In a move that has stirred both anticipation and apprehension within the agricultural community, the Environmental Protection Agency (EPA) opened a public comment period in late July 2025 on its proposal to register three dicamba-based pesticide products for over-the-top use on dicamba-tolerant soybean and cotton seeds. This development comes after a hiatus in dicamba availability for such use since 2024, following a federal court’s decision to overturn the registered labels for three dicamba pesticides: XtendiMax, Engenia, and Tavium.
Dicamba, an herbicide with a history dating back to the 1960s, has long been used to control broadleaf weeds in various crops. However, its over-the-top use on crops, approved for the first time in 2016, has been mired in controversy and legal challenges. The EPA’s recent proposal includes new mitigation measures aimed at reducing off-target impacts and fortifying the label’s legal robustness.
The journey to this point has been tumultuous. Initially, dicamba was used as a preemergent, applied before planting to avoid volatilization and drift. However, the introduction of genetically modified dicamba-resistant soybean and cotton seeds in 2015 paved the way for over-the-top dicamba applications. The EPA’s 2016 approval of dicamba-based pesticides for this purpose sparked immediate legal challenges, with environmental plaintiffs arguing violations of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Endangered Species Act (ESA).
The legal battles culminated in a 2020 decision by the Ninth Circuit Court of Appeals, which vacated the registration of XtendiMax, Engenia, and FeXapan. Despite EPA’s subsequent re-approval of XtendiMax and Engenia for the 2021-2025 growing seasons, another lawsuit ensued. In February 2024, a federal court in Arizona vacated the registration of XtendiMax, Engenia, and Tavium, citing EPA’s failure to comply with FIFRA’s procedural requirements.
Following this ruling, the pesticide manufacturers resubmitted their applications. Bayer, BASF, and Syngenta sought approval for XtendiMax, Engenia, and Tavium, respectively. After a review period, the EPA proposed to unconditionally register all three pesticides, a significant shift from previous conditional registrations.
The EPA’s proposal includes new mitigation measures to address volatilization and endangered species exposure. These measures are part of the EPA’s broader strategy to comply with the ESA, which requires federal agencies to ensure their actions do not jeopardize protected species. The proposed labels for dicamba will include application restrictions, such as a maximum application rate of 0.5 pounds of dicamba per acre, to minimize environmental impact.
The implications of this proposal are substantial. An unconditional registration would provide long-term availability of dicamba for over-the-top use, subject to a fifteen-year review cycle. This could offer farmers a reliable tool for weed management, provided the label’s mitigation measures effectively reduce off-target impacts. However, the proposal’s success hinges on its ability to withstand potential legal challenges and the EPA’s commitment to enforcing the new mitigation measures.
As the public comment period unfolds, stakeholders from the agricultural, environmental, and legal sectors will scrutinize the proposal. The outcome will shape the future of dicamba use and set a precedent for the registration of pesticides with similar environmental implications. The EPA’s decision to include new mitigation measures reflects a proactive approach to balancing agricultural needs with environmental protection, but the ultimate test will be in the implementation and outcomes of these measures in the field.