Information Requests Monitoring System

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Request ID: 149
Request From: Steve Toth
Date Requested: Mar 10, 2006
Request: Note the following request for information on the use of malathion on walnuts, almonds and pecans. Please circulate among the experts in your state/territory and send their responses to the Southern Region IPM Center Information Responses Monitoring System within the next week. Thanks. Steve Toth -------------------------------------------------- To reduce calculated drinking water risk estimates, EPA is reviewing the use of malathion on walnuts. The current maximum Cheminova-supported rate is 2.5 lb a.i./A x 3 applications x 7 day retreatment interval. However, EPA believes the typical application rate is 3.8 lb ai/A x 1 application up to 6 lb a.i./A x 1 application. Applications have been made as high as 8 lb ai/A. EPA has asked growers to consider as a risk mitigation measure: that all future labels will have a new maximum of 2.5 lb ai/A x 3 applications x 7 day retreatment interval. The residue data for walnuts is supportive of malathion use on pecans and almonds. Could pecan and walnut growers also comment on if they can accept the EPA-proposed new maximum? IF not, what maximum label rate is needed and why? If EPA's new maximum application rate is a problem for walnut, almond and pecan growers, we will need to see if another registrant or IR-4 will undertake residue studies to support higher application rates of 3.8 lb ai/A to 8 lb ai/A. We would also see if any further refinements can be made to the EPA drinking water risk assessment. Please let me know your thoughts in two weeks. EPA is slowly working its way through a list of 20 crops with the highest usage of malathion. Then we go onto Group 2 and Group 3. Thanks again for your assistance: Please do not hesitate to contact me if you have any questions or comments. Teung F. Chin, Ph.D. Biological Scientist Office of Pest Management Policy Agricultural Research Service United States Department of Agriculture LOCATED AT: USDA Animal & Plant Health Inspection Service 4700 River Road, Unit 149 (Room 3D-06.8) Riverdale, MD 20737-1237 Phone (301) 734-8943 Fax (301) 734-5992 Teung.F.Chin@usda.gov http://www.ars.usda.gov/opmp

Responses
Responder: Charles Luper
State: OK
Date Requested: Mar 10, 2006
Response: According to Dr. Phil Mulder these rates would be OK for Oklahoma pecans. Malathion is not heavily used on commerical pecans.

Responder: Mike Weaver
State: VA
Date Requested: Mar 10, 2006
Not Important/Relevant to my state(s)
Response: Steve: Virginia does not have commercial acreage of pecans, walnuts or almonds. There could be a few individuals who grow pecans or walnuts, but not for sale to my knowledge. So the issue does not affect us. Thanks and take care, Mike Weaver SR-IPM Center State Contact - Virginia

Responder: Darrell Hensley
State: KY
Date Requested: Mar 10, 2006
Response: Ric Bessin indicated Kentucky is not growing these crops commercially. D.Hensley

Responder: Marvin Harris
State: TX
Date Requested: Mar 12, 2006
Response: Our (Bill Ree & I, 2003 season)latest producer survey records indicate malathion usage constitutes 21% of insecticide sprays applied to pecans in Texas. We are currently seeking clarification from producers regarding rates, but surmise that 2.5 lbs ai per acre per treatment is a sufficient maximum under most conditions. The proposed limitation to 3 malathion treatments per season will not usually be a problem because the average total number of insecticide treatments per season is <4, however there may be a few growers that are affected and one can envision a periodic insect problem that may require more than 3 treatments every couple of decades or so. The proposed reentry interval extension from 12 hrs to 7 days can potentially cause a major problem in the conduct of routine orchard operations like weed control, fertilization, pruning, thinning, irrigation, etc., given that producers have become accustomed to conducting these operations using a much shorter reentry interval. I would note that malathion usage significantly increased following the loss of phosalone over a decade ago and that producers using malathion do so in lieu of chlorpyriphos (or less commonly, tebufenozide)under most circumstances. Bill Ree, Doug Stevenson and others may also wish to comment on this.

Responder: Mark Mossler
State: PR
Date Requested: Mar 14, 2006
Not Important/Relevant to my state(s)
Response:

Responder: Mark Mossler
State: VI
Date Requested: Mar 14, 2006
Not Important/Relevant to my state(s)
Response:

Responder: Mark Mossler
State: FL
Date Requested: Mar 14, 2006
Response: Based on profiles, this modification does not appear to impact pecan growers. However, is there a chance of just having a 7.5 lb ai/A maximum seasonal use so if a grower just wanted to make one application near the assumed maximum (8 lb ai/A), they could do so?

Responder: Ples Spradley
State: AR
Date Requested: Mar 14, 2006
Response: Below is the response from Mr. Arthur Davis, President of the recently formed Arkansas Pecan Growers Association. Mr. Davis also is a member of the Arkansas State Horticulture Society. The only thing that I would consider using malathion for is for phylloxera at 1.2 pint to a 100 gallons so it will not damage the ladybugs. You can also use it for black and yellow aphids but if you have lots of ladybugs you will not have to spray. You can also use lorsban for plylloxera. I do not spray the trees for any thing unless we have pecan weevils. You will also take care of the shuckworn when you spray.

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