US EPA revives dicamba registration

On Oct. 27, US Environmental Protection Agency Administrator Andrew Wheeler announced the EPA will approve new 5-year registrations for two dicamba herbicide products: Bayer’s XtendiMax and BASF’s Engenia. The news means farmers planting soybeans or cotton in 2021 can use the herbicides on crops engineered to tolerate dicamba, provided they follow new application directions.

In June, a ruling by the US Court of Appeals for the Ninth Circuit vacated the EPA’s 2017 registration of the products. The court found that the herbicides drifted from where they were applied and were responsible for damaging crops, including 1.5 million hectares of nontolerant soybeans in 2017. It also found that the damage—and resulting harm to farming communities—persisted in 2018.

Wheeler announced the new registration at a cotton farm in Brooklet, Georgia. At another stop in nearby Savannah, attended by state agricultural leaders and members of Congress, he said the move was an example of the EPA’s ongoing cooperation with the agricultural community.

He also touted the EPA’s earlier guidance allowing farmers to use dicamba through the end of July 2020, despite the court ruling. “EPA worked hard so farmers can use previously purchased dicamba despite a surprise court decision in June that threatened to end the planting season—and the livelihood—of many farmers,” Wheeler told attendees, according to an EPA press release.

The new registration requires farmers using XtendiMax and Engenia add a separate pH buffer to their tank mixes to reduce volatility of the products. Both products were originally formulated with low-volatility salts, which Bayer and BASF said would prevent drift, however thousands of farmers reported damage from the herbicides.

Farmers will also have to follow new label instructions that expand the size of a buffer zone where farmers can’t spray dicamba and prohibit use of the herbicide on soybeans after June 30 and on cotton after July 30.

Health and environmental advocacy groups are unconvinced that new rules will prevent dicamba drift. Bill Freese, a science policy analyst for the Center for Food Safety, tells C&EN he does not have faith the new additives will be effective. He adds that the EPA continues to rely solely on company data in determining the products’ safety.

The CSF, along with the Center for Biological Diversity, National Family Farm Coalition, and Pesticide Action Network brought the earlier lawsuit and say they will challenge the new registration in court.

In contrast, farmers beset by hard-to-kill weeds that have developed resistance to herbicides such as glyphosate, commonly known as Roundup, were cheered by the news. Cotton growers, for example, can lose 50% of their yield to competition from resistant weeds.

“The economic damage that would result from not being able to use dicamba herbicides would be tremendous,” National Cotton Council chairperson Kent Fountain says in a statement.

It is not yet clear how state departments of agriculture will respond to the EPA’s label rules for dicamba. Last year in response to widespread reports of damaged soybeans, Arkansas enacted tight controls on dicamba use, including an application cutoff date of May 25.