In late July 2025, the Environmental Protection Agency (“EPA”) announced that it had opened a public comment period on its proposal to register three dicamba-based pesticide products for use directly on dicamba-tolerant soybean and cotton seeds. No dicamba pesticide has been available for “over-the-top” use since 2024 after a federal court in Arizona overturned the registered labels for three dicamba pesticides, XtendiMax, Engenia, and Tavium. Although dicamba has been approved for use as a pesticide for decades, it only became available for direct use on crops in 2016. In that time, over-the-top use of dicamba has proven controversial, sparking litigation that has twice resulted in a federal court overturning the registered label. The recent proposal from EPA includes new mitigation measures intended to reduce off-target impacts and create a more legally robust label.

How Did We Get Here?

Dicamba is an herbicide that has been used to control broadleaf weed plants in various food and feed crops in the United States since the 1960s. Historically, dicamba has been used as a preemergent that would be applied to fields in late winter or early spring prior to planting. This is because dicamba has a tendency to volatize, meaning it will evaporate into the air and drift off-target. However, in late 2016, EPA registered for the first time a dicamba-based pesticide product for use directly on crops. The registration, which authorized over-the-top use for the 2017 and 2018 growing seasons, was granted for new low-volatility dicamba products that were intended for use on genetically altered dicamba resistant soybean and cotton seeds which had been approved for sale in 2015.

EPA’s decision to approve some dicamba products for over-the-top use proved controversial and prompted legal challenges. Environmental plaintiffs filed a lawsuit against EPA, claiming that its 2016 registration decision violated both the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”) and the Endangered Species Act (“EPA”). While that lawsuit was ultimately dismissed because it did not reach the trial stage before the 2016 label expired, the same plaintiffs filed another lawsuit making the same arguments to challenge EPA’s 2018 decision to register over-the-top use of dicamba again for another two years. There, the plaintiffs claimed that EPA had violated FIFRA and the ESA by failing to ensure that its registration decision satisfied the requirements of either statute. Ultimately, that lawsuit resulted in a decision from the Ninth Circuit Court of Appeals issued in June 2020 that vacated EPA’s registration decision for three dicamba products, XtendiMax, Engenia, and FeXapan. To learn more about that decision, click here.

Following the Ninth Circuit’s decision, EPA re-approved both XtendiMax and Engenia (a third dicamba-based pesticide, Tavium, has not included in the Ninth Circuit’s decision and remained available for use) for use during the 2021 – 2025 growing seasons. Again, environmental plaintiffs filed a lawsuit, arguing that EPA’s registration decision violated FIFRA and the ESA. The lawsuit was initiated in late 2020, and on February 14, 2024, a federal court in Arizona vacated EPA’s decision to register XtendiMax, Engenia, and Tavium for over-the-top use. In its decision, the court held that EPA had failed to comply with the procedural requirements of FIFRA. Specifically, the court found that EPA had approved the wrong type of label for the three pesticides and that the agency had failed to hold a period of public comment on the registration decision. A more in-depth look at that ruling is available here.

After the Arizona court issued its ruling, the pesticide manufacturers resubmitted applications to EPA to approve dicamba-based products for over-the-top use. Between March and June 2024, Bayer resubmitted a registration application for XtendiMax, BASF resubmitted for Engenia, and Syngenta resubmitted for Tavium. Following a period of review, EPA is now proposing to unconditionally register all three pesticides.

What is EPA Proposing?

On July 23, EPA announced that it is proposing to register XtendiMax, Engenia, and Tavium for over-the-top use on dicamba resistant soybeans and cotton. Unlike previous registrations for over-the-top dicamba products which had conditional registrations, EPA is now proposing to unconditionally register dicamba. Additionally, EPA is proposing new mitigation measures to include on the labels for the three dicamba pesticides intended to both limit volatilization and reduce exposure to endangered species.

FIFRA is the primary federal law regulating pesticide use in the United States. A pesticide may not be sold or distributed for use in the United States until EPA has registered the pesticide’s label under FIFRA. To register a pesticide, FIFRA requires EPA to determine that using the pesticide in its proposed manner “will not generally cause unreasonable adverse effects on the environment.” 7 U.S.C. § 136a(c)(5)(C). FIFRA defines “unreasonable adverse effects on the environment” as “any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of any pesticide[.]” 7 U.S.C. § 136(bb).

