Document ID: EPA-HQ-OPP-2005-0061-0187
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-10-20T04:00Z

Summary of Assessment of EPA-BEAD Grower Analysis of Azinphosmethyl

Jay F. Brunner

Washington State University

Tree Fruit Research and Extension Center

1100 N. Western Ave.

Wenatchee, WA 98801

Phone: 509-663-8181

E-mail:   HYPERLINK "mailto:jfb@wsu.edu"  jfb@wsu.edu  

Abstract: The three scenarios for replacement of azinphosmethyl (AZM) in
western apple production includes a substitution with phosmet (scenario
#1), substitution with neonicotinyl insecticides (NNI) and an insect
growth regulator, novaluron (scenario #2), and use of pheromone (mating
disruption) with a single AZM rescue treatment (scenario #3). The first
two scenarios are logical and represent possible programmatic directions
western apple growers might follow.  However, scenario #3 is not a
logical option, especially to replace a 3-application AZM program and
should not be considered by the EPA as an alternative when making
decisions about continued use of AZM.  There are serious problems with
the economic analysis, primarily associated with three factors; 1) the
cost of insecticides does not represent realistic costs to the growers ,
2) it is in appropriate to use an average per acre rate of products when
considering substitution programs for AZM, and 3) there is no additional
cost for an additional application in scenarios #1 and #2.  Other
assumptions like the complete shifting of injured fruit from fresh to
processing with growers benefiting somewhat from reduced income may no
longer be valid since processors are as strict as the fresh market in
rejecting lots with codling moth (CM) injury.  The use of NNI and
novaluron will most likely result in the eventual disruption of spider
mite biological control necessitating the application of specific
miticides on a significant proportion of acreage, thus increasing grower
costs.  The argument that some growers will switch from conventional to
organic apple production is likely true if AZM was completely eliminated
as an option for apple growers.  However, there is likely to be no
increased in net revenue from this transition based on the increased
costs of organic programs and lower returns for organic fruit over the
last 3-4 years.  

General comments relative to the EPA 2005 Grower Impact Assessment of
Azinphos-methyl Use on Apples (DP 307589)

Spectrum of pests (western US) controlled by AZM.

Leafrollers, San Jose scale and aphids are listed in the report as being
targets of AZM.  In Washington leafrollers are NOT a pest controlled by
azinphosmethyl (AZM) and likely not used as a primary control of LR in
CA or other western states. San Jose scale may be suppressed by AZM
(second codling moth cover spray) but it is not relied upon for the
primary means of control of this pest.   Aphids are NOT controlled by
AZM.  

Use of pheromones (mating disruption-MD) in WA and other locations.

Between 2000-2004 about fifty percent of apple acreage was treated with
pheromones for CM control (CMMD) in WA. The acreage treated with CMMD in
WA in 2005 is estimated to be nearly 65% of the apple acreage (120,000
acres treated). Most pear acreage in CA is treated with CMMD but the
percentage apple acreage treated with pheromone is likely much lower. In
OR there is some use of CMMD in apple but the percent area treated is
likely much lower than in WA. 

Cost of CMMD is a major concern in the western US, as it is elsewhere. 
The high cost has resulted in growers using less than full rates, which
compromises the full effect of the technology and as a result requires
increased use of supplemental insecticides to achieve acceptable
commercial levels of crop protection.

Very few orchards will be able to reduce CM populations to levels where
CMMD will be a stand-alone control for CM.  It is possible with a
concerted effort to reduce CM densities to levels where lower rates of
pheromones can be used with one or two supplemental insecticides and
this is a common management program in many WA orchards.  

Alternative insecticides for CM control. 

The use of kaolin clay (Surround) for CM control is not a practical
approach.  Seasonal use of this product results in increased spider mite
problems and it also interferes with biological control of leafminers.  

The statement that CM granulosis virus (CpGv) is not effective against
first generation CM is not true. CpGv is effective against CM in the
first generation and can be a very good fit in an integrated pest
management program that incorporates bio-pesticides.  The use of CpGv in
the second CM generation makes sense where highly effective larvicides
and ovicides are used against in the first CM generation. CpGv is best
used in conjunction with CMMD where it will provide suppression of
resident CM population. The negatives associated with use of the CM
virus in the second CM generation are high temperatures and high UVL
intensity, both of which degrade the virus.  

Other alternatives for CM control not listed in the EPA-BEAD review
include methoxyfenozide, mineral oil and pyriproxyfen. All of these
products are considered to have as high or higher efficacy than kaolin
against CM with fewer negative side effects.  

Assumptions of statements relative to the use of AZM in western states.

