Enlist Duo Update

EPA Finds No Synergy, Enlist Duo Registration Moves Ahead

Emily Unglesbee
By  Emily Unglesbee , DTN Staff Reporter
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Pending final registration of Enlist Duo, Dow hopes to sell Enlist cotton for the 2017 season. Enlist corn and soybeans are still awaiting Chinese import approvals. (DTN photo by Pamela Smith)

ROCKVILLE, Md. (DTN) -- After a year-long legal pause, Enlist Duo's registration is back on track.

The herbicide, a mix of glyphosate and 2,4-D choline created by Dow AgroSciences, is designed to be applied over top the company's Enlist corn, soybean and cotton crops, which are genetically engineered to tolerate it.

Enlist Duo was registered for use on Enlist corn and soybeans in a total of 15 states before the EPA ordered a court to pull its registration in November of 2015, due to concerns over "synergistic" effects, or increased toxicity, of the combined ingredients.

Ultimately, the court denied that order, and Dow submitted additional data to the EPA to address these concerns, from which the agency has now concluded that there is no evidence of synergy between the ingredients. EPA is also proposing to register Enlist Duo for corn and soybeans in 19 additional states (for a total of 34) and registering it for use on Enlist cotton in all those states, as well.

The proposed registration is up for public comment through Dec. 1, when the EPA will review comments and reach a final registration decision.


EPA's proposed new registration for Enlist Duo would allow its use on Enlist corn, soybeans and cotton fields in Alabama, Arizona, Arkansas, Colorado, Delaware, Illinois, Indiana, Iowa, Florida, Georgia, Louisiana, Kansas, Kentucky, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, North Carolina, North Dakota, New Jersey, New Mexico, New York, Oklahoma, Ohio, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia, West Virginia and Wisconsin.

"For the 2017 season, PhytoGen will be accelerating sales of Enlist cotton with Genuity Roundup Ready Flex and WideStrike 3 Insect Protection," company representatives told DTN in an email. Growers will be permitted to use Enlist Duo on the crop, once the registration is finalized, they added.

Enlist corn and soybean traits are still awaiting import approvals from China, which has slowed their commercialization. However, the company said it "expects full commercialization of Enlist corn in 2017, pending import approvals in China," and "is ready for full commercialization of both SmartStax Enlist corn and PowerCore Enlist corn once import approvals are obtained."

Dow press releases said that it "expects to launch Enlist soybeans as early as 2017, pending import approvals."

One Enlist cotton variety, PHY 490 W3FE, was sold in 2016, despite the fact the company's corresponding 2,4-D herbicide was not available for use in-season on the trait at the time. Dow representatives told DTN enough was planted to gain broad geographic exposure through targeted growers throughout the cotton belt from Arizona to Virginia.

The PhytoGen cotton development specialist team selected growers who met specific launch criteria to avoid potential uses of older, more volatile 2,4-D formulations. Cotton plants (without the Enlist trait) are very susceptible to 2,4-D, a primary ingredient in Enlist Duo, as are a number of other horticultural and row crops. The company also runs a program called "Enlist Ahead," to train applicators and growers on best management practices.


The initial legal hiccup in Enlist Duo's registration originated from EPA's discovery of information in Dow's patent application for the herbicide, wherein the company referenced evidence of "synergistic" effects between the two ingredients. The term "synergistic" is used by weed scientists to describe when two herbicides work better when applied together than when each is applied alone.

The agency requested that Dow provide "additional formulation-specific data" to "address any uncertainty in the risk assessments due to the 'synergistic effects' claims made in patent applications for the two constituent herbicides and confirm whether the original buffers were still appropriate."

Dow said that original patent application statement was based on a "limited dataset." A full review of additional data, some of it generated after the patent was filed, shows that in Enlist Duo's formulation, "synergism that could impact non-target threatened or endangered plant species does not exist."

Now satisfied that no risk is posed by synergistic effects within Enlist Duo, and that its original risk assessments of the herbicide were correct, EPA is moving forward with the same buffer requirements, along with specific nozzle and wind speed requirements designed to minimize off-target drift.

The new registration also calls for a specific herbicide-resistance plan requiring Dow to investigate any reports of herbicide efficacy problems and submit annual reports on them to the EPA.

See the proposed registration document here: http://bit.ly/… and the EPA's docket on this decision, which is available for public comment for 30 days, here: http://bit.ly/….

Emily Unglesbee can be reached at Emily.unglesbee@dtn.com

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Emily Unglesbee