Corn in central Iowa.

A study finds an early tool of genetic engineering in crops shows benefits beyond its original intent.

So-called BT seeds are engineered with genetics from soil bacteria that kill specific insects. Researchers now say BT seeds provide additional environmental benefits. Steve Naranjo, with the U.S.D.A. Agricultural Research Service, is one of the paper’s authors. Naranjo says, “Because we can now control certain major pest insects in the crop through this gene being expressed in the plant, that eliminates largely the need to spray insecticides to do the same job.”

Naranjo cautions that insects are adaptable and can develop resistance to even the best tools, so he suggests farmers use technology alongside crop rotation and other strategies. Iowa State University entomologist Erin Hodgson, who was not involved with the study, says BT has been fairly successful in corn.

“Eventually, over time, I think the insects will win,” Hodgson says. “So, in some cases like corn borer, it’s worked really well. In other cases like corn rootworm, it hasn’t held up as strongly.” The review of hundreds of