EPA explains cotton herbicide registration delays

It is not clear when the new auxin-based herbicide formulations for the Xtend or Enlist seed traits will be available for cotton growers.

Speaking to growers at the 2016 Southeast Fruit and Vegetable Conference in Savannah, Ga., Jan. 8, Rick Keigwin, deputy director for EPA Office of Pesticide Programs, said the agency is considering newly available studies before making a registration decision.

Background: On Nov. 25, the EPA asked the Ninth US Circuit Court of Appeals to vacate the agency’s registration of the Enlist Duo herbicide, a decision spurred mostly by a lawsuit against the agency filed in California by coalition of conservation groups.

Enlist Duo is a premix product which combines a new 2,4-D formulation (2,4-D choline) and glyphosate. Once it is registered by EPA, farmers can apply it over the top of approved Enlist crops.

“In the course of those legal proceeding, we (EPA) become aware of new data that the registrant had submitted to another government agency to support a patent, and that patent showed synergy between 2,4-D and glyphosate,” Keigwin said, who added the registrant did not provide EPA with that data, which could be important  in determining what the buffers are for the product.

The synergy between 2,4-D and glyphosate means the two products together work differently than the two products independently and that synergy can also influence recommended rates for the product.

Roundup Xtend herbicide, which is a premix formula of glyphosate and dicamba, is not yet registered for use in cotton in 2016. In addition to this premix, BASF and Monsanto are seeking registration for formulations containing the active ingredient of just dicamba, which will be Engenia and XtendiMax. Although there are no current premixes of glufosinate (Liberty) with dicamba or 2,4-D formulations, both cotton seed trait technologies will have tolerance to topical applications of glufosinate.  Growers need to keep in mind this is not the case for Xtend technology in soybean, which will not be tolerant to glufosinate.

Timeline hard to predict

Keigwin said he and the EPA understand the intense interest the U.S. farming industry has for the two new cropping systems, which many in the industry feel necessary for farmers to control what are increasingly becoming hard-to-manage weeds.

“I can say that very, very recently we received data … that we did not have. So those data need to be evaluated before we can provide a registration timeline. We have made a commitment, particularly for the herbicide tolerant crop registrations, to have (public) comment periods,” said Keigwin, who added the broader public interest is to make sure the registrations decisions are scientifically supportable and legally defensible.

Speaking again about the Enlist Duo patent, Keigwin said:

“Turns out there were well over 100 studies the registrant submitted to support that patent. So, we are in the process of going through all of those studies right now. I wish I could tell you how long it will take. But those types of studies, we have never seen before. So, trying to figure out how to review them and then how to incorporate them into a regulatory decision is a little bit something new for us,” said Keigwin.

Tommy Gray, head of the Georgia Department of Agriculture Plant Industry Division, told the growers at the Savannah meeting regardless of when the new auxin-based herbicides get registered, the Georgia Department of Agriculture, in partnership with University of Georgia Extension, will move forward with mandatory training for the new auxin herbicide formulations, trainings required to legally apply these new auxin herbicides in-season for the cotton and soybean trait technologies in Georgia. The trainings help growers make wiser decisions when applying pesticides, which protects them, their neighbors and the environment.

Georgia growers who attended a similar training in 2015, as long as they registered at the meeting, are not required to attend the meeting again, but they are welcome to attend as many times as they like.

Last year, 1,061 Georgia growers completed the training for the new auxin technology. According to a UGA Extension survey conducted at the training, 99 percent of these growers felt the training was worth their time and 98 percent of them felt the training would help them increase on-target pesticide applications.

The times and locations of the 2016 trainings will be available later this winter.

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