In the Pacific Northwest switching to the use of phosmet is not the most
likely scenario that would occur if AZM were not available.  Increased
use of phosmet would likely occur if AZM was no longer available but it
is more likely that there would be a greater shift to newly registered
alternatives due to the lack of the industries confidence in phosmet as
an effective CM control and the cost of phosmet relative to newer
insecticides that might be perceived as more efficacious or hold
additional value in the control of other pests. 

On average the substitution of 4 application of phosmet for 3
applications of AZM is a reasonable model to use in this kind of
analysis, however, in some high-pressure situations (15-20% of orchards)
three applications of AZM is not sufficient to achieve acceptable levels
of crop protection and therefore four applications of phosmet would not
be sufficient to achieved acceptable control of CM. Using average usage
patterns always represents a problem in dealing with other orchard
situations that have high than average pest pressures and thus would not
be able to achieve acceptable control with the “average” use of
products.  

Diversion of CM injured fruit from the yield loss category to the
quality reduction category. 

Processors have become almost as averse as fresh markets for acceptance
of CM injured fruit.  Therefore, the concept of diverting injured fruit
into processing is not a very rational alternative given current
constraints.  CM injured fruit would more likely be discarded (therefore
reducing yield not shifting yield to a processing category) with NO
value to the grower. The EPA-BEAD report does note that if infestation
rates were too high in processor lots these would be rejected.  While
this might have a greater impact on the eastern growers it is not
without significant impact on the western apple growers.  In addition
the value of processing fruit for western growers, especially fruit, is
way below the cost of production and thus any diversion to processing
only reduces economic loss.  

Comments relative to use of neonicotinyl insecticides in western
orchards.

The use of two applications of neonicotinyl insecticides  (NNI) is an
acceptable alternative to replacement of AZM in many but not all WA
orchards.  WSU recommends use of only two NNI in a year but these should
be used against the same generation of CM.  The use of NNIs is
complicated by availability of NNIs that are effective against other
pests (primarily aphids) that could be used at a time CM is active and
therefore selected for resistance even though it is not the primary
target of the treatment.  The use of two NNIs in one season would not
likely increase spider mite populations in treated orchards in one year,
however, there is enough evidence in recent literature and from our
experience to suggest that with other perturbation factors present in
apple orchards it is likely that the long term use of more NNIs will
lead to increased problems with spider mites (Beers EH, Brunner JF,
Dunley JE, Doerr M, Granger K. 2005. Role of neonicotinyl insecticides
in Washington apple integrated pest management. Part II. Nontarget
effects on integrated mite control. 10pp. Journal of Insect Science,
5:16, Available online: insectscience.org/5.16). Increased problems with
spider mites would result in the need to apply more specific miticides
than has been true historically in WA. In addition, the use of NNIs with
novaluron could lead to stimulation in spider mite problems (E. H.
Beers, personal communication). There is also evidence from eastern
apple orchards novaluron can result in increased spider mite problems. 

Comments on use of novaluron.  

The use of novaluron could reduce costs of leafroller control and
offset, to some extent, the expense of the second scenario, but there is
only limited experience using this product in commercial orchard
situations and preliminary evidence suggests that it will add to the
perturbation of spider mite biological control.

Specific Comments relative to the three proposed scenarios for AZM
replacement. 

First Scenario.

The assumption of a substitution of phosmet for AZM is not the most
likely shift that would take place in WA orchards simply because phosmet
is not perceived as an effective control for CM.  However, for the sake
of this analysis it is not an unreasonable scenario to examine.  

Prices used for insecticides in the EPA-BEAD analysis are not what WA
growers would likely pay.  Based on retail prices (see table below) the
cost of AZM is $12.41 per pound. Many growers using AZM at a rate of 3
pounds if used only one time but under a three-application program only
2 pounds per acre would be used so the cost per application would be $25
per acre ($37 per acre for a three pound application).  A
three-treatment program of AZM would cost the grower $75 per acre.  

Phosmet (Imidan) costs about $8.75 per pound (see table below).  Growers
in WA use the maximum rate allowed for CM control, which is roughly 5
pounds.  Thus, the cost per acre for a phosmet application would be $44
(5 pounds * $8.75/lbs.).  Therefore a replacement program of phosmet (4
applications) would cost $176 per acre versus $75 per acre for a 3 AZM
application program.  In addition, there would need to be added the
extra cost of an application of phosmet ($20 per acre) since there is an
assumption of one more treatment per acre.  The cost of this to the
grower in the west would likely be a real increase since trips through
the orchard are not as common as occurs in eastern apple orchards. 
Adding the cost of an extra application to the phosmet substitution
program would make it $196 per acre compared to $75 per acre for AZM, or
a difference of $121 per acre.  

