One of the big advantages of genetically modified corn was its built-in pesticides, as it produces a toxin that kills destructive bugs. Now its resistance to pests is wearing off. Just as Jurassic Park taught us, life found a way.
Back in 2003, a strain of genetically modified crop known as Bt corn was introduced. Since the crop produces chemicals that are deadly to the western corn rootworm, one of the most destructive corn parasites, it gave farmers the opportunity to pull in bigger harvests with fewer pesticides. But now, less than a decade later, it seems the insects are already evolving the resistance necessary to keep on eating Bt corn.
The United States has completely embraced Bt corn, and it now accounts for 65% of all corn grown. So far, the rootworms have demonstrated resistance in only a few isolated instances, with the pests destroying crops in parts of four Midwestern states.
A big part of the problem seems to be that farmers aren't taking the same precautions with Bt corn that they used to take with its regular counterpart. Normally, farmers will rotate different types of crops, which lessens the chance that pests can build up a resistance to the protective toxins. But because corn is so ridiculously profitable right now, many farmers are abandoning rotation altogether, thinking that the Bt corn can withstand any pests.
What makes this particularly tricky is that rootworms can destroy crops without us even noticing. The damage inflicted by these pests happens at the roots, but the rest of the corn can still appear healthy and upright unless strong winds or heavy rains arrive to tip them over and reveal the destruction. And, because rootworm ultimately grow up into beetles, they can easily fly from one field to the next, meaning huge areas could suddenly lose their resistance.
Bt corn gets its name from Bacillus thuringiensis, a soil organism whose genes were spliced into the corn. The toxin it creates is harmless for humans and livestock, but deadly to rootworms. Scientists knew this wasn't a permanent solution - sooner or later, the bugs would develop a resistance - but it's happening much sooner than scientists hoped and expected, and we likely need to act now to stop the bugs from fully developing resistance.