Registration of Dicamba for Use on Dicamba-Tolerant Crops
In 2018, EPA extended the registration for two years for over-the-top use (use on growing plants) of dicamba to control weeds in cotton and soybeans genetically engineered to tolerate dicamba. Extensive collaboration with the pesticide manufacturers, farmers, state regulators, and other stakeholders informed EPA’s decision. The registration requires label updates that add protective measures to further minimize the potential for off-site plant damage.
View the documents supporting this decision:
In 2019, EPA registered a product containing a combination of dicamba and S-metolachlor for over-the-top use on dicamba-tolerant cotton and soybeans. This combination of active ingredients is currently an approved tank mix, and as such, is already used over the top on cotton and soybeans. See question #3 below for more information this product.
The registration for all these dicamba products will automatically expire on Dec. 20, 2020, unless EPA extends the registration.
Learn more about dicamba for use on dicamba-tolerant crops:
- What is dicamba?
- What additional steps is EPA taking to further minimize damage to non-target crops resulting from dicamba used on dicamba-tolerant crops (over-the-top applications)?
- How do the requirements for the combination of dicamba and S-metolachlor differ from the requirements for other dicamba products?
- What are EPA’s next steps?
- Are dicamba residues on food safe?
- How will the use of dicamba on dicamba-tolerant cotton and soybean affect pollinators, including bees?
- In what states is dicamba registered for use on dicamba-tolerant cotton and soybean?
1. What is dicamba?
Dicamba, a benzoic acid, is a widely used herbicide on agricultural crops, fallow land, pastures, turfgrass and rangeland. It was first registered in the U.S. in 1967.
Historically, most dicamba applications occurred in late winter or early spring for removal of broadleaf weeds prior to planting crops. It is registered for use in agriculture on corn, wheat, cotton, soybeans and other crops.
In 2016, EPA first registered certain dicamba formulations for “over-the-top” use on growing dicamba-tolerant cotton and soybean plants during the 2017 growing season.
In 2017, after many alleged non-target incidents where sensitive plants were injured, EPA reached an agreement with manufacturers on additional measures to minimize the potential for damage to neighboring crops from the use of over-the-top dicamba formulations to control weeds in dicamba-tolerant cotton and soybeans. The registrants agreed to registration and labeling changes for the 2018 growing season, including making these products restricted-use and requiring record-keeping and additional measures to prevent spray drift .
Only dicamba products registered for use on dicamba-tolerant cotton and soybeans can be applied over-the-top. It is a violation of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) to treat any dicamba-tolerant crop with a dicamba product that is not registered for use on genetically engineered crops.
Dicamba is also registered for non-agricultural uses in residential areas and other sites, such as golf courses. At these types of sites, it is primarily used to control broadleaf weeds such as dandelions, chickweed, clover and ground ivy.
2. What additional steps is EPA taking to further minimize damage to non-target crops resulting from dicamba used on dicamba-tolerant crops (over-the-top applications)?
EPA worked with pesticide manufacturers, farmers, state regulators and other stakeholders to develop the following label changes for over-the-top use of dicamba on dicamba-tolerant cotton and soybeans through the 2020 growing season:
- Only certified applicators may apply dicamba over the top. (Those working under the supervision of a certified applicator may no longer make applications.)
- Over-the-top application of dicamba on soybeans 45 days after planting and cotton 60 days after planting is prohibited.
- For cotton, we reduced the number of over-the-top applications allowed from four to two (soybeans remain at two over-the-top applications).
- Application will be allowed only from one hour after sunrise to two hours before sunset.
- In counties where endangered species may exist, the downwind buffer will remain at 110 feet and there will be a new 57-foot buffer around the other sides of the field. The 110-foot downwind buffer applies to all applications, not just in counties where endangered species may exist.
- The training period is clarified to require annual applicator certification for 2019 and beyond, ensuring consistency across all three products.
- We improved tank clean-out instructions for the entire system.
- We improved labels enhanced to improve applicator awareness of the impact of low pH on the potential volatility of dicamba.
- Labels have been cleaned up and made more consistent to improve compliance and enforceability.
3. How do the requirements for the combination of dicamba and S-metolachlor differ from the requirements for other dicamba products?
Due to the requirements for S-metolachlor, this product will have some different directions for use, such as an earlier use season and shorter application windows, than the other dicamba products registered for use on dicamba-tolerant crops. These differences are outlined in the table below.
This product will otherwise be registered with the same label restrictions, training needs, data requirements, and other conditions as the currently registered dicamba products.
Dicamba and S-metolachlor mixture
Other dicamba products
Application timing – Soybean
Until plant develops four leaves (V4), or 45 days after planting, whichever comes first
Until flowering begins (R1), or 45 days after planting, whichever comes first
Application timing – Cotton
Until plant develops six leaves, or 60 days after planting, whichever comes first
Until flowering begins (mid-bloom stage), or 60 days after planting, whichever comes first
Application permitted to second crop in the same growing season
Number of applications per growing season
Total amount applied per growing season
0.5 lb of dicamba per acre
1.0 lb of dicamba per acre
4. What are EPA’s next steps?
The registration for all dicamba products registered for over-the-top use on genetically engineered cotton and soybeans will automatically expire on Dec. 20, 2020, unless EPA acts to extend it. EPA will continue to coordinate with states and other stakeholders to clarify label interpretations and regulatory oversight for dicamba applications throughout the 2020 season.
5. Are dicamba residues on food safe?
Yes. EPA performed the analysis required by the Federal Food, Drug and Cosmetic Act (FFDCA) and determined that residues on food are “safe” – meaning that there is a reasonable certainty of no harm to people, including all reasonably identifiable subpopulations, including infants and children, from dietary and all other non-occupational exposure to dicamba.
6. How will the use of dicamba on dicamba-tolerant cotton and soybean affect pollinators, including bees?
Conservative screening-level risk assessments (assessments that exaggerate anticipated exposure) have determined that this use of dicamba on dicamba-tolerant cotton and soybean, according to label directions, does not exceed EPA's level of concern for pollinators, including bees. Therefore, we expect there will be no adverse impacts to bees or other pollinators.
7. In what states is dicamba registered for use on dicamba-tolerant cotton and soybean?
The registration for over-the-top use of dicamba on dicamba-tolerant cotton and soybean allows for use in:
- New Mexico;
- New Jersey,
- New York;
- North Carolina;
- North Dakota;
- South Carolina;
- South Dakota;
- West Virginia; and