The U.S. Environmental Protection Agency (EPA) has approved labeling amendments that further restrict the use of over-the-top dicamba in Iowa, Illinois, Indiana and South Dakota. The Iowa, Illinois and Indiana amendments were requested by product registrants following discussion with those states. The South Dakota amendment was proposed by the state to the registrant. All amendments are intended to reduce risks from the use of over-the-top dicamba, an herbicide sprayed over-the-top of genetically engineered soybeans and cotton after the crops have emerged from the ground to control certain types of broadleaf weeds.
The revised labeling prohibits the use of over-the-top dicamba application on dicamba-tolerant crops after June 12 in Iowa, Illinois and Indiana and after June 20 in South Dakota. This restricts over-the-top dicamba application to earlier in the growing season, when temperatures are likely to be lower, and is intended to reduce the potential for dicamba to volatilize and drift off-site. 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 and other requirements are outlined in the terms and conditions of the amended registration.
These amendments follow amendments EPA approved for Minnesota and Iowa in March 2022. The amendment for Minnesota remains the same. However, for Iowa, the new amendment supersedes the previous amendment. Therefore, over-the-top dicamba can no longer be applied after June 12 in Iowa.
As EPA continues to review dicamba-related incidents and considers the regulatory tools available to further address these incidents, the Agency is ready to support state-implemented restrictions that reduce risks from the use of over-the-top dicamba. If a state wishes to further restrict the over-the-top uses of dicamba, it may use FIFRA section 24(a) to do so, or registrants and states can work together to submit a label amendment containing state-specific restrictions for EPA approval.
To view the amended labeling, visit docket EPA-HQ-OPP-2020-0492 at www.regulations.gov.
Background on Dicamba-Related Incidents
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 that found senior political leadership’s involvement in the decision led to “...changes to or omissions from scientific documents, including omissions of some conclusions addressing stakeholder risks.” The political interference that occurred with the 2018 dicamba decision happened despite the best efforts of EPA’s career scientists and managers to recommend a different approach.
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 from 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 to prevent off-target movement and damage to non-target crops and other plants.
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. However, despite the control measures implemented in EPA’s October 2020 dicamba registration decision, incident reports from the 2021 growing season showed little change in the number, severity, and/or geographic extent of dicamba-related incidents when compared to the reports the Agency received before the 2020 control measures were required. EPA has not yet fully analyzed 2022 incident data, but based on incident reports received and discussions with state regulators, weed scientists, and academics, EPA has reason to believe dicamba-related incidents continued through the 2022 growing season as well.
EPA’s Continued Review of Dicamba
Given the incident information obtained from recent growing seasons, EPA is reviewing whether dicamba products registered for over-the-top use pose unreasonable risks to non-target crops and other plants or to federally listed species and their designated critical habitats. EPA is also evaluating all of its options for addressing future dicamba-related incidents.
Currently, EPA is working to understand the geographic variability of dicamba-related incidents. Additionally, EPA is analyzing how these incidents may relate to dicamba’s chemical properties. As the Agency progresses in its review, it will continue to consider if additional information could be provided to assist in EPA’s evaluation.
Moreover, all uses of dicamba, including pre-emergent and over-the-top applications of the pesticide, are being assessed in registration review. Registration review is a statutory program in which EPA reviews and updates, as necessary, older pesticide registrations based on current scientific standards to ensure that they continue to meet FIFRA’s registration standard.
As part of the registration review process, EPA recently accepted public comment on the second addendum to the 2016 draft human health risk assessment and a draft ecological risk assessment for dicamba. EPA will continue the registration review process by publishing the proposed interim decision (PID). The PID will address public comments on the risk assessments and may propose risk mitigation to address any potential risks of concern identified in the dicamba draft risk assessments. The public will have an opportunity to comment on the PID.
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