Registration of Enlist One and Enlist Duo

Enlist One and Enlist Duo are herbicides used to control weeds in conventional and genetically-modified corn, cotton, and soybean crops. Enlist One, which only contains 2,4-D choline salt (2,4-D), was first registered in 2017. Enlist Duo, which contains 2,4-D and glyphosate dimethylammonium salt (glyphosate), was first registered in 2014.  

In January 2022, EPA renewed time-limited registrations for both products in 34 states. To protect plants and animals, including those that are federally threatened or endangered (listed), the labels include runoff and spray drift measures that all Enlist One and Enlist Duo applicators are required to follow. Additionally, EPA prohibited the use of Enlist One and Enlist Duo in counties where EPA identified risks to on-field listed species that use corn, cotton or soybean fields for diet and/or habitat. Read EPA’s announcement to learn more. 

In March 2022, EPA approved a registration amendment to allow use of Enlist One and Enlist Duo in 128 additional counties that Corteva did not originally propose for use and six counties that EPA originally prohibited from use. Additionally, EPA corrected an oversight on the Enlist One and Enlist Duo product labels by removing prohibitions for two counties in Massachusetts and Rhode Island. Enlist products are not registered for use in the state of Massachusetts or Rhode Island, and therefore, Enlist products remain prohibited in all counties of these states. Read EPA's announcement to learn more.

The final registration decision document and supporting materials can be found in docket EPA-HQ-OPP-2021-0957.

1. What are Enlist One and Enlist Duo used for?
2. Do these products present risks to human health?
3. Do these products present risks to the environment?
4. What measures are included on the product labels to protect non-target plants and animals from off-field movement of Enlist herbicides?
5. How is EPA protecting listed species and their designated critical habitats?
6. What measures are included on the Enlist labels to protect pollinators?
7. Prior to application, do applicators need to consider anything beyond the product label?
8. How is EPA addressing the issue of herbicide-resistant weeds?
9. How do EPA and the U.S. Department of Agriculture (USDA) work together to regulate Enlist-related products?
10. Enlist One and Enlist Duo are approved for use in which states?
11. Is the active ingredient in these products, 2,4-D, the same as “Agent Orange?”

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1. What are Enlist One and Enlist Duo used for?

Enlist One and Enlist Duo are for use after weeds emergence on genetically-modified corn, soybean, and cotton crops. These products can also be used before weeds emergence on conventional corn, cotton, and soybean crops and fallow cropland that will be planted with these crops.  

The products were identified by EPA as important tools to address weed control for species that have developed resistance to multiple herbicides. The active ingredient, 2,4-D, which is in both Enlist One and Enlist Duo, provides control of broadleaf weeds including glyphosate-resistant weeds like Palmer amaranth. The active ingredient, glyphosate, which is only in Enlist Duo, provides control of both grass weeds and broadleaf weeds. 

2. Do these products present risks to human health?

EPA conducted comprehensive human health risk assessments in the past to evaluate the potential risk these pesticides pose to humans. The Agency determined that, when used as directed on the label, Enlist One and Enlist Duo pose low risk to human health. 

3. Do these products present risks to the environment?

To evaluate the proposed uses of the Enlist products, EPA completed a comprehensive ecological risk assessment that assessed the risks of 2,4-D and glyphosate. EPA also evaluated the potential effects of these products on listed species, and their designated critical habitats, and initiated Endangered Species Act (ESA) consultation with the U.S. Fish and Wildlife Service (FWS). 

EPA's ecological assessment found potential direct risks to plants and plant communities in terrestrial and wetland environments from pesticide runoff (i.e., pesticide carried off the application site following rainfall or irrigation). EPA’s ecological assessment also found potential direct risks to on-field animals (i.e., birds, amphibians, reptiles, mammals, and terrestrial invertebrates) that use corn, cotton and soybean fields for diet and/or habitat. EPA did not identify direct risks to off-field animals, however the impacts to plant and plant communities may have an indirect effect to off-field animals in terrestrial and wetland environments. 

Based on these findings, EPA implemented a variety of protective measures on the Enlist product labels. 

4. What measures are included on the product labels to protect non-target plants and animals from off-field movement of Enlist herbicides?

EPA established many protective measures to reduce off-field movement on the original Enlist product registrations, including the requirements that:

• Enlist herbicides may not be applied from aircraft; 
• Ground spray applications cannot be made when winds are over 15 mph;
• Users can only use approved tank mixes;
• Applicators may only use approved nozzles at specified pressures; and
• Applicators must maintain a 30-foot in-field buffer for areas downwind of application.

Additionally, EPA’s 2022 registration action established new protective measures to reduce pesticide runoff. These measures are required nationally and include:

• Prohibiting Enlist product application when rainfall is expected to occur within 48 hours and when soil is at field capacity (soil can no longer absorb water);
• Prohibiting irrigation that would result in runoff within 48 hours after the application of the Enlist herbicide products; and
• Requiring users to select from a list of runoff reduction measures to reduce 2,4-D and glyphosate concentrations in runoff, while also providing users with flexibility.