Table of information based on expected rate used for CM control and
estimated cost per acre based on high label rate for each product.  

Prices based on 2005 retail prices from Wilbur-Ellis Company.  Actually
prices paid for these products would likely be 10-20% lower than shown
here but the relative cost would remain the same.  

It appears in the EPA-BEAD analysis the average rate of an insecticide
from NASS surveys is used to help determine the cost of a treatment
scenario.  There is a logical flaw in this reasoning.  Growers do not
use an average rate for an insecticide treatment.  If they are going to
control CM they will use the most effective rate, usually the highest
rate on the label.  When comparing AZM with alternatives in an analysis
of this kind the most efficacious rate for CM control for each
insecticide should be used, not the average rate from a national survey.
 See the table above for the rates (formulated product) that would most
likely be used in WA orchards for control of CM.  

The cost information from Table 7 in the EAP-BEAD analysis indicates
that using the AZM alternative, phosmet, in the first scenario would
cost $60 per acre and that the AZM would cost $42 per acre.  Based on
more realistic prices for these products the cost of the phosmet program
should have been $196 (including the cost of an extra application)
compared to $75 per acre for AZM.  Therefore the phosmet program is 2.6
times the cost of the AZM program very close to the 2.5 used in the
EPA-BEAD report.  This is only a small difference but the total cost of
insect control is much higher than predicted given the scenario being
analyzed.  

Second Scenario. 

The products used in the second scenario as an alternative CM control
program for AZM represents a possible, though maybe not the most
logical, program for WA growers.  Even so the assumptions used in the
report are flawed based primarily on the prices of the products. 

Novaluron is an insecticide that has been used for only one season in
WA.  Novaluron is priced at $1.70 per ounce and 32 fl. ounces (or more)
are used for CM control in WA orchards.  Thus, the cost per acre is $54
not $20 as reported in Table 7 of the EPA-BEAD analysis.  Since there is
no data on novaluron use in apples prior to this report either the high
label rate should have been used or the typical label rate from research
trials should be used, that is the 32 fl. ounces per acre. 

Acetamiprid is used at a rate of 3.4 ounces for CM control in WA as a
replacement of one AZM treatment.  The cost of an application of
acetamiprid would therefore be $52 per acre. Thiacloprid is used at a
rate of 6 fl. ounces per acre for CM control at cost of $8.42/fl oz,
which results in a cost of $50 per acre per application. The rates used
for the NNIs should be as shown in the table above.  When the NNIs are
used for aphid control the rates used are much lower (about half)
compared to those used for CM control.  Therefore it is inappropriate to
use an average rate per acre in NASS or other use surveys for
determining costs of CM control programs. 

The current best estimate for WA is that about 65% of apple growers are
using CMMD of one kind of another.  The lowest cost for this technology
is about $100 per acre for a full use rate plus $15-20 per acre for
application. A much more realistic second scenario should include CMMD
at half to three-quarter the full field rate for at least 50% of the
acreage treated plus the cost of the alternative insecticides. This is
the program that is currently followed for uses of AZM and is a much
more realistic assessment for the economic cost of CM control programs
in WA. Other products that could likely be used in the second scenario
include methoxyfenozide, pyriproxyfen, mineral oil, and CpGv (CM virus),
all likely in conjunction with CMMD. 

The cost information from Table 7 in the EAP-BEAD analysis indicates
that using the AZM alternatives in the second scenario would cost $105
per acre. However, based on real prices and rates the program would cost
$212 per acre (acetamiprid-$52 + thiacloprid-$50 + two novaluron-$110). 
Like the first scenario the cost of an application ($20) should be
included, putting the total cost to $234 per acre. The second scenario
would therefore be about 3.1 times more expensive than the AZM
3-application program. The pest control cost increase would be $162 per
acre not the $63 per acre stated in the EPA-BEAD analysis. 

