to pheromones occurs

Full-blown resistance

has developed

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are needed to see this picture.

Thank you and I would be happy to answer questions

Mating disruption and pheromone control of Codling moth · Mating disruption and pheromone control...

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