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Ag groups challenge EPA's withdraw of herbicide approval

Already-exhaustive review undertaken by both USDA and EPA on the Enlist family of products draws concerns into EPA's actions.

In a letter to Environmental Protection Agency Administrator Gina McCarthy, a coalition of major farm groups pressed the agency to withdraw its request to vacate the registration for Dow’s Enlist Duo herbicide, highlighting the urgent need for new modes of action to tackle resistant weeds on farms across the country.

Ahead of Thanksgiving, EPA withdrew its approval of the weed killer which combines glyphosate and 2-4D to deal with growing resistance issues. Following the approval in October 2014, several environmental groups sued EPA in the Ninth Circuit Court of Appeals on EPA’s decision to register the Enlist Duo pesticide product for use on corn and soybean genetically modified to be tolerant of this pesticide. 

On Nov. 25, EPA asked the court to vacate and remand the registration of the pesticide Enlist Duo “because the agency has received new information from Dow AgroSciences – the registrant of Enlist Duo – that suggests two active ingredients could result in greater toxicity to non-target plants. Dow had not provided this information to EPA prior to EPA issuing the Enlist Duo registration. EPA has not yet completed its review of the new information,” EPA said in a statement.

“U.S. growers have an urgent need for a new mode of action as these regulatory delays have exacerbated the proliferation of hard-to-control weed populations. These delays are necessitating more intense weed control practices that complicate environmental management,” wrote the groups in the letter. “Herbicide tolerant cropping systems allow growers to more efficiently use active ingredients for weed control while providing environmental benefits like reduced tillage that improves soil heath and limits nutrient run-off. Additional herbicide modes of action will help proactively manage weed herbicide resistance.”

The groups cited the already-exhaustive review undertaken by both USDA and EPA on the Enlist family of products.

“Among the many new requirements for registration of Enlist Duo at EPA was an unprecedented review of the potential effects of the product on threatened and endangered species. After an exhaustive state-by-state review, EPA concluded that use of Enlist Duo in accordance with the product label, which imposed a 30-foot wind directional buffer zone, would have no effect on threatened and endangered species. This review took place on a product that simply combines two herbicides that have each been on the market for decades…” wrote the groups.

The groups also took issue with EPA’s reference to additional and new data in its decision to reevaluate Enlist Duo.

“There will always be new information to be considered about products EPA has registered. Congress has recognized this, and included in FIFRA several vehicles for reviewing products. But none of these vehicles authorize the agency to withdraw a previously approved product in the absence of an ‘imminent hazard,’” wrote the groups. “… No one has suggested that the information EPA now is considering with Enlist Duo comes close to meeting that threshold."

Those who signed the letter include the American Soybean Assn., American Farm Bureau Federation, National Corn Growers Assn., National Cotton Council and the National Farmers Union.

Tim Hassinger, Dow AgroSciences president and chief executive officer, said it’s possible that there could be some changes to use conditions on the existing Enlist Duo label. “We believe the questions that have been raised about any potential synergy between 2,4-D choline and glyphosate can be promptly resolved in the next few  months, in time for the 2016 crop use season,” he said.

Hassinger added, “However, based on the ongoing dialogue with EPA, we do not expect these issues to result in the long-term cancellation of the Enlist Duo product registration. We continue to prepare for commercial sales of Enlist Duo for the 2016 growing season, with enthusiastic grower adoption.”

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