The EAP-BEAD analysis assumes that no yield or quality losses would
accompany the use of AZM alternatives in the second scenario. However,
there is really not sufficient commercial experience to confidently
claim that there would not be losses of yield or quality.  Evidence from
numerous recent research field trials would suggests that all the
alternative products used in the second scenario are close to AZM in
control of CM but none provide an equal level of crop protection as AZM.
 In several years of field trials in WA, AZM under high-pressure
situations provided an average of 94.2% reduction in fruit injury
relative to the untreated control.  Acetamiprid and thiacloprid provided
82.2 and 71.0% reduction in fruit injury, respectively (Brunner JF,
Beers EH, Dunley JE, Doerr M, Granger K. 2005. Role of neonicotinyl
insecticides in Washington apple integrated pest management. Part I.
Control of lepidopteran pests. 10pp. Journal of Insect Science, 5:14,
Available online: insectscience.org/5.14.). Some of the differences in
lower efficacy are related to experiments where lower rates were used in
initial trials, especially with thiacloprid.  However, there does seem
to be an inherent weakness in these two NNI products relative to AZM in
field tests where coverage and timing of treatments is precise. How
these differences would be expressed in commercial orchards has yet to
be determined but the very best scenario is that there would be no loss
in yield.  It is possible that operational factors, spray coverage and
timing issues, would reduce efficacy of commercial applications of the
NNIs and novaluron relative to AZM.  Excellent coverage of the target is
required for each of the alternative products because they have very
little or no contact activity. When using an IGR like novaluron timing
must be exact and is different from AZM so there is an adaptive period
while growers learn how to use new products.  Taking these factors
together it is likely that some yield losses could occur as new
technologies are implemented in apple IPM systems.  

In a three-year study where AZM alternatives were compared with an AZM
(conventional) program there were no differences in the cost of controls
or in the level of fruit loss due to CM injury.  These studies were
conducted in 15 grower orchards throughout WA and growers applied
treatments.  The key difference in this study and scenarios offered by
the EPA-BEAD report is that all the orchards were treated with
half-rates of CMMD (primarily Isomate C-plus) and AZM and
AZM-alternatives were applied as supplements.  In addition, most of
these orchards started out with very low CM populations and thus the
study primarily points out that it is possible to achieve adequate
control of CM over three years when starting at these low pest
populations levels.  This study should not be used as a typical
representation for all WA apple orchards (see the attached report on
this project below). 

Most effective specific miticides cost $50-60 per acre. The increasing
evidence that use of NNIs and novaluron could increase spider mite
problems resulting in the use of miticides on an additional 20% of apple
acreage in WA suggests that these costs should be added to the AZM
alternative program in the second scenario. It would be reasonable to
add at least $15 per acre to the second scenario to take into account
for the need to control spider mites.  

The use of novaluron could reduce costs of leafroller control and offset
to some extent the increased expenses caused by spider mites control of
the second scenario.   Since there is only limited experience in
commercial orchards with this product, and preliminary evidence suggests
that it will add to the perturbation of spider mite biological control,
the reduced costs of leafroller control would probably be neutralized by
the increased cost of spider mite control.

Third Scenario. 

In reality this scenario is NOT a comparison that is appropriate for an
orchard requiring 3 AZM applications to control CM. The third scenario
would only be appropriate for a small proportion of WA growers, maybe
10% of the acreage, and these growers would not have been using 3 AZM
sprays prior to adopting CMMD.   Any orchard requiring 3 AZM
applications could not achieve acceptable control of CM using CMMD plus
one “rescue” AZM application.  Therefore, all the analyses conducted
under this scenario would seem to be inappropriate.  

Evidence from early work on CMMD use in WA apple orchards suggests that
if used as a stand-alone technique it would not be able to provide
adequate CM control in many orchards.  In the paper by Gut and Brunner
(Gut, L.J. and J.F. Brunner. 1998. Pheromone-based management of codling
moth (Lepidoptera: Tortricidae) in Washington apple orchards. J. Agric.
Entomol. 15(4): 387-406.) 2 of the five orchards using CMMD as a
stand-alone technology showed a serious increase in CM populations and
crop (yield) loss when compared to a conventional program (see below
page 392 from the publication).  Other evidence from a non-peer reviewed
report (see Oregon State Horticulture Proceedings article below - page
99) also shows that CMMD alone does not provide adequate control where
CM densities are high. A high CM pressure orchard was described as
having moth captures (non pheromone treated orchard) greater than 50
moths per trap, use of 3-4 cover sprays, and greater than 1.5% crop loss
at harvest (Gut, L.J. and J.F. Brunner. 1996. Mating disruption as a
control for codling moth in Washington apple orchards. Wash. State Univ.
Tree Fruit Research and Extension Center Info. Series No. 1, March 1996.
The Good Fruit Grower, Yakima. 8 p.).  All these evidences plus grower
experience in WA strongly indicates that the third scenario is not a
realistic alternative for CM control.  

