Comments on EPA Memorandum on 2005 Grower Impact Assessment of
azinphos-methyl use on apples (DP 307589)

Dr. Larry Gut

Michigan State University

Department of Entomology

243 Natural Science

E. Lansing, MI 48824

(517) 353-8648 

  HYPERLINK "mailto:gut@msu.edu"  gut@msu.edu 

In the absence of Guthion, avoiding unacceptably high levels of fruit
damage by Midwest apple grower's is likely to require the use of mating
disruption, insect growth regulators such as novaluron, neonicotinoids,
and other alternative chemistries. The effectiveness and economics of
pest management programs that combine these tactics has been
investigated over the past four years in a USDA funded RAMP project.
This effort provides the most direct measure of the economics of
producing apples in Michigan in the absence of azinphosmethyl.

The efficacy and economics of a reduced-risk and a standard pest
management program were directly compared on nine farms. The
reduced-risk programs combined the use of biopesticides (e.g., mating
disruption), and reduced-risk and OP-replacement pesticides. The
standard programs relied heavily on the use of azinphosmethyl, but
included phosmet, carbamate insecticides such as methomyl, and
pyrethroids such as esfenvalerate.

The extent of fruit damage sustained under the two management programs
was similar. Both provided good control of the pests that are the main
targets of azinphosmethyl, codling moth, plum curculio and apple maggot.
However, the average cost of materials required to achieve control was
quite a bit higher for the reduced-risk compared to the standard
programs (Figure 1).  The increase in costs ranged from 2-fold to
3.1-fold. This represented a substantial increase in production costs.

Combining all three years, grower expenses for insect and mite control
averaged about $425 per acre in the reduced risk programs versus $170 in
the standard programs. Under this scenario, replacing an
azinphosmethyl-based program with an equally efficacious alternative
program resulted in a $255 per acre decrease in revenue for the grower.

This economic analysis does not include the increased cost for scouting
that will be required to implement the reduced risk program. A
conservative estimate would be $50 per acre, or at least $15 more than
is required for scouting in the current standard program. Apples are
grown on approximately 43,000 acres in Michigan. Growers farming a
majority of the acreage rely on azinphosmethyl for efficacious and
economical control of the major fruit-damaging pests. At an increased
pest control cost of $270/acre, in the absence of azinphosmethyl, the
annual loss in revenue to the states apple growers could exceed $10
million.

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