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December 15, 2012

'superbugs'

New breed threaten nation's crops

(Continued)

And it worked. The U.S. Department of Agriculture reported that per-acre use of pesticides on corn, soybeans and cotton declined by several million pounds per year, and soil tillage declined, as well.

But the genetic breakthroughs brought sweeping changes across the landscape. Today, much of the Midwest is planted with just two genetically modified species — corn and soybeans.

In short, Midwestern agriculture quickly evolved into a vast, efficient system that is much easier to farm but is “biologically simple,” said Doug Gurian-Sherman, a senior scientist with the Union of Concerned Scientists, and a specialist on biotech agriculture.

“The problem is,” he added, “it’s a perfect storm for resistance.”

Adaptation is as old as evolution itself. First, the few weeds or bugs that just happen to be immune to the pesticide survive. Then, in a biologically simple environment devoid of competition or threats, they flourish. Farmers encountered pesticide resistance many times before Roundup and genetically modified crops came along.

But the revolution in agriculture has become a victim of its own success.

In recent years, scientists have identified an estimated 23 weeds around the world that no longer die when doused with Roundup. Many are the most prolific and two, giant ragweed and water hemp, are a bane to farmers. “The scale of it is really dramatically different,” said Gurian-Sherman.

More recently, infestations of rootworm, known as the $1 billion insect because of its cost to farmers, have exploded.

The next generation of genetically modified seeds, designed to combat the new resistant pests, will work for a while, skeptics concede. But eventually, they say, nature will evolve again.

“My jaded, cynical perception is that it indicates a learning disability on the part of everyone,” said Bruce Potter, an assistant professor of entomology at the University of Minnesota.

There is another solution, says Potter, but one that can work against the economic interests of farmers and pesticide companies: Plant something else for a while. Alternating corn and soybeans, and mixing in other crops from season to season, can improve the soil and defeat the bugs and weeds.

It’s a lesson in leveraging biological diversity that Serfling saw with his own eyes. This summer he had to hire a helicopter to spray insecticide on his bug-infested corn. But across the driveway, another field stood tall in the wind. The difference: The previous year, he’d planted alfalfa.

“Rotate. That’s how you get rid of it,” he said. “Rotate, rotate, rotate.”

Distributed by Scripps Howard News Service, www.shns.com.

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