New combination herbicide for crops gains federal approval

A new herbicide, long awaited by farmers as a tool to fight "superweeds" but long opposed by environmental groups, has received final federal approval and is likely headed for Midwestern fields next year.

Enlist Duo, manufactured by Dow AgroSciences, could become an important competitor to Monsanto's popular Roundup Ready system, which has dominated the corn and soybean market since the late 1990s.

The Environmental Protection Agency gave the green light last week for Dow AgroSciences to register Enlist Duo, clearing the way for the subsidiary of Dow Chemical to sell it in combination with new genetically engineered corn and soybean seeds.

The product will be initially allowed in six states: Wisconsin, Iowa, South Dakota, Illinois, Ohio and Indiana. Approval is pending in Minnesota and nine other states where a public comment period is now underway.

Minnesota Soybean Growers Association President George Goblish said that soybean farmers are excited about the decision, even though they won't be able to take advantage of the product yet. "The Enlist Duo registration unties farmers' hands and gives them another option to combat weed issues," he said.

Minnesota farmers grow more than 7 million acres of soybeans and about 8.5 million acres of corn.

Enlist Duo combines two older weedkillers into one product: an herbicide component known as 2,4-D, and glyphosate, the chief ingredient in Roundup.

The herbicide would be sprayed early in the growing season, ideally when weeds and crops are 2 to 4 inches tall. The spraying would not affect Enlist corn and soybean plants because their seeds have genetically-engineered traits to tolerate the new herbicide formulation. The U.S. Department of Agriculture approved the seeds last month.

The decision to approve the herbicide "is protective of everyone and the environment," said Jim Jones, assistant EPA administrator for the Office of Chemical Safety and Pollution Prevention. The decision was based on "sound science," he said, and evaluated the risks to all age groups from infants to elderly, as well as to farm workers and wildlife, including endangered species.

Environmental groups condemned the decision, and said that EPA ignored serious health risks, especially to children, that are associated with 2,4-D. Critics said the chemical has been linked to reproductive problems, non-Hodgkin's lymphoma and Parkinson's disease.

"Giving a chemical company the green light to bring a known harmful weed killer to market for use on millions of acres of crops puts public health and the environment in danger," said Mary Ellen Kustin, senior policy analyst for the Environmental Working Group in Washington, D.C.

Another environmental organization, the Natural Resources Defense Council, filed a lawsuit in D.C. Circuit Court to block use of the herbicide.

Andrew Liveris, Dow's chairman and CEO, said the technology is expected to deliver significant value for the company over the near and far term. "Crossing this final milestone represents a pivotal achievement for Dow," he said in a statement. The company will announce its 2015 market launch for the Enlist system in the coming weeks, officials said.

Dow AgroSciences developed the Enlist system to compete with Monsanto, whose Roundup Ready seeds account for about 90 percent of soybeans and 85 percent of corn planted in the United States each year.

Weeds that are resistant to Roundup have evolved and spread, plaguing farmers in many states, including Minnesota.

"We have our share of problem fields and problem sites where farmers would be very interested in looking at this technology," said Jeff Gunsolus, University of Minnesota Extension agronomy professor and weed specialist.

Gunsolus said that weeds became resistant to Roundup because too many farmers relied on it exclusively, and sometimes applied it too late when weeds were tall, or skimped on the rates, allowing some weeds to survive.

Whether it's Roundup or Enlist Duo or products yet to come, Gunsolus said controlling weeds boils down to giving crops a competitive advantage. Farmers need to know what weeds to target, he said, and then apply different herbicides at different times — once close to planting before weeds have emerged, and once a few weeks later when weeds are growing but still small.

If farmers don't use Enlist Duo correctly according to label, he said, weeds will be able to adapt and become resistant to both glyphosate and 2,4-D.

That's also a major concern of environmental groups. "This continued arms race between chemical companies and superweeds is a threat to sustainable farming and public health," said Kustin, of the Environmental Working Group.

Not far behind Dow AgroSciences, Monsanto is awaiting federal approval for its Roundup Ready Xtend Crop system, which introduces soybeans and cotton engineered to tolerate a combination of the herbicides dicamba and glyphosate.

And Syngenta Seeds Inc. and Bayer CropScience are proposing a soybean genetically engineered to tolerate exposure to the herbicides glufosinate and mesotrione.

Essentially, the companies are engineering seeds and adding traits that allow them to use decades-old herbicides in new ways.

In approving the registration for Enlist Duo, EPA officials added restrictions about setbacks and maximum wind speeds to avoid pesticide drift, and said they will review Enlist Duo in six years rather than the customary 15 years.

Gunsolus said those restrictions are setting a new precedent for the next wave of weed control products.

"It's a big deal in terms of how it's being rolled out," he said. "Time will tell as to how much it's adopted."

Tom Meersman • 612-673-7388