EPA Comment Period Opens on OTT Dicamba

JEFFERSON CITY, Mo. (DTN) -- After doing without in 2025, U.S. cotton and soybean growers could once again have access to dicamba herbicides labeled for postemergence application under a proposed registration released on Wednesday by EPA for public comment.

The agency's proposed registration eliminates cutoff dates and crop growth stages that were previously used to govern application of "over-the-top" (OTT) dicamba products, including BASF's Engenia, Bayer's XtendiMax and Syngenta's Tavium. Instead, mitigations to prevent drift and off-target movement include a single use maximum application rate of 0.5 pounds acid equivalent of dicamba per acre with no more than two applications allowed with a maximum annual application of 1 pound acid equivalent of dicamba.

Additional mitigations include prohibition of aerial applications, a 240-foot downwind buffer, the use of approved drift-reduction agents and pH-buffering volatility reduction agents and temperature-dependent application restrictions to manage volatility, including a prohibition on applications when the temperature is above 95 degrees Fahrenheit.

In a memorandum supporting the proposed decision, EPA wrote that "the proposed temperature restrictions allow for more flexibility in application timing than crop growth stage and calendar date restrictions implemented for previously registered OTT dicamba products."

EPA stated that the agency has conducted a "robust human health risk assessment for these proposed products and has not identified any human health or dietary risks of concern.

"Additionally, the agency is proposing to put several measures in place to protect against the ecological risks found in EPA's assessment," an agency announcement stated. "These new products would give farmers an additional tool to help manage crops and increase yields in order to provide a healthy and affordable food supply for our country."

REACTIONS MIXED

EPA's announcement of its proposed decision to approve OTT dicamba products was met with both approval and disapproval.

"Dicamba is a critical crop-protection tool for soybean farmers, particularly in managing herbicide-resistant weeds like Palmer amaranth. These aggressive weeds can quickly overtake fields, competing with soybeans for sunlight, water and nutrients, and ultimately leading to significant yield losses," wrote a spokesperson for the American Soybean Association in a statement sent to DTN. "While ASA is still reviewing the details of EPA's long-anticipated proposed re-registration decision, we recognize the agency has conducted a robust scientific assessment to evaluate and address potential risks associated with over-the-top dicamba use."

Registrants BASF and Bayer also released statements:

"BASF remains committed to a science-based decision-making process and working with regulatory authorities and other stakeholders throughout this process to ensure OTT uses of dicamba remain an option for farmers in the future," wrote a BASF spokesperson.

"We're pleased to see that the EPA has made significant progress and opened a public comment period for low-volatility dicamba herbicides to be used over the top of dicamba-tolerant cotton and soybeans. This technology provides tremendous value to soybean and cotton farmers across the U.S.," wrote a spokesperson for Bayer. "We believe the EPA will benefit from hearing from those closest to the technology. This will help to ensure any decisions regarding the registration of dicamba are fully informed by those who rely on this important tool. Even a simple comment explaining the important role dicamba plays on a particular farm can be impactful and useful for the EPA.

"We know how important this technology is for so many growers, and we will continue working diligently to help ensure these low-volatility dicamba herbicides remain available for over-the-top use in 2026 and beyond," the Bayer spokesperson wrote.

However, the news of EPA's registration decision wasn't heralded by all.

"Trump's EPA is hitting new heights of absurdity by planning to greenlight a pesticide that's caused the most extensive drift damage in U.S. agricultural history and twice been thrown out by federal courts," said Nathan Donley, environmental health science director at the Center for Biological Diversity. "This is what happens when pesticide oversight is controlled by industry lobbyists. Corporate fat cats get their payday, and everyone else suffers the consequences."

In addition to the proposed application restrictions, the OTT dicamba products would also have mitigation point requirements to protect threatened and endangered species and their critical habitats as outlined in EPA's Herbicide Strategy. Users of the herbicide would need to achieve three points of runoff/erosion mitigation in general and six points of runoff/erosion mitigation if a field falls within a pesticide use limitation area (PULA).

NEXT STEPS

After considering public comments on the proposed registration and the draft effects determinations, EPA will decide whether the registration action meets the standard for registration under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). If EPA determines that the registration action can be granted, the agency will finalize the biological evaluation.â?¯

If a final biological evaluation finds that dicamba may affect any listed species or critical habitats, then EPA will initiate Endangered Species Act consultation and share its findings with the U.S. Fish and Wildlife Service or the National Marine Fisheries Service (collectively referred to as the Services), as appropriate.

During formal consultation, the Services use the information in EPA's final biological evaluation to inform their biological opinions. They are responsible for making the final jeopardy/adverse modification findings and have the sole authority to do so. If the Services determine in their final biological opinions that additional mitigations are necessary to address any jeopardy or adverse modification determination or to address any incidental take, EPA will work with the registrants to ensure that any necessary registration or labeling changes are made.

To read more about the proposed registration of OTT dicamba and to submit a comment, go here: https://www.regulations.gov/….

The public comment period closes on Aug. 22.

Jason Jenkins can be reached at jason.jenkins@dtn.com

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