Aug 30, 2005

EPA Pulls Plug on Some Guthion Uses

The Environmental Protection Agency has decided to end the use of azinphos-methyl (Guthion, Azinphos-methyl 50WS) on peaches, nectarines, caneberries, cranberries, potatoes, cotton and Southern pine seed.

EPA ruled that existing supplies of the insecticide can be used on these crops through Sept. 30, 2006.

When EPA proposed terminating these so-called “group 2” azinphos-methyl uses, several producer groups asked for an extension. EPA accepted comments this spring, but in its August ruling said it found insufficient reason to justify extending the uses.

Growers with current labeled product can use azinphos-methyl only through next growing season.

The ruling appears in the Aug. 17 Federal Register, at www.epa.gov/fedrgstr, with a crop-by-crop explanation of why extended use was not granted. For every crop, EPA listed pesticides that it says give effective pest control with less hazard to people and the environment.

Some Background

EPA issued the Interim Reregistration Eligibility Decision (IRED) for azinphos-methyl in October 2001. In May 2002, the technical registrants (Bayer CropScience, Gowan and Makhteshim Chemical Works) agreed to implement the provisions of the IRED by dividing the universe of azinphos-methyl uses into three groups. Group 1 contained 23 crops with little use that were deleted from product labels immediately.

Group 2 consisted of seven uses that were originally scheduled to be phased out in December 2005. It is within this group that uses have now been banned.

Group 3 is comprised of 10 uses that have time-limited registrations pending submission and evaluation of biomonitoring, product efficacy and other data.

For the azinphos-methyl Group 2 crops, EPA received comments and requests to extend some uses, and replied to them in the following manner:

Caneberries

For caneberries, the Oregon Raspberry and Blackberry Commission and the Ohio Farm Bureau requested that EPA eliminate or extend the phase-out. The request was based on the need to control raspberry crown borer in blackberries and raspberries. Currently, diazinon is the only alternative and concern was expressed that resistance to diazinon may occur. The comments also said that diazinon application is only allowed once per growing season, so if azinphos-methyl is removed, growers who face both the raspberry crown borer and the raspberry fruitworm (another sporadic pest) may need to dedicate the single application of diazinon to fruitworm control, leaving no alternative for the crown borer.

EPA replied that resistance is unlikely, since the diazinon applications are only made every other year. Moreover, carbaryl and spinosad are both labeled for use against the fruitworm, and the presence of these alternatives should allow growers to use diazinon in place of azinphos-methyl for crown borer control. EPA found insufficient justification for extending azinphos-methyl use on caneberries.

Cranberries

The Cranberry Institute requested an extension of the phase-out of azinphos-methyl use on cranberries in Wisconsin for two to three years, based on the need to control cranberry fruitworm.

The agency concluded that there are several other active ingredients, including acephate, carbaryl, chlorpyrifos, diazinon, phosmet, methoxyfenozide and tebufenozide, registered to control the cranberry fruitworm.

Peaches

For peaches, the Northwest Horticultural Council and researchers from the University of Georgia and Rutgers University requested EPA eliminate the phase-out of azinphos-methyl use on peaches, based on the need to control the peach twig borer in the Northwest, lesser peach tree borer (LPTB) in the Southeast, and the oriental fruit moth and San Jose scale in the Northeast.

The LPTB has emerged as a pest since phosmet replaced methyl parathion in the treatment regimen, they said.

The EPA replied that the other pests listed were evaluated in 2001 and are insects with longstanding pest status. Therefore, EPA said it focused on the LPTB in assessing the need for continued use of azinphos-methyl on peaches.

The LPTB is an insect that at one time was only seen in older or diseased trees. This pest has begun attacking productive limbs of younger trees during the growing season as well as overwintering under tree bark. The increased infestation of the LPTB is a newly emerging problem, EPA said, which makes it difficult for crop experts to accurately determine the extent of the southeastern peach acreage that is affected. It is also not clear whether azinphos-methyl is the only effective option to control these infestations. EPA acknowledged the potential for loss due to the LPTB, but said it had no evidence to confirm that azinphos-methyl is the best choice for control. Therefore, the agency found insufficient justification for extending azinphos-methyl use on peaches and nectarines.

Read the full notice on the Federal Register at http://frwebgate4.access.gpo.gov/cgi-bin/waisgate.cgi?WAISdocID=4156892323+0+0+0&WAISaction=retrieve.