The EPA-BEAD assumption that there would be no yield or quality losses
in the third scenario is not supported by experience.  It might be
possible to have no additional yield losses in the first or second year
of a program like the third scenario but it is very likely that over
time yield losses would equal or exceed that experienced in the first
scenario.  While there is historical evidence to show that pheromones
plus AZM when used in an areawide program can reduce the need for AZM
applications from ca. 3 to less than less than one, it required 3 years
to achieve this level of AZM reduction (Brunner J.F., S. Welter, C.
Calkins, R. Hilton, E.H. Beers, J.E. Dunley, T. Unruh, A. Knight, R. Van
Steenwyk and P. VanBuskirk. 2002. Mating disruption of codling moth:  a
perspective from the Western United States. In: Witzgall, P., B.
Mazomenos and M. Konstantopoulou, editors. IOBC WPRS Bulletin Vol.
25(9): 207-215. Samos, Greece: OPBC WPRS.). In most situations replacing
3 AZM applications with a full rate of pheromone plus one AZM would lead
to an increase in yield loss of 0.5-1.0% the first year and it would
likely increase more in following years in many orchards.  While it is
possible to achieve acceptable commercial control of CM with pheromones
plus one or two insecticides, even AZM alternatives, this would occur
where CM populations have been driven to, or initially were at, low
levels.  

A more appropriate alternative scenario, one that would be an
organic-like approach, would include pheromones plus methoxyfenozide,
spinosad, oil and virus.  Such a program would avoid the perturbation of
spider mite biological control experienced in the second scenario but
would also be subject to high insecticide costs and yield losses similar
or greater than in first scenario. 



Building a Pheromone-based Multi-tactic Pest Management

System for Western Orchards

Areawide II Demonstration Project Report

Mike Doerr, Jay Brunner, Elizabeth Beers, John Dunley and Vince Jones

Washington State University 

Tree Fruit Research and Extension Center 

Wenatchee, WA

Objective 1.1	Evaluate CMMD programs that replace supplemental controls
of organophosphates with selective insecticides.

Objective 2.1	Evaluate/compare biological control in orchards using
mating disruption integrated with other selective tactics.

Project Title 	Implementation of a non-organophosphate program to
supplement a pheromone-based IPM program in apple. 

PI(s)	Jay F. Brunner, Elizabeth Beers, John Dunley, Vince Jones

Abstract 

Both SOFT and CONV treatment regimes were able to maintain injury from
CM at a very low level across the AWII project, even in the face of
increasing CM pressure throughout most of the growing areas of
Washington State. CM pressure varied in the AWII project from low to
moderate in most blocks to high at two of the orchards (A3 and A5). On
average, there was no real change in CM injury in either treatment
regime from 2001-2003 as measured at harvest by bin samples. The average
number of insecticide applications and the total cost of insecticides
were very similar between the two management programs. It is worth
noting that the total cost of insecticides was reduced in both
management programs each year of the project (No-OP - $250/acre in 2001,
$173/acre in 2003/acre; CONV- $220/acre in 2001, $179/acre in 2003). It
is becoming apparent after three years of the AWII that in most
situations a pheromone-based pest management program that relies on
No-OP insecticides for both CM and leafroller control with supplemental
Assail applications for CM is competitive with CONV regimes in cost and
fruit protection.

Impact Statement 

This project demonstrated that, for many orchards in Washington, apples
could be produced using a pheromone-based management approach that did
not rely on organophosphate insecticides and at no economic increase in
cost to the grower. If even half of the apple orchards in Washington
would adopt this management approach organophosphate use could be
reduced 50%. Along with federal rules that set long reentry intervals
for organophosphate insecticides new state rules on cholinesterase
testing for farm workers applying organophosphate pesticides will likely
have growers asking for pest management programs that eliminate the need
for these products. This project has helped provide a realistic basis
for alternative pest management programs that Washington growers can
adopt immediately without increasing risk of crop losses or increasing
their expenses. 

Specific Project Objectives

Compare pest control at several sites using codling moth (CM) mating
disruption as a base program supplemented with either “conventional”
insecticides or newly registered selective insecticides. 

Monitor CM and other pests using newest technology available to
supplement monitoring by crop consultants. 

Assess the impact of selected natural enemies on pests at each site
under different pest control programs. 

Evaluate the impact of different programs based on crop loss due to
pests and costs of pest controls.

Use the demonstration sites as opportunities to educate growers and crop
consultants on how different selective pest control programs work. 

Methods 

The 15 apple sites were established in Washington to compare
pheromone-based pest management programs that use conventional
insecticide treatments with those that do not use organophosphate
insecticides. Each site consists of a grower and crop consultants
willing to participate in the project. The entire site was treated with
CM mating disruption. Within each site, supplements to CM mating
disruption were either conventional insecticides (OP supplements or
other non-selective insecticides) or selective insecticides (non-OP
supplements, e.g., oil, Intrepid, Esteem). Controls for other pests
followed a “traditional conventional” or “selective
alternatives” approach. Close adherence to control programs was
expected unless crop injury exceeded acceptable levels. Management of
sites was through a combination of a local on-site manager, grower
committee, extension agent and technical advice from researchers. Crop
consultants contracted to work on the project performed assigned pest
monitoring activities. Standardized recordkeeping was established for
all monitoring activities and was continued all three years. Pest
control costs were borne by the grower with the exception of certain
non-OP products that may have been donated by the registrant. 

