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Will dicamba be usable in 2025?

The 2024 Arizona decision focused on procedural issues linked to how the EPA reviewed labels for registration in 2020, rather than the herbicide itself.

Mary Hightower

May 28, 2024

4 Min Read
Dicamba Damage Soybeans
These soybean plants show signs of dicamba injury, indicated by necrosis on the leaf tip causes constriction, which makes the leaf cup upwards. The leaf surface may also show signs of blistering or puckering.Bob Scott

At a Glance

  • Endangered Species Act likely to figure in dicamba’s future
  • Arizona court ruling focused on procedural issues

Time is not on dicamba’s side.

Following an Arizona federal court ruling that vacated the label in February, users of dicamba herbicides are waiting to see what happens now that a new registration for over-the-top use of XtendiMax during the 2025 season has been submitted to the Environmental Protection Agency.

Herbicides containing dicamba have been widely used by cotton and soybean growers to combat weeds that have developed resistance to other chemical controls. The EPA regulates herbicides and must approve the labels, which include directions for use and precautions.

Three dicamba brands are registered for use by the EPA: XtendiMax, Engenia and Tavium.

The proposed new label for XtendiMax includes a significant change — not allowing for over-the-top use on soybeans,” said Brigit Rollins, staff attorney for the National Agricultural Law Center.

New use, food use

The XtendiMax submission also included a new twist: an R170 registration for food use. According to the EPA, R170 would include “uses on areas where food may be grown or raised such as pasture, rangeland, home garden, beehive, and uses involving livestock, such as livestock housing, livestock dips, and livestock ear tags.”

Dicamba formulations have been commonly used to manage weeds in pastures.

Related:Farmers have herbicide options despite dicamba ruling

Why the R170?

“The court said that the manufacturer needed to pursue a new-use registration,” Rollins said. “Bayer probably saw the R170 additional food use as the best fit as a new-use registration, but they might have a completely different reason.”

However, the review timeline may be longer than the growing season, Rollins said.

“The public comment period that’s currently open on this label is for 30 days, but there is a good chance that it will be extended,” she said. “Various environmental groups have indicated that they would like to push for at least a 60-day comment period.”

The current comment period opened May 2 and ends June 3. EPA also has a 15-month review just for the R170.

“With the extended comment period and EPA’s 15-month decision time for the R170 label, “that’s a review period of 17 months,” Rollins said. “It’s hard to see how this label would be approved before the 2025 growing season. The label could be approved as early as fall 2025, if we’re doing our math correctly.”

Rollins did say that the EPA could choose to modify and shorten the review period, but any follow-up lawsuits would again target the procedures “because that worked so well last time.”

The Arizona court order allows for existing stocks of XtendiMax, Tavium and Engenia to be used in 2024 and defines those stocks as being previously registered pesticide products that are currently in the United States and were packaged, labeled and released for shipment prior to Feb. 6, 2024, the date of its order. The products must be used according to the label.

Related:Weeds: Get ‘em while you can

Scuttled by procedural issues

Dicamba has been registered for use in the U.S. since 1967 and controversial for its tendency to move, or drift, from its target application area. Newer formulations using dicamba were approved by the EPA in 2016.

The 2024 Arizona decision focused on procedural issues linked to how the EPA reviewed labels for registration in 2020, rather than the herbicide itself. This strategy was first employed in 2016, with one of the first lawsuits over the herbicides.

At the heart of the 2016 lawsuit, and subsequent lawsuits, are the Endangered Species Act and FIFRA, or the Federal Insecticide, Fungicide, and Rodenticide Act, which regulates pesticide use in the U.S. The Endangered Species Act requires all federal agencies to ensure their actions will not jeopardize endangered or threatened species. Under the Endangered Species Act, the EPA must consult the U.S. Fish and Wildlife Service and the Marine Fisheries Service when approving pesticides.

However, the herbicides’ labels for use expired before the courts could take up the 2016 case. The herbicide makers filed for an expanded label, which was granted in 2018.

Twice vacated

Plaintiffs refiled their lawsuit in 2018 and a 2020 decision by the 9th U.S. Circuit Court of Appeals  stated, “that the 2018 pesticide registrations violated FIFRA because EPA had wrongly concluded that the label amendments right that this sort of registration of over-the-top use would not significantly increase the risk of unreasonable adverse effects on the environment,” Rollins said.

“Specifically, the 9th Circuit called out EPA for substantially understating three risks that EPA had identified when it analyzed the label, and also that EPA had failed to acknowledge three other risks in its analysis,” she said.

The labels were vacated in 2020 and manufacturers sought new registrations to allow over-the-top use of the dicamba herbicides from 2021-25. This multi-year registration was the subject of the Arizona court decision this year.

In both rulings vacating the registrations, the court allowed farmers to use existing stocks.

As for the future, Rollins said litigation over dicamba herbicides centered around FIFRA and the Endangered Species Act are not likely to go away anytime soon.

For a deeper dive, see Rollins’ webinar, “What’s the Deal with Dicamba?”

Mention of product names does not imply endorsement by the University of Arkansas System Division of Agriculture.

Source: University of Arkansas System Division of Agriculture

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