By Carey Gillam
(Reuters) - The U.S. Department of Agriculture on Wednesday gave final approval to new genetically modified corn and soybeans developed by Dow AgroSciences that, while heavily criticized by environmentalists and some farmers, are portrayed by Dow as an answer to weed resistance problems that limit crop production.
Approval of the specialty corn and soybeans to be sold as part of a branded "Enlist Weed Control System" means the traits could be on the market for the 2015 U.S. planting season, according to Dow AgroSciences, a unit of Dow Chemical.
Dow is still awaiting approval from the Environmental Protection Agency for Enlist herbicide, which the genetically altered Enlist corn and beans are designed to tolerate.
Like the popular Roundup Ready system developed by rival Monsanto Co., farmers who plant Enlist crops can spray their fields with Enlist herbicide and kill weeds but not the crops.
Corn and soybeans containing Monsanto's Roundup Ready trait, which can tolerate sprayings of Roundup herbicide, make up roughly 90 percent of U.S. corn and soybean plantings every spring.
But heavy use of Roundup has triggered an explosion of herbicide-resistant "super weeds" that are hard for farmers to fight and which can choke off crop yields.
The prevalence of resistant weeds has more than doubled since 2009 and so-called "super weeds" now infest roughly 70 million acres of U.S. farmland, according to Dow.
Because weeds have not yet developed resistance to Enlist, the system addresses the problem.
“Enlist will help farmers increase their productivity to meet the growing demand for a safe and affordable food supply,” Tim Hassinger, president of Dow AgroSciences, said in a statement.
Dow pegs the market opportunity for Enlist at about $1 billion.
Monsanto is also developing a new biotech cropping system.
Enlist combines a 60-year-old herbicide component known as 2,4-D with glyphosate, the chief ingredient in long-used Roundup.
Opponents say the use of 2,4-D can cause potential health and environmental problems, including increasing weed resistance. And they fear the chemical will damage neighboring farm fields. Fruit and vegetable farmers are particularly concerned that 2,4-D drift will lead to crop damage. But Dow has said the Enlist system is safe if properly used.
"The USDA approval of Enlist after such a fundamentally flawed review process is a slap in the face to farmers," said Marcia Ishii-Eiteman, senior scientist with Pesticide Action Network (PAN). "Thousands of farmers have warned USDA of the crop damage, economic losses and health risks they will face from pesticide drift, if these 2,4-D resistant seeds hit the market."
Ishii-Eiteman hinted at a lawsuit, saying PAN would pursue "legal options" to protect farmers.
(Reporting by Carey Gillam in Kansas City; Editing by Cynthia Osterman)