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Court nixes use of dicamba on crops, again

EPA’s 2020 approval of the herbicide violated US pesticide law, federal judge rules

by Britt E. Erickson
February 7, 2024

Soybeans with cupped and blistered leaves damaged by the herbicide dicamba.
Credit: Shutterstock
Dicamba causes cup-shaped leaves and blisters on soybeans that are not genetically modified to resist the herbicide.

In a win for environmental groups, a federal court has overturned the US Environmental Protection Agency’s approval of the herbicide dicamba for use on genetically modified soybeans and cotton. The agency failed to provide notice and any opportunity for stakeholders to comment when it registered three dicamba products in 2020, the court ruled Feb. 6.

The products in question, made by Bayer, BASF, and Syngenta, are prone to volatilization under high temperatures and temperature inversions. Under such conditions, the herbicide can drift off-site and wreak havoc on plants in its path.

Chemical structure of dicamba.

Dicamba has been used for decades to control weeds in late winter or early spring, before crops are planted. But use of the herbicide in the US increased dramatically in 2017 after the EPA allowed farmers to spray it directly on genetically modified soybeans and cotton. Over the next 2 years, states received thousands of complaints about damage to off-site plants, including to soybeans that were not modified to tolerate the herbicide. Environmental groups sued the agency for not considering risks to nontarget plants and endangered species.

The groups won the case in early 2020, when a federal appeals court overturned the EPA’s approval of the three dicamba products used on soybeans and cotton. But 4 months later, the agency registered the three products again. Environmental groups again challenged the approvals in court, and the latest ruling cancels the registrations.

Groups that filed the suit are calling the court’s decision a victory for family farms and endangered species. “I hope the court’s emphatic rejection of the EPA’s reckless approval of dicamba will spur the agency to finally stop ignoring the far-reaching harm caused by this dangerous pesticide,” Nathan Donley, environmental health science director at the Center for Biological Diversity, says in a statement. “Endangered butterflies and bee populations will keep tanking if the EPA keeps twisting itself into a pretzel to approve this product just to appease the pesticide industry.”

Agrochemical companies are assessing their next steps. “We respectfully disagree with the ruling against the EPA’s registration decision,” Bayer says in an emailed statement. “We also await direction from the EPA on important actions it may take in response to the ruling,” the company adds. “Our top priority is making sure growers have the approved products and support they need to safely and successfully grow their crops.”



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