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Mating disruption and pheromone control of Codling mothLarry J. Gut
Department of Entomology, Michigan State University
X
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:
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.
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.
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.
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.
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.
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.
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.
Alternative models (explanations) for mating disruption:
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.
Alternative models (explanations) for mating disruption:
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.
Alternative models (explanations) for mating disruption:
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.
Alternative models (explanations) for mating disruption:
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
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
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
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