Registration of Dicamba for Use on Genetically Engineered Crops
EPA has registered a dicamba formulation, Xtendimax™ with VaporGrip™ Technology, specifically designed to have lower volatility, to control weeds in cotton and soybean plants that have been genetically engineered (GE) to resist dicamba. Additionally, there are restrictions on the product label that will reduce spray drift.
Dicamba is an herbicide that is already registered for a number of uses. This registration will provide an additional tool to reduce the spread of glyphosate resistant weeds. The final decision includes terms and conditions of registration designed to ensure that weed resistance is successfully managed.
EPA accepted public comment on the proposed registration of dicamba for use on these plants earlier in 2016. EPA has analyzed the comments and information received during the public comment period in developing the final registration decision. The final registration decision and supporting documents are available in www.regulations.gov in docket number EPA-HQ-OPP-2016-0187.
Learn more about dicamba for use on genetically-engineered crops and EPA's registration decision:
- What is dicamba?
- What decision is EPA making about dicamba and why is EPA taking this action?
- How does EPA’s action help the problem of herbicide resistant weeds?
- Is dicamba safe?
- How did EPA assess the safety of dicamba for use on GE crops?
- What safety precautions is EPA putting in place for the use of dicamba on GE crops?
- How does EPA’s work relate to what USDA/APHIS is doing in this area?
- How will the use of dicamba on GE cotton and soybeans affect pollinators/bees?
- In what states will dicamba be registered for use on GE crops?
Dicamba is a selective herbicide in the benzoic acid family of chemicals. It is already registered for uses in agriculture, on corn, wheat and other crops. Dicamba is also registered for non-agricultural uses in residential areas, and other sites such as golf courses, mainly to control broadleaf weeds such as dandelions, chickweed, clover and ground ivy.
After completing a rigorous analysis of all the scientific studies, EPA is registering a formula of dicamba diglycoamine salt (DGA) called Xtendimax™ with VaporGrip Technology™, to control weeds in GE dicamba-tolerant cotton and soybeans. This is a new use for the previously approved herbicide dicamba DGA, and is a formulation with an additive to reduce volatility. It will provide an additional tool to help farmers manage weeds that have become resistant to other herbicides.
EPA received applications from Monsanto requesting the use of dicamba DGA on GE cotton and soybeans. Concurrent with the EPA regulatory process, the U.S. Department of Agriculture received applications from Monsanto to introduce into the U.S. market GE cotton and soybeans that would tolerate exposure to dicamba. USDA announced its decision to deregulate these GE crops on January 20, 2015 (2 pp, 200 K, About PDF). These GE cotton and soybean plants are the first developed to be resistant to dicamba and are intended to allow farmers to use dicamba to control the weeds that have developed resistance to glyphosate and other herbicides.
The new uses on GE cotton and soybeans would expand the current timing of dicamba applications to include post-emergence (or over-the-top) to dicamba-tolerant cotton and soybean crops, thereby enhancing the flexibility in weed control.
Weeds that are becoming increasingly resistant to glyphosate-based herbicides are causing a serious problem for farmers. This action will provide an additional tool to reduce the spread of glyphosate-resistant weeds. The decision outlines an Herbicide Resistance Management plan to ensure that use of dicamba on GE cotton and soybeans successfully manages weed resistance problems.
See question 3 for more on how EPA is addressing herbicide resistance.
We are concerned about the possibility that the use of dicamba could result in weeds becoming resistant to dicamba. The final decision includes terms and conditions designed to ensure that weed resistance is successfully managed, including:
- reporting of resistance and performance issues to EPA by the registrant;
- grower education; and
- remediation programs.
Although we find that herbicide resistance is adequately addressed by the required herbicide resistance plan and do not expect off-site incidents to occur due to this registration, we are placing time limits on the registration to allow the agency to make appropriate regulatory changes or to allow the registration to expire if there are problems with off-site incidents or development of weed resistance.
The registration is time-limited and will automatically expire after two years to allow us to either let it expire or easily make necessary changes in the registration. If we grant an amendment to the registration at that point, it has a second automatic expiration date at five years from the original registration date to again allow the registration to expire or to make necessary changes.
The label will also contain information on resistance management consistent with the Weed Science Society of America’s Best Management Practices (BMPs) for comprehensive resistance management approaches.
When used according to label directions, dicamba is safe for everyone, including infants, the developing fetus, the elderly and more highly exposed groups such as agricultural workers. It also meets the safety standard for the environment, including endangered species. We assessed risks from dicamba to endangered species and found that there would be no effect on listed species from this active ingredient in the approved use area when the product is used according to label directions. The decision to register dicamba for use on GE cotton and soybean meets the rigorous Food Quality Protection Act standard.
With dicamba’s large body of scientific information, we:
- Evaluated risks to all age groups, from infants to the elderly, as well as agricultural workers.
- Used conservative estimates for exposures from pesticide drift or movement, food, drinking water and use around homes and public spaces. (Example: We assumed that all cotton and soybeans in the United States would be treated with dicamba, certainly an overestimate of exposure.)
- Aggregated risks, looking at total potential exposure from all these sources.
- Used conservative estimates for impacts on the environment, including risks to endangered species.
Our human health risk assessment for this registration decision included extensive analysis of the potential for risks to people living near treated agricultural fields, including children and adults, from sources such as volatilization and spray drift. Our human health risk assessment showed no exceedance of our levels of concern for human health, resulting in a determination that the pesticide's use, as approved, will not cause health risks to people living near treated fields, even at the edge of those fields. Even so, we added measures to protect against off-site movement of the pesticide:
- Our approval pertains only to a lower volatility dicamba formulation.
- The pesticide may not be applied from aircraft.
- The pesticide may not be applied when wind speed is over 15 mph.
- Only specific nozzles at specified pressures may be used for application.
- A within-field buffer that ranges from 110 to 220 feet, depending on application rate, has been set to protect sensitive areas when the wind is blowing toward them. This will also further protect bystanders and non-target plants.
USDA's Animal and Plant Health Inspection Service is responsible for determining whether to allow the sale of seeds that have been genetically engineered. EPA regulates the pesticide used on those seeds or crops under the Federal Insecticide, Fungicide, and Rodenticide Act and the pesticide residues remaining in or on food from those uses under the Federal Food, Drug, and Cosmetic Act. The two agencies worked closely to ensure a thorough scientific review of the potential impacts on human health and the environment associated with the uses and have shared information and assessments to inform both agencies’ respective regulatory decisions.
On January 20, 2015, the USDA announced its final decision to deregulate the sale of seeds that have been genetically engineered to tolerate dicamba.
Conservative, screening-level risk assessments have determined that this use of dicamba on GE cotton and soybean, when used according to label directions, does not exceed EPA's level of concern for pollinators/bees. Therefore, we expect there will be no adverse impacts to bees and other pollinators. Regardless, we are working aggressively to protect bees and other pollinators from the potential effects of pesticides and are engaged in national and international efforts to address those concerns. We are working with beekeepers, growers, pesticide manufacturers, the USDA and states to apply technologies to reduce pesticide exposure to bees, advance best management practices, enhance enforcement guidance and ensure that real-world pollinator risks are accounted for in our pesticide regulatory decisions.
The registration of the new use for dicamba on GE cotton and soybean will allow use in:(xx pp, yy K, About PDF)
- New Mexico;
- New Jersey,
- New York;
- North Carolina;
- North Dakota;
- South Carolina;
- South Dakota;
- West Virginia; and
Additional states may be added to the labeling once an endangered species assessment is completed and demonstrates that a no effects determination is appropriate for any such state.