Nelson's struggle to control crop-choking weeds is being repeated all over America's farmland. An estimated 11 million acres are infested with "super weeds," some of which grow several inches in a day and defy even multiple dousings of the world's top-selling herbicide, Roundup, whose active ingredient is glyphosate.
The problem's gradual emergence has masked its growing menace. Now, however, it is becoming too big to ignore. The super weeds boost costs and cut crop yields for U.S. farmers starting their fall harvest this month. And their use of more herbicides to fight the weeds is sparking environmental concerns.
"Most of the public doesn't know because the industry is calling the shots on how this should be spun," Mortensen said, professor of weed and applied plant ecology at Penn State University, who has been helping lobby members of Congress about the implications of weed resistance.
At the heart of the matter is Monsanto Co, the world's biggest seed company and the maker of Roundup. Monsanto has made billions of dollars and revolutionized row crop agriculture through sales of Roundup and "Roundup Ready" crops genetically modified to tolerate treatment with Roundup.
But the system has also encouraged farmers to alter time-honored crop rotation practices and the mix of herbicides that previously had kept weeds in check.