The Enlist System of 2,4-D resistant corn and soybeans has taken another step toward becoming commercially available for farmers to plant. The Enlist System for weed control, developed by Dow AgroSciences, is going through the regulatory process, seeking federal approval for use in the marketplace.
USDA's Animal and Plant Health Inspection Service on January 3, 2014 published a draft environmental impact statement as part of the process for potential deregulation of the seeds, which can now be used only in tightly controlled field trials. Deregulation would allow commercial development of the seeds. USDA has oversight of the seeds; the U.S. Environmental Protection Agency is conducting a separate review of 2,4-D—although EPA previously has found this herbicide safe to use. The EPA is looking at the impact of expanded use of 2,4-D and will issue a report on that topic, which is expected to be released for public comment in coming months. EPA and USDA/APHIS are expected to make final decisions simultaneously on use of the chemical herbicide and 2, 4-D resistant seeds. The timing on the release of their final decision is uncertain.
Another step closer to 2, 4-D resistant crops was taken by USDA last week
USDA is seeking review and comment from the public on the possibility of deregulating corn and soybean seed that is resistant to 2,4-D. APHIS released the draft environmental impact statement as part of the Enlist system's review to determine the deregulation. The statement will be available for public review and comment 45 days from first date of publication in the Federal Register. The document is expected for be posted on the EPA site for review beginning January 10, 2014.
USDA/APHIS has four alternatives to consider: keep all of the genetically engineered corn and soybean plants under regulation, deregulate the corn plant only; deregulate the soybean plant only or deregulate both corn and soybeans.
As USDA/APHIS seeks public comment, EPA is concurrently conducting risk assessments on the proposed new use of 2, 4-D herbicide. USDA's analysis will include thorough review of any potential human health and environmental risks associated with the application of 2,4-D to the genetically engineered corn and soybean plants.
Critics of these new genetically engineered crop seeds are concerned their widespread planting by farmers will lead to more problems with weeds developing resistance to herbicide.
An interesting side note, one of the areas of concern that has been brought up by some people is that the increased use of 2,4-D will lead to increased problems with weed resistance. USDA's plant inspection agency has agreed that increased use of the herbicide could hasten the evolution of weeds resistant to it, notes ISU Extension agronomist Clarke McGrath. But USDA said resistance could happen anyway because 2,4-D, sold by Dow AgroSciences and other companies, is the third most-used weed killer in the nation. "I would not have guessed 2,4-D to be that high on the list of herbicides that are most often used," says McGrath.
Dow's Enlist System would be an alternative to the glyphosate system of genetically modified crops, known as Roundup Ready and produced by Monsanto. Increasingly, weeds are becoming resistant to Monsanto's Roundup, a glyphosate herbicide. Roundup Ready crops can have glyphosate applied to them while not damaging the crop, which is grown from genetically modified seed. DuPont Pioneer, the Des Moines-based seed company giant, has a license agreement with Dow to use the Enlist weed control system once it gains regulatory approval.
Would use of Enlist weed control system result in more widespread weed resistance to herbicide?
In a statement, Dow AgroSciences says 86% of corn, soybean and cotton growers in the Southern U.S. already have herbicide-resistant or hard to control weeds on their farms. The number of farmers affected by tough to control weeds in the Midwest has climbed as well, and now tops 61%. "Growers need new tools to control weeds now, to address this weed resistance problem," the company says.
Dow remains optimistic that Enlist corn and soybeans could be on the market by 2015, available for planting by farmers. But Doug Gurian-Sherman, a senior scientist at the Union of Concerned Scientists, says federal approval of Enlist seeds will only increase weed problems resulting from over-use of herbicides. "Because there are no new herbicides in the development pipeline from seed companies, farmers could soon have no good chemical options for weed control, " he says. "So approval of these 2,4-D resistant crops will just make matters worse in terms of widespread weed resistance to herbicides."
Dow agronomists have also worked with grape, fruit and vegetable growers to address concerns about 2,4-D drifting into nearby fields or orchards and harming plants that are more sensitive to the herbicide. Based on that experience, Dow says Enlist herbicide is less likely to float from a field than current 2,4-D products. And the use of Enlist will be restricted—it will be classified as a "restricted use' product and proper guidelines must be followed to use the system.