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Court cancels dicamba herbicide registration

Ruling nixes the use of herbicides formulated to spray on popular genetically modified soybean varieties

by Melody M. Bomgardner
June 4, 2020

This image shows cupped soybean leaves, a sign of dicamba damage.
Credit: Mark Loux/Ohio State University Extension
Soybeans growing in Ohio show leaf cupping, a sign of damage from dicamba.

A June 3 ruling by the US Court of Appeals for the Ninth Circuit vacates a US registration allowing farmers to spray dicamba-tolerant soybeans and cotton with three versions of the herbicide. The herbicides, sold by BASF, Bayer CropScience, and Corteva, were first registered for the 2017 growing season for use on soybeans developed by Monsanto, now owned by Bayer.

A coalition of health and safety advocacy groups sued to overturn that first registration; the suit was refiled when the US Environmental Protection Agency renewed it in 2018. The coalition said the EPA’s decision violated the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Endangered Species Act.

In 2017, the first year farmers could use dicamba products during the growing season, the herbicide damaged an estimated 3.6 million acres of non-tolerant soybeans when it drifted from fields where it was applied. The damage persisted in 2018, a year when more than half of US soybeans were planted with the tolerant variety, the court found.

At the time, BASF, Bayer, and DuPont (now Corteva) said their dicamba formulations would not drift. The Bayer and DuPont products contained a diglycolamine salt of dicamba and a proprietary additive, VaporGrip, to reduce volatility. BASF developed an N,N bis(3-aminopropyl)methylamine salt of dicamba to prevent movement.

But thousands of reports of herbicide damage to non-target soybeans and other crops caused the EPA and some state agriculture departments to tightly restrict the use of dicamba in the growing season. Farmers and weed scientists complained that it was close to impossible for growers to apply the herbicide while following the rules.

The Court determined that the EPA’s registration of the herbicides violated FIFRA. It held that the EPA understated how much dicamba would be used by farmers and did not properly acknowledge “substantial and undisputed” damage to other crops from the drifting chemical.

The verdict went on to say the EPA did not acknowledge the risks that the label restrictions would not be followed and that farmers were forced to purchase dicamba-tolerant varieties to avoid crop damage. “Finally,” the court said, “EPA entirely failed to acknowledge the risk that [growing season] dicamba use would tear the social fabric of farming communities,” as farmers blamed each other for damaged fields.

In a emailed statement, Bayer says: “We strongly disagree with the ruling and are assessing our next steps. We will also await direction from the EPA on actions it may take in response to the ruling.” Bayer says it is working to obtain EPA registration for the 2021 season and beyond.

Many farmers have already planted dicamba-tolerant soybeans this season and had purchased dicamba herbicides to use on them. It is not clear when or if that practice will again be legal.

“Our top priority is making sure our customers have the support they need to have a successful season,” Bayer wrote.

BASF and Bayer are appealing a February federal jury award to Bader Farms, a Missouri peach farm that alleged economic harm from dicamba drift. The jury awarded $15 million in compensatory damages and $265 million in punitive damages.


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