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Man vs Weeds, Whoever Wins, We Lose: Most scientists try make our lives either better or easier. They’ve cured diseases with antibiotics and killed weeds with herbicides. This was great, until years of overuse made disease-causing bacteria and viruses resistant to antibiotics, and herbicides like Roundup not only caused cancer in humans, but began failing as some weeds became resistant. Stanley Culpepper left his family’s North Carolina farm over 25 years ago to study agronomy in college. “I was trained by some really, really amazing people,” he says, “and I was even trained that there would never be a weed that was resistant to Roundup.” Back then scientists believed that plants couldn’t become immune to Roundup because it required too big of a change in a plant’s biology.
Never say never. In 2005 Culpepper, now with a Ph.D in weed science, reported that he’d found some weeds that Roundup could not kill. They were growing in a field in Georgia — a monster weed called Palmer amaranth, or pigweed. It had become resistant to the main ingredient in Roundup, glyphosate. Since then, it’s spread like a plague across America’s farmland, virtually everywhere in the South and increasingly common in the Midwest. “The impact is just unbelievable,” Culpepper says. “We’ve invested over $1.2 billion, just in the cotton industry, for control of glyphosate-resistant Palmer amaranth since we first discovered it.”
So biotech companies began genetically engineering varieties of soybeans and cotton that can tolerate two other herbicides called dicamba and 2,4-D. Companies had already genetically engineered plants to resist glyphosate. Now farmers could plant these crops and spray the new chemicals right alongside glyphosate to kill their weeds. Problem solved, right? Wrong. Graduate students at Kansas State are spraying the heck out of pigweed with dicamba and 2,4-D and the weeds are loving it. They’re surviving every toxic chemical thrown at them. Can we say the same for the humans doing the spraying?
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