First discovered last August, these so-called superbugs (literally) are the western corn rootworms that have developed a resistance to Bt toxin, a bacterium injected into genetically engineered (GE) corn that supposedly kills the worms if they try to eat the corn. Because the corn doesn't contain high enough levels of Bt toxin to kill the worms, they become tolerant to it, in much the same way that bacteria become more virulent when exposed to small amounts of an antibiotic.
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That could lead to some serious financial woes for both farmers and the rest of us, according to a letter sent this week to the Environmental Protection Agency (EPA) by 22 prominent scientists and corn-pest management experts from the U.S. Department of Agriculture and universities across the Midwestern Corn Belt.
Farmers are paying almost double for seeds that don't live up to their promises, and then have to resort to insecticides on top of that, and the result is potential crop failure, which could raise food prices at the grocery store, says Patrick Porter, PhD, associate professor at Texas A&M, who drafted the letter. "It's a societal risk," he says. "If farmers start taking damage to any pest, that will lower yields. That will reduce the supply of corn and increase prices." And, he adds, when prices for corn go up, more farmers start planting corn, despite the risks. "When the price of one crop goes up, growers shift to growing more of that crop, so they grow less of something else, which makes price of that go up. So it's a ripple effect."
In the letter, the scientists wrote that the existence of GE corn-resistant worms was a situation that "should be acted upon carefully, but with a sense of some urgency."
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"Corn rootworm is the most damaging pest to corn in the U.S.," Porter says. There are a few reasons these resistant bugs have managed to outsmart genetically modified crops, the scientists write. First, farmers use the Bt-toxin corn in areas where there isn't a huge corn-rootworm problem, which leads to greater resistance when it's used where there is a problem. And the reason farmers do that, according to the letter, is that they have no other option. "When growers do not want to use Bt corn, many report increasing difficulty in obtaining non-transgenic seed," Porter adds.
Another reason is that farmers aren't following the proper procedure when planting these gene-altered crops. The "best practices" for planting GE seeds involves interspersing rows of the crops with non-GE varieties, which makes it more difficult for bugs and weeds to become resistant. But a survey released in February showed that more than 40 percent of American farmers who planted certain varieties of genetically engineered (GE) corn in 2011 didn't do that.
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"There's a concern that Bt corn has worked so well that the other arrows in the quiver haven't been used as much—things like rotating crops and using insecticides only sparingly," says Steve Pueppke, PhD, associate vice president for research and graduate studies at Michigan State University and one of the letter's signatories.
So the only way farmers have to kill these bugs is to spray more insecticides. One of those, clothiandin, is toxic to honeybees and can remain in soil for up to 19 years. Or they buy more expensive corn varieties that have multiple traits of Bt-toxin resistance, which could kill off monarch butterfly populations. Pollen from Bt-containing corn contains small amounts of bacteria, and those can drift onto milkweed plants, the sole food source for monarch butterflies.
The best way to stand up to the rampant use of genetically engineered corn is to demand organic food at the grocery store, your local co-op, or your farmer's market. Then ask the Food and Drug Administration to require labeling, as over 800,000 people already have by taking part in the Just Label It campaign.