Corn Pest Decline Possibly Due to Genetically Modified Plant

The European corn borer is a major pest when it comes to crops. Now, though, researchers have revealed that populations of this insect have declined significantly in the eastern United States. Not only that, but this decline could be partly blamed on the use of genetically modified corn that's resistant to the European corn borer (ECB).

"ECB, which was introduced to North America from Europe in the 1900s, used to be the most important pest of corn in the United States," said John Tooker, one of the researchers, in a news release. "Not that long ago, it caused crop losses that annually approached $1 billion nationwide, and $35 million in the northeastern United States."

In order to combat the corn borer, many farmers turned to genetically modified corn. This corn was created to produce insecticidal toxins that can kill the worms. The toxin itself can be found in the bacterium Bacillus thuringiensis (Bt), which naturally occurs in soils. When the corn borer ate this modified corn, it ended up dying instead of reproducing.

In order to examine current ECB populations in Pennsylvania field corn, the researchers assessed larval damage in Bt and non-Bt corn hybrids at 29 sites over three years. They also planted Bt and non-Bt corn hybrids on farm sites across four growing zones. They then assessed corn borer damage on 400 random plants at each site.

"Our results confirm that we are seeing widespread population declines of ECB in the East, similar to declines that have been found in the Midwestern United States," said Eric Bohnenblust, one of the researchers, in a news release. "With less ECB damage around, non-Bt hybrids in our tests yielded just as well as Bt hybrids, so the decline in ECB populations provides an opportunity for growers to generate greater profits by planting high-yielding non-Bt seed, which is much cheaper than Bt seed. Secondarily, planting more non-Bt corn will reduce the potential for ECB to develop resistance to Bt toxins as corn rootworms have done in about a dozen states so far."

The findings reveal how genetically modified corn can make a difference when it comes to deterring pests. More importantly, though, it shows that farmers may be able to earn more by switching over to regular corn seed. This could have huge implications for the future.

The findings are published in the journal Pest Management Science.