Cotton farmers battling glyphosate resistant weeds may take another shot, if the Environmental Protection Agency (EPA) follows through on plans to ban arsenic-containing herbicides. DSMA and MSMA, both popular pre-Roundup Ready herbicides are among the products on the chopping block.

In the Aug. 9, 2006 Federal Register (Volume 71, Number 153), the agency stated: This notice announces the availability of EPA's Reregistration Eligibility Decision (RED) for the organic arsenical herbicides MSMA, DSMA, CAMA, and cacodylic acid, and opens a public comment period on this document. The Agency has determined that all products containing MSMA, DSMA, CAMA, and cacodylic acid are not eligible for re-registration.

MSMA and DSMA, prior to Roundup Ready technology, were used for a wide spectrum of weed and grass control. These materials are especially effective against cocklebur, lambsquarter and other small-seeded weeds, plus nutsedge and annual grasses in cotton.

Though not officially documented, researchers are fairly sure they have isolated glyphosate resistant lambsquarters. If this resistance is documented and proves to be widespread, arsenic-based herbicides would be the least cost, most effective management tools available to farmers.

“We used a lot of MSMA and DSMA before we had Roundup Ready cotton,” notes Virginia cotton grower Dean Stallings. Stallings and fellow Smithfield, Va., farmer Robbie Taylor say these materials have not been widely used in their area in recent years because of the effectiveness of glyphosate-based herbicides in controlling these pests.

“If we lose MSMA and DSMA, and if lambsquarters is resistant to glyphosate, it would be an economic loss for us,” Taylor says.

Farmers, turf managers and others concerned about the loss of arsenic-based herbicides can send their comments to the EPA by Oct. 10, 2006. Comments must be identified by docket identification (ID) number EPA-HQ-OPP-2006-0201, by one of the following methods:

• E-mail to http://www.regulations.gov/ and follow on-line instructions.

• Mail to: Office of Pesticide Programs, Regulatory Public Document (7502P), Environmental Protection Agency, 1200 Pennsylvania Avenue, NW, Washington D.C. 20460-0001

• Deliver to the EPA, Room S-4400, One Potomac Yard (South Building) 2777 South Crystal Drive, Arlington, Va.

e-mail: rroberson@farmpress.com