The registration process begins when a pesticide manufacturer submits an application to EPA. From there, EPA analyzes various data to determine whether the pesticide satisfies FIFRA’s “unreasonable adverse effects” standard. When registering a pesticide, EPA has two broad options. It can either register the pesticide conditionally or it can register the pesticide unconditionally. A conditional registration is usually more temporary, the label will often have an expiration date, and indicates that EPA requires further data before it can make an unconditional registration. An unconditional registration is more permanent. Unconditional registrations do not have an expiration date, but EPA must evaluate unconditional registrations every fifteen years to ensure that they still meet FIFRA requirements. More information on the FIFRA registration process is available here.

The ESA is one of the main wildlife protection laws in the United States. It is administered jointly by the United States Fish and Wildlife Service and the National Marine Fisheries Services (collectively “the Services”) and requires those agencies to compile a list of species that are at risk of extinction. Once listed, those species receive ESA protection. One of the primary protections that the ESA provides to listed species is the requirement that all federal agencies consult with the Services to ensure that any action an agency authorizes, funds, or carries out will not jeopardize the existence of a protected species. In the past, EPA has struggled to fulfill its ESA consultation responsibilities when taking actions under FIFRA, including registering new pesticide products for use. In an effort to better comply with the ESA, EPA announced in 2022 that it would be developing various mitigation measures to include on pesticide labels in order to reduce pesticide exposure to listed species. Since that announcement, EPA has finalized both an Herbicide Strategy and an Insecticide Strategy that identify such mitigations. Going forward, EPA will apply those strategies to newly registered pesticide products. To learn more about the Herbicide Strategy, click here.

EPA’s proposal to register three dicamba herbicides for over-the-top use is both unconditional and includes mitigation measures from the Herbicide Strategy. By proposing to register the products unconditionally, EPA is seeking a long-term registration decision that will not expire in two to five years like previous over-the-top dicamba registrations. This also indicates that EPA does not believe it needs additional data to conclude that using the three dicamba products in their intended manner will not cause “unreasonable adverse impacts on the environment.” Should the proposed labels be finalized, XtendiMax, Engenia and Tavium would remain available for use for at least fifteen years or unless a court vacates the registration decision.

Like previous labels for over-the-top use of dicamba, the proposed labels include application restrictions intended to reduce the risk of volatilization. Unlike previous labels, the recent proposal incorporates Herbicide Strategy mitigation measures intended to reduce risks to endangered species. Overall, the proposed labels for over-the-top dicamba will require the following:

• A single use maximum application rate of 0.5 pounds of dicamba per acre.
• A limit of two applications with a maximum annual application of one pound of dicamba per acre.
• A prohibition on aerial applications.
• Maintaining a 240-foot downwind buffer.
• The use of an approved drift reduction agency and pH buffering volatility reduction agent added to the tank with higher percentages required as temperature increases.
• No applications at temperatures greater than 95 degrees Fahrenheit.
• Three points of mitigation based on EPA’s runoff and erosion mitigation menu.
• Users must access Bulletins Live! Two and follow any applicable endangered species bulletins; some pesticide limitation areas may require six mitigation points prior to application.
• Applicators must wear baseline attire, personal protective equipment, and chemical-resistant gloves when handling the products; entry to treated areas will be restricted for up to 24 hours after application; and applicators will be required to complete a dicamba-specific annual training and maintain records of all applications.

Some of these mitigations are similar to requirements on previous over-the-top dicamba labels, such as the maintenance of a buffer zone and a requirement for tank-mixing. However, unlike previous over-the-top dicamba labels, this proposal includes a temperature cut off for applications rather than a cut off date, and incorporates additional mitigations to reduce runoff and erosion.

Going Forward

A public comment period on the proposed labels for XtendiMax, Engenia, and Tavium is open through August 22, 2025. After the comment period closes, EPA will decide whether the labels meet the standard for registration under FIFRA and if so, EPA will seek to finalize the action. Information on how to submit a comment can be found here.

Should EPA register the three dicamba products for over-the-top use, it would likely result in over-the-top dicamba being available to farmers for the 2026 growing season. Because EPA has proposed registering the products unconditionally, those labels would remain in place for at least fifteen years unless a court vacates the registration decision. It is likely that a final registration decision for over-the-top dicamba will face a legal challenge. If a lawsuit is filed, it would be significant because it would be the first time an unconditional registration for over-the-top dicamba is subject to litigation, and because it is possible that the court could be asked to consider whether mitigation measures from the Herbicide Strategy satisfy EPA’s responsibilities under the ESA.

To read EPA’s proposal, click here.

To read the text of FIFRA, click here.

To read the text of the ESA, click here.

For more information on pesticides from the National Agricultural Law Center, click here.