Superweeds Start Herbicide Arms Race on Farms

New breeds of “superweeds” are creeping across the Farm Belt, and shaking up the weedkiller and seed industries in the process. The long-dominant Roundup can't deal with immune invaders like pigweed, horseweed, and Johnsgrass, which has given rival chemical companies a chance to bring back old herbicides that Roundup long ago pushed out of the market, the Wall Street Journal reports.

Roundup took control of the scene by selling both weedkiller and seeds for “Roundup Ready” crops immune to that weedkiller. So now, Dow Chemical, DuPont, and others are spending hundreds of millions to engineer seeds to their older herbicides. “It is a new era,” said one Dow scientist. But the push could be controversial, because those older herbicides are also less environmentally friendly than Roundup; they're more likely to drift to neighboring farms or wild vegetation. (More farming stories.)