Monitoring activities: Standardized monitoring activities developed
under CAMP were used to assess pest insects in cooperation with crop
consultants working at the sites. Pheromone trapping was used for CM and
leafroller. New monitoring systems under development for leafrollers, CM
and lacanobia fruitworm were also incorporated into the areas to obtain
data on efficiency relative to pheromone monitoring systems and
correlation with pest density and crop injury measurements. 

Assessment of biological control: Orchards at each site were monitored
to compare effects of different programs on the kinds and abundance of
natural enemies. Pest/natural enemy systems to be monitored were spider
mites/predatory mites, aphids/parasitoids-predators and
leafminer/parasitoids. 

Program evaluation: The efficacy of different control programs was
evaluated from several different perspectives. The level of pest density
in each pest control program was determined throughout the season based
on monitoring activities and compared to arrive at a relative value for
pest suppression. The level of natural enemy density was also monitored
as described above and their abundance compared in the different pest
control programs to arrive at a relative value for natural enemy
conservation. Crop losses were determined from in-field inspection of
fruit in orchards using the different pest control programs. The level
of crop loss by pest was determined for each pest control program and
compared using statistical inference across all sites. Costs were
compared for each pest control program. 

Education: The demonstration study sites were used as field locations
for tours and workshops showing growers the results of the different
pest control programs. These educational events were held in each region
where the demonstration study sites are located to provide a local value
to the experiences of growers and crop consultants participating in the
project. Workshops and demonstrations were held each year of the project
to update the industry on progress and new products being integrated
into the pest control programs. 

Results and Discussion

Codling moth: Initially a wide range of CM populations were present
within the 15 AWII apple sites. In the first generation of 2001 CM traps
(10X) averaged 4.0 (OP blocks) and 7.0 (No-OP blocks) moths/trap and
ranged from an average of 0 to 52 moths/trap for the season. Codling
moth catches were lower in the second generation in most orchards in
2001, average of 1.7 (OP blocks) and 1.5 (No-OP blocks) moths/trap.
There were no differences in the season average capture in 10X
lure-baited traps between programs, 5.6 ± 2.1 in the OP blocks and 8.5
± 4.2 in the No-OP blocks. There were no significant differences in
codling moth captures in 10X traps between the OP and No-OP treatment
blocks in 2002 or 2003 (Fig. 1), and in most all blocks trap counts
would be considered moderate to low by industry standards. 

The DA lures attract both sexes of CM. Capture of moths in the DA
lure-baited traps was low in 2001. In the first generation, captures in
the OP and No-OP blocks averaged 72% and 70% males, respectively, while
second generation males accounted for 67% and 63%, respectively. The
percentage of mated females was slightly lower in the OP compared to the
No-OP blocks for the first generation in 2001, 32% versus 50%,
respectively. The percentage of mated females increased in the second
generation to 80% and 78%, respectively. This same trend was observed in
2002, although in 2003 the percentage of females mated was lower than in
the previous two years. Average catch in DA lure-baited traps in the
first generation was slightly lower than 10X pheromone lure-baited traps
while in the second generation catch in DA lure-baited traps was
slightly higher than in the pheromone lure-baited traps. This pattern
was different in two of 15 orchards in 2003. In these unique cases CM
capture in DA traps was about 10 times higher than in the
pheromone-baited traps. However, the high level of moth capture in the
DA lure-baited traps did not translate into high levels of fruit injury.

Figure 1. Average CM/trap for the season (10X lure-baited traps).

Leafroller: A wide range of leafroller densities was detected in the
AWII blocks in 2001. The range of moth capture per block was from 0 to
895 (OP mean 233±68 and No-OP mean 149±62) for OBLR and 0 to 554 (OP
mean 68±40 and No-OP mean 65±31) for PLR. In 2002, the average OBLR
moth captures were about the same as 2001 (OP mean 250±75 and No-OP
mean 167±61), while the PLR moth captures increased slightly (OP mean
139±49 and No-OP mean 160±50). In 2003, average OBLR moth captures
were lower than in 2001 or 2002 (OP mean 75±22 and No-OP mean 121±37),
and the PLR moth captures also decreased slightly compared to 2002 (OP
mean 94±37 and No-OP mean 124±66).

