This Cousin of Quinoa Could Spell Ruin for American Farms

Palmer amaranth, which can be resistant to herbicides, is showing up in more states.

Palmer amaranth. (Photo: Delaware Agriculture/Flickr)

Jun 23, 2014· 2 MIN READ
Willy Blackmore is TakePart’s Food editor.

When Americans were freaking out about the ethics of eating quinoa last year, a simple question arose: If importing it from Peru and Bolivia is putting the superfood staple out of reach for the people who have farmed it for centuries, then why not just grow it here? It turns out that, in a sense, we already do—but with disastrous consequences. While Americans have yet to intentionally grow much quinoa—we harvested 200 million pounds in 2012—our farmland is proving to be fertile ground for one of the crop’s cousins, Palmer amaranth. The plant has some similarities to quinoa—it’s highly nutritious and was cultivated by Native American tribes—but its tendency to overtake huge swaths of land planted in other crops, such as corn and soybeans, makes it a potential multibillion-dollar threat to the agriculture industry.

Quinoa may be a superfood, but Palmer amaranth is a superweed.

The plant, which can grow up to seven feet tall and seeds very heavily, has been the scourge of Southern farmers for years, but now that it’s showing up in Iowa fields, in the heart of industrial American agriculture, there’s new, growing concern over its spread—and its increased resistance to herbicides. In the past week, both an editorial in the science journal Nature and a story in the Des Moines Register have addressed the problems that the ever more virulent weed is creating, including increased use of older, more toxic herbicides and the reduction in conservation-minded farming practices, such as no-till farming.

It’s unclear if the amaranth growing in Iowa is resistant to the herbicide glyphosate, which Monsanto sells as Roundup and engineers its GMO crops to withstand. But if there’s one thing that the recent coverage of the growing weed problem makes clear, it’s that the dominance of these genetically modified crops and the narrow use of glyphosate to control weeds that their altered genes dictate is not only threatening yields, but also making the American farm a less sustainable, more toxic place.

"If we use one single system, one tool to control a pest, Mother Nature will find a way around that tool," Brent Wilson, a technical services manager at DuPont Pioneer, tells the Register. "That's just the law of nature."

The Nature editorial appears to agree with Wilson’s sentiment, but it’s critical of the biotech industry’s response on the whole. Companies are developing new seeds that aren’t just resistant to glyphosate but to other herbicides as well—the thought being that if a field can be hit with five weed killers without damaging the crop, the better chance there is for a farmer to keep the corn or soy amaranth-free. But that discounts the potential for superweeds that are resistant to more than just Roundup.

“Stacking up tolerance traits may delay the appearance of resistant weeds, but probably not for long,” the Nature piece reads. “Weeds are wily: farmers have already reported some plants that are resistant to more than five herbicides. And with glyphosate-resistant weeds already in many fields, the chances of preventing resistance to another are dropping.”

With herbicides failing them, some farmers are taking the extreme measure of hiring manual labor to weed fields by hand.

While this problem was born on farms that have wholly embraced GMO crops, the 600,000 tiny seeds that one Palmer amaranth plant can throw off don’t really care if they land in an organic field or a conventional one—these superweeds are a threat to the entire $330 billion agriculture industry, from the largest farms down to the smallest.

Nature sees a way to at least stem the tide, albeit in a minor way: By requiring farmers to rotate crops and to rotate herbicides every couple of years, we could make the acres and acres of GMO corn and soy that blanket the Midwest a somewhat less than ideal breeding ground for superweeds like Palmer amaranth.