"Attack of the Superweeds"

"Herbicides are losing the war — and agriculture might never be the same again."

"It was already too late for Darren Nicolet to reverse course last June when he heard that the Ninth Circuit Court of Appeals had overturned E.P.A. approval of three products containing dicamba, a controversial but widely used weed killer. A farmer in Kansas, Nicolet had planned his season around the herbicide, planting his fields with soybeans that were genetically modified to survive being showered with the chemical. He was well aware of dicamba’s tendency to vaporize and drift from field to field, causing damage to crops and threatening nearby wildlife and trees, but he didn’t feel as if he had much of a choice: Dicamba was one of the last tools that provided some control over Palmer amaranth, an aggressive weed that would quickly go on to choke out his sorghum crop — and that threatened to overtake his soybeans too. “There was a little bit of a moment of panic there for a few hours,” Nicolet said; he was worried that a season without dicamba would mean devastation for his farm.

If there’s a plant perfectly suited to outcompete the farmers, researchers and chemical companies that collectively define industrial American agriculture, it’s Palmer amaranth. This pigweed (a catchall term that includes some plants in the amaranth family) can re-root itself after being yanked from the ground. It can grow three inches a day. And it has evolved resistance to many of the most common weed killers, continuing to reproduce in what ought to be the worst of circumstances: A three-day-old, herbicide-injured seedling, for example, can expend its last bit of energy to produce seeds before it withers up and dies. Unchecked, Palmer amaranth can suppress soybean yields by nearly 80 percent and corn yields by about 90 percent.

Nicolet was ultimately allowed to spray dicamba last summer because he purchased it before restrictions took effect. He used it this year too: The Trump administration issued new approvals for some formulations containing dicamba just a week before the presidential election. Still, Nicolet says the weed killer will eventually stop working on his land, another management tool rendered useless by the pigweed’s remarkable onslaught. Whether that day is 10 years in the future or three, he has no idea, but the Palmer amaranth continues to gain ground all the while. This summer, a handful of pigweeds sprouted in a field that had recently been sprayed. Nicolet couldn’t weed the 96 affected acres by hand, so he decided to let them grow. “It’s not really enough to hurt yield this year,” he said. “But you know, you have 100 weeds out there, the next year you’ll have a million.”"

H. Claire Brown reports for the New York Times Magazine August 18, 2021.

Source: NYTimes Magazine, 08/20/2021