In light of the Environmental Protection Agency’s recently announced new policy and priorities for Endangered Species Act review of new conventional pesticide active ingredients, BASF submitted a voluntary request to cancel its Tirexor herbicide registrations on February 14, but plan to reapply in the near future. The EPA approved trifludimoxazin last year for nationwide use on corn, soy and many other fruit, nut and vegetable crops.

The Center for Food Safety and Center for Biological Diversity touted the action as a direct response to the conservation groups’ December 2021 filings seeking to have the federal court overturn EPA’s registration of the pesticide.

After the public comment period closes and the registrations are canceled by the EPA, BASF says it will apply for new Tirexor herbicide registrations. “This will allow Tirexor herbicide to be placed in the EPA priority queue for ESA review and the applications will go through the EPA's new ESA policy,” says Miracle King-Wilson, spokesperson for BASF, in an email response. “The voluntary cancellations do not reflect any concerns by BASF about the safety or efficacy of Tirexor herbicide.” 

BASF says it “remains committed to complete compliance with the law and to the health and safety of those who use and are exposed to our products. We view this process as the best way to assist EPA in meeting all legal requirements, particularly compliance with the ESA.”

In documents provided to EPA on the support of the new active ingredient trifludimoxazin, the American Soybean Association says trifludimoxazin is a Group 14, protoporphyrinogen-oxidase-inhibiting mode of action herbicide. While there are several documented weed varieties that have shown resistance to Group 14 herbicides, ASA was pleased to learn trifludimoxazin may have unique PPO-binding properties that would make it an effective management tool for weed populations that have developed resistance to other PPO-inhibiting chemistries.

“This effectiveness against other PPO-resistant weed populations, coupled with trifludimoxazin’s tank mix and rotational potential – allowing the layering of chemistries with multiple MOAs – would make this a useful chemistry for soybean growers,” their comments noted. “Of additional benefit is trifludimoxazin’s ability to control and suppress a variety of both broadleaf weeds and grass species. Some chemistries target one weed type or the other, but trifludimoxazin’s ability to control both could reduce the operational costs of growers who otherwise may need multiple chemicals to address both needs.”

Wendy Brannen, ASA spokesperson, adds that the new ingredient was not currently used on soy farmers, however it was seen as a potential solution to herbicide-resistant weeds controlling a broad spectrum of existing herbicide-resistant weed varieties, as well as protecting against the emergence of new ones.

“We are certainly disappointed with this news, as trifludimoxazin has unique properties that could have been exceptionally useful for growers in dealing with herbicide-resistant weed populations, which can better help growers protect their crops and maintain vital conservation practices, such as reduced tillage,” Brannen says. “It is disturbing that pesticide opponents are so aggressive in their efforts that it undermines the environmental sustainability of agriculture by forcing these types of outcomes, but we understand and appreciate the difficult decision the registrant has made.”

BASF says it is disappointed that availability of this valuable crop protection tool is delayed because EPA did not incorporate its ESA assessment into the initial registration process but appreciates that under EPA’s new approach the needed ESA assessment will be conducted. 

“Growers continue to need solutions and technologies to control their toughest weeds, and Tirexor herbicide will be a valuable resistance management tool used to control PPO-resistant weeds,” King-Wilson adds. “BASF believes in the value herbicides add to farming operations across the country, which is why we will continue to invest in bringing these solutions to market in accordance with EPA regulatory requirements.”

Meanwhile, the Center for Food Safety and Center for Biological Diversity claims, “The EPA’s greenlighting of use of this pesticide on millions of U.S. acres last year came despite the agency’s acknowledgment that spray drift and runoff of trifludimoxazin are likely to cause damage to wild plants and animals. The EPA’s own analysis found that the pesticide is highly toxic to aquatic and terrestrial plants, with likely drift damage to plants more than 1,000 feet from a field’s edge.”

“Trifludimoxazin should never have been approved to begin with, but we are gratified BASF has recognized our case’s merit, capitulated and will remove its product from the market without further litigation,” says George Kimbrell, CFS legal director and counsel in the case. “The EPA and the pesticide industry have suffered a string of losses in recent years, and they don’t seem to want to lose another.”