A new study from a Michigan State University researcher says one of the nation’s most damaging corn pests is developing resistance to insecticides meant to repel it.
The corn rootworm is a type of beetle that feeds on the roots of corn. The pest can cost farmers across the country up to one billion dollars in damage a year, according to study author Felicia Wu.
A type of genetically modified corn called Bt corn was developed in the 1930s to help eliminate the insect. It contains a natural bacteria harmless to people and animals but poisonous to rootworms and other bugs, she said.
But Wu says overplanting the corn variety means it’s becoming less effective.
“You don’t want to necessarily, for example, put too much of a particular pesticide or particular antibiotic into the environment because that will hasten the process by which the particular insects or the bacteria can evolve resistance to it,” Wu said.
She adds the variety of corn has been abundantly planted in places where it isn’t needed, like the state of Michigan where the rootworm has natural predators.
“The farmers are paying an additional amount for a type of protection they do not need, and overtime ... that introduces more of that particular Bt protein into the environment, and that means that the insects can evolve resistance more quickly,” she said.
Wu is recommending that farmers plant Bt corn only when necessary.