5. How is EPA protecting listed species and their designated critical habitats?

The label restrictions that address potential risk from run-off and spray drift will also provide protection to listed species and their designated critical habitat. In addition, the Enlist labels also prohibit the use of Enlist One and Enlist Duo in counties where EPA expects the use of Enlist products would likely affect or jeopardize on-field listed animal species that use corn, cotton or soybean fields for diet and/or habitat. Read page 16 of the new Enlist One label and page 16 of the new Enlist Duo label to see which counties remain prohibited. 

With these control measures in place, EPA expects the use of these products will not likely lead to jeopardy of listed species or to the destruction or adverse modification of designated critical habitats. EPA also anticipates that the protective measures will reduce the potential for unintentional harm (i.e., “take”) to individuals of these listed species and their critical habitats. 

6. What measures are included on the Enlist labels to protect pollinators?

In addition to terms and mitigations to ensure protection of listed species and critical habitat, EPA has required additional mitigation and education for the protection of pollinators. 

Specifically, EPA has implemented a timing restriction for Enlist cotton and Enlist soybean crops to limit applications of these products while the crops are flowering. EPA has also determined that Corteva must develop, implement, maintain, and annually update a pollinator protection stewardship plan. The purpose of this plan is to address potential impacts from this product’s use to insect pollinators, including bees and butterflies. This plan must include education materials that describe the importance of pollinator protection in agriculture and best management practices to reduce potential pesticide exposure to pollinators including, but not exclusive to, to monarch butterflies. 

Education materials must also describe label provisions intended to minimize the potential for product exposure to pollinators, including updated environmental hazard and non-target organism advisory statements, and new application timing restrictions. Additionally, the pollinator protection stewardship plan must include conservation activities that result in meaningful restoration of habitat used by monarch butterflies and other insect pollinators to address potential impacts from this product’s use, taking into account species’ range and habitat requirements. 

7. Prior to application, do applicators need to consider anything beyond the product label?

Yes. As specified on the label, the user must visit Bulletins Live 2 within three months of the intended application, in order to confirm there are not additional use restrictions for their specific geography. The Bulletins Live 2 webpage requires the user to provide the location of application, month of application, and the EPA Registration number for the product (e.g., 62719-649 for Enlist Duo and 62719-695 for Enlist One). The user should download the printable bulletin for their records. If no additional restrictions are indicated in Bulletins Live 2, the user must still adhere to the requirements on the label. If additional restrictions are indicated within Bulletins, the applicator must follow the restrictions stated on the label as well as any additional limitations or mitigations described in Bulletins Live 2. 

8. How is EPA addressing the issue of herbicide-resistant weeds?

To maintain Enlist herbicides as a useful tool in the face of the increasing development of herbicide resistance in problematic weeds, additional scouting requirements have been added to the herbicide resistance requirements labeling. The scouting requirements are aimed at prolonging the lifetime of 2,4-D choline over-the-top use by targeting applications to field conditions and identifying escapes in an attempt to find resistant populations before they become widespread. The revised label includes the following use directions: 

“To aid in the prevention of developing weeds resistant to this product, the following steps must be followed: 

• Scout fields before application to ensure herbicides and rates will be appropriate for the weed species and weed sizes present.
• Scout fields after application to detect weed escapes or shifts in weed species.”

Additionally, EPA has made changes to the annual reporting and testing requirements associated with the herbicide resistance management plan, to help facilitate active monitoring of the continued development of herbicide resistance that may change the associated benefits of Enlist One and Enlist Duo. These changes are explained in more detail in Section 10.5 of the Enlist decision document.  

9. How do EPA and the U.S. Department of Agriculture (USDA) work together to regulate Enlist-related products?

EPA registers Enlist herbicides and sets safe levels for Enlist herbicide residues that may remain in or on food from those uses and assesses the potential environmental impacts from the use of the Enlist herbicide products. USDA regulates seed that is genetically-modified to be tolerant of Enlist herbicides. 

10. Enlist One and Enlist Duo are approved for use in which states?

The federal label allows use of Enlist One and Enlist Duo in the following states: Alabama, Arkansas, Arizona, Colorado, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia, West Virginia and Wisconsin. 

However, EPA has prohibited the use of Enlist One and Enlist Duo in counties where EPA expects the use of Enlist products would likely affect or jeopardize on-field listed animal species that use corn, cotton or soybean fields for diet and/or habitat. Read page 16 of the new Enlist One label and page 16 of the new Enlist Duo label to see which counties remain prohibited. 

11. Is the active ingredient in these products, 2,4-D, the same as “Agent Orange”?

No. “Agent Orange” was a mixture of two different herbicides, 2,4,5-T and 2,4-D, as well as kerosene and diesel fuel. Agent Orange contained high levels of dioxin, a contaminant found in 2,4,5-T that causes cancer and other health concerns in people. EPA canceled all uses of 2,4,5-T in 1985 because of these risks.