Citing the inevitability of “superweeds” and calling the product a “life preserver” for fatally flawed technology, environmentalists urge the EPA not to register a new Dow AgroSciences herbicide for GE corn and soybeans.
By Phil Zahodiakin | August 22, 2014
Environmentalists warn that an herbicide designed to work with new varieties of genetically engineered (GE) corn and soybeans should not be registered by the Environmental Protection Agency because, like other widely-used herbicides for GE crops, it will gradually promote the emergence of “superweeds” resistant to the new herbicide.
The herbicide at issue is Dow AgroSciences’ Enlist Duo, whose active ingredients are two “old” chemicals: glyphosate (best known by the trade name “Roundup”) and 2,4-D. The herbicide would be applied in fields planted with Enlist Corn and Enlist Soybeans – which Dow has engineered to tolerate the product.
The first commercial applications of 2,4-D date back to the mid-1940s, but the chemical gained notoriety due to its use in a Vietnam War-era defoliant: Agent Orange. Although 2,4-D was not the only herbicide in Agent Orange, the product was contaminated with dioxin — a potent carcinogen — as a byproduct of the production process.
Glyphosate, meanwhile, has long been the dominant herbicide in GE agriculture. Decades of home-and-garden use in addition to agricultural applications have resulted in the inevitable: weeds are becoming resistant to glyphosate, with resistant species having been detected in over half the states.
Killing resistant weeds
The 2,4-D in Enlist Duo is intended to kill all the weeds in a field, whether or not they’ve become resistant to glyphosate. The Agriculture Department is expected to issue a decision “deregulating” Enlist Corn and Enlist Soybeans, which could then be planted anywhere in the United States.
In its April 30 proposal to register Enlist Duo, however, the EPA says it would limit its sale and use (at least initially) to Illinois, Indiana, Iowa, Ohio, South Dakota and Wisconsin. Those are the states where the agency has enough data, it says, to conclude that the new 2,4-D uses won’t put endangered species at risk.
Because one or more of the seven weed species known to resist glyphosate have turned up in 27 states, growers pushed back against the geographic restriction in comments submitted to thepublic docket, which closed on June 30. Conversely, environmental groups have questioned the adequacy of the EPA’s endangered species finding as well as many other agency conclusions supporting its registration proposal.