Leafroller pressure in each block was categorized using moth capture in
a standard lure-baited trap as High: >200 moths, Moderate: 100-200
moths, Low: 50-99 moths, and Very low: <50 moths per trap. The ratio of
captures in the standard and low-load lure-baited trap in each block was
used to determine if a leafroller population was internal (0 to 5),
unclear (5 to 10) or external (>10). Using these criteria, OBLR
populations were rated as being “high” in 6 OP blocks (3 with an
internal population source) and 4 No-OP blocks (only one with an
internal population source) in 2001, while PLR populations were rated as
being “high” in only 2 blocks in both OP and No-OP blocks. In 2002,
OBLR populations were rated as being “high” in 6 OP blocks (all of
which had an internal population source) and 5 No-OP blocks (with 4
having an internal population source) while PLR populations were rated
as being “high” in 5 OP and 6 No-OP blocks (all of which were rated
as having an internal population source). Most of the orchards with high
OBLR populations were in the Columbia Basin, Quincy and Brewster areas.
Orchards with high PLR populations were in the Wenatchee or Yakima
valley area. In 2003, OBLR populations were rated as being “high” in
6 OP blocks (4 of which had an internal population source) and 3 No-OP
blocks (with 2 having an internal population source) while PLR
populations were rated as being “high” in 4 OP and 2 No-OP blocks
(with none being rated as having an internal population source). The
perception that OBLR was becoming more common in all orchards over time
was not as well supported by moth capture data as by the identification
of larvae found at each location. The trend across the fruit industry is
for an increase in the densities of OBLR in apple orchards while PLR
densities have declined. This does not seem to be due to any specific
pesticide program, conventional or soft, but could be due to OBLR being
more fit (resistant) to all pesticides used in apple orchards and
because they have a higher biological potential for increase and more
alternate hosts than PLR. 

Lacanobia fruitworm: This relatively new pest was monitored with a
pheromone lure-baited trap, one per block. There was a wide range of
total moths captured but there were little differences between OP and
No-OP treatment blocks in any year. One problem with attempting to
compare lacanobia populations with pheromone traps is the strong flying
capability of these moths and their ability to move long distances. It
is probably better to rely upon other measures, such as foliage feeding
or fruit injury, to gauge the effect of different programs on this pest.

Field damage surveys

The AWII apple orchards were surveyed for damage by lepidopteran pests
four times during the growing season: late May (leafroller feeding on
shoots), early July (codling moth damage to fruit and lacanobia/cutworm
feeding on shoots), early August (leafroller feeding on shoots), and
late August/September (codling moth damage to fruit). The surveys showed
a range of pest injury among the AWII orchards. 

Codling moth (CM) surveys revealed very low levels of fruit damage in
July in all years. The preharvest surveys typically showed slightly more
CM damage than harvest bin samples. The preharvest on-tree fruit injury
surveys were also of value because they provided a better idea of injury
distribution in the orchard than bin samples. In most blocks where CM
damage was found it was largely confined to orchard edges in both OP and
No-OP blocks. There were no significant differences in average CM
damaged fruit between treatments in any year with either assessment
method (Fig. 2). 

Leafroller feeding on fruit was detected in 17, 13, and 16 of the 30
treatment-blocks in 2001, 2002 and 2003 respectively. Fruit injury by
leafrollers was higher in the OP and No-OP blocks in 2001, but there
were no significant differences between treatments thereafter. 

Fruit feeding by cutworms on fruit was detected in 15, 8, and 10 of the
30 treatment-blocks in 2001, 2002 and 2003, respectively. There was no
difference in damage levels between treatments in any year.

Figure 2.	The average percentage of fruit injury from CM in OP or No-OP
blocks over three years as measured by in-tree assessments or bin
samples. 

Damage by other pests was sporadic and rare. Stink bug damage was a
problem in some blocks in some years but was not a widespread problem
throughout the AWII blocks. Likewise, lygus damage was reported from a
few blocks each year but the levels were always low. Damage by
campylomma was reported from only two blocks (at 0.04% in each). No San
Jose scale was found in any of the 30 treatment-blocks surveyed during
the three years. Thrips damage was found in only one orchard of Granny
Smith (0.2% fruit with marking in the OP block, 0.3% in the No-OP). One
orchard of Golden Delicious had grape mealybug infesting the fruit at
harvest (1.4% infested fruit in the OP block, 0.8% in the No-OP). Fruit
damage levels in 2002 were quite low and similar to the levels found in
2001.

