U.S. EPA approves label amendments that further restrict the use of over-the-top dicamba in Minnesota and Iowa

The U.S. Environmental Protection Agency (EPA) has approved label amendments that further restrict the use of over-the-top dicamba in Minnesota and Iowa. The amendments, requested by pesticide registrants in consultation with those states, are intended to reduce risks from the use of over-the-top dicamba, an herbicide used to control certain types of broadleaf weeds.

The revised labeling prohibits over-the-top dicamba application:

• On dicamba-tolerant crops after June 20 in Iowa;

• On dicamba-tolerant crops south of Interstate 94 after June 12 in Minnesota (the cut-off date for land north of Interstate 94 remains June 30); and

• When the air temperature is over 85 degrees at the time of application or if the forecasted high temperature of the nearest available location exceeds 85 degrees in Minnesota.

These restrictions are intended to reduce the likelihood of volatility and offsite movement of over-the-top dicamba by avoiding application on days with high temperatures. Among other requirements, the product registrants must add the amended labeling to their training and educational materials and disseminate this information to pesticide authorities and agricultural extension services to assist users in their local area. These label amendments demonstrate EPA’s ongoing commitment to help states address issues related to incidents in their jurisdictions. EPA’s highest priority is to protect human health and the environment, and all pesticide decisions must be consistent with this principle.

In December 2021, EPA released a summary of dicamba-related incident reports from the 2021 growing season obtained from pesticide registrants, States, the general public, and non-governmental organizations. Despite the control measures implemented in EPA’s October 2020 dicamba registration decision, incidents from the 2021 growing season show little change in number, severity, or geographic extent of dicamba-related incidents when compared to the reports the Agency received before the 2020 control measures were required. EPA received approximately 3,500 dicamba-related incident reports from the 2021 growing season, including approximately 711 incidents reported in Minnesota and 528 incidents reported in Iowa. Additionally, more than 280 incident reports came from counties where additional restrictions are required to protect endangered species when dicamba is applied to dicamba-tolerant soybean and cotton crops, including approximately 34 incident reports in Minnesota and 69 in Iowa.

Based on prior research and numerous stakeholder meetings, EPA has reason to believe the number of incidents reported significantly understates the actual number of incidents related to dicamba use. For example, in a 2020 memo, EPA estimated that one in 25 dicamba incidents was reported to EPA. No evidence available to EPA suggests that underreporting has changed.

Given the incident information obtained from the 2021 growing season, EPA is reviewing whether over-the-top dicamba can be used in a manner that does not pose unreasonable risks to non-target crops and other plants, or to listed species and their designated critical habitats. EPA is also evaluating all of its options for addressing future dicamba-related incidents.

As EPA considers the regulatory tools available to further address dicamba-related incidents, the Agency continues to work with states and registrants to assess and implement additional restrictions. If a state wishes to further restrict or narrow the over-the-top uses of dicamba, it may use FIFRA section 24(a) to do so, or like this action, it may work with registrants to submit a label amendment containing state-specific restrictions for EPA approval.

To view the label amendments, visit docket EPA-HQ-OPP-2020-0492 at www.regulations.gov.

Background on Dicamba

In 2017 and again in 2018, EPA amended the registrations of all over-the-top dicamba products following reports that growers had experienced crop damage and economic losses resulting from the off-site movement of dicamba. The U.S. Court of Appeals for the Ninth Circuit vacated the 2018 registrations in June 2020 on the basis that “EPA substantially understated risks that it acknowledged and failed entirely to acknowledge other risks.” Days after the court’s decision, EPA issued cancellation orders for the affected products that addressed existing stocks. Additionally, the 2018 decision was the focus of an Inspector General report.

In October 2020, EPA issued new registrations for two dicamba products and extended the registration of an additional dicamba product. These registration decisions were made with some input of EPA’s career scientists and managers and were expected to address the risk concerns noted by the Ninth Circuit. All three registrations included new measures that the Agency expected would prevent off-target movement and damage to non-target crops and other plants.