Pesticide use

All AWII apple blocks used CM mating disruption, most at rates close to
200 dispensers/acre, or about half the recommended full rate of the
dispensers used. CM mating disruption is included as a single
insecticide application based on the rate used (400 dispensers per acre
= 1 full application and 200 dispenser per acre = 0.5 of an
application), with cost based on the number of dispensers per acre. The
data presented here include only insecticides and miticides, not
fungicides, plant growth regulators or other non-insecticidal products.
For example, carbaryl (Sevin) used for crop load management and Lime
Sulfur or Rally used for disease suppression are not included in the
data. The main organophosphate (OP) insecticides used in the OP
treatment blocks were chlorpyrifos (Lorsban) [7 of 15 blocks] and
azinphosmethyl (Guthion) [7 blocks]. For the control of lepidopteran
pests the No-OP blocks relied upon methoxyfenozide (Intrepid) [9 of 15
blocks] and pyriproxifen (Esteem) [9 blocks]. The use of the more
selective “soft” insecticides was not limited just to the No-OP
blocks; 2 OP blocks received methoxyfenozide and 2 OP blocks received
pyriproxifen, generally applied soon after bloom for leafroller control.
Spinosad (Success) was used mostly in the OP blocks for leafroller
control (8 OP blocks, one No-OP block). Chloronicotinyl insecticides
were used in both treatment blocks but to a greater extent in the OP
blocks: imidacloprid (Provado) in 2 OP and 1 No-OP blocks, thiamethoxam
(Actara) in 1 OP and one No-OP block, and acetamiprid (Assail) in 6 OP
and 3 No-OP blocks. Miticides were used in the OP blocks (3) but not in
any of the No-OP blocks. 

The total number of insecticide applications was not significantly
different between the OP and No-OP programs in all project years (Table
1). The number of insecticides that were applied that controlled both CM
and LR were higher in the No-OP blocks in all years and were 0.5 more
over the duration of the project (Table 1). By contrast, more of the LR
specific insecticides were applied to the OP program blocks than No-OP
blocks. There were no differences in the total number of “other’
insecticides applied (mostly aphicides or controls for true bugs) in the
OP and No-OP blocks. Very few miticides were applied to any block but
there were slightly more in the OP blocks than No-OP blocks. 

Table 1.	Average number of foliar insecticides applied per acre
equivalent to AWII apple orchards, 2001-2003. 

	CM+LR	Leafroller	Mites	Other	Total

Year	OP	No-OP	OP	No-OP	OP	No-OP	OP	No-OP	OP	No-OP

2001	1.9	2.4	1.3	0.6	0.1	0.1	1.8	2.4	5.0	5.5

2002	1.7	2.0	1.2	0.2	0.0	0.0	2.1	2.1	5.1	4.3

2003	2.2	2.7	1.1	0.1	0.2	0.0	2.1	1.6	5.6	4.3

3-year avg.	1.9	2.4	1.2	0.3	0.1	0.0	2.0	2.0	5.2	4.7

To compare the relative expense of the OP and No-OP programs only
insecticide data are used. These data do not include Sevin (carbaryl),
as its main use is as to modify crop load. It no doubt has some impact
as an insecticide but its impact is not thought to be an over-riding
influence. In 2001 the cost of the OP program was $30 higher than the
No-OP program though there was no statistical difference between them
(Table 2). In 2002 the average cost of the No-OP program declined by $50
per acre and was lower than the OP program, but again the difference was
not statistically significant. In 2003 the cost of both programs
increased but was essentially the same for both programs. Oil was used
about equally by both the OP and No-OP programs. Guthion
(azinphosmethyl) was the most commonly used insecticide, other than oil,
in the OP blocks. In orchards that used Guthion, it t was used an
average of almost 2 times per acre at a cost of nearly $25. Intrepid
(methoxyfenozide) was the most commonly used insecticide in the No-OP
blocks. In orchards that used Intrepid, it was used an average of 2
times per acre at a cost of $50. The average cost of pheromone
treatments in both OP and No-OP blocks was $60 per acre. 

Table 2.	Average cost of foliar insecticides applied per acre to AWII
apple orchards, 2001-2003. 

Program	2001	2002	2003

OP	151±14.4	150±12.5	175±16.0

No-OP	183±23.7	138±14.1	170±11.8

In 2001 and 2002 the average number of Sevin applications was between
1.5 and 1.7 per block in 9 to 12 of the 15 orchards with essentially no
differences between programs. In 2003 the average use of Sevin was
lower, 1.2 times in 8 of 15 orchards. The average cost of Sevin
treatments was between $10 and $15 per acre across the project with no
differences between OP and No-OP blocks. 

Secondary pests and natural enemies

Personnel from the WSU-TFREC visited each orchard several times
throughout the season to sample specifically for a number of secondary
pests and natural enemies. These samples included campylomma, aphids,
white apple leafhopper, leafminer and spider mites. Associated natural
enemies were also sampled. There were no differences between treatments
over the three years of the study. 

 

High pressure sites – W7 and W3

Moderate pressure sites – W2 and W5 

Low pressure sites – W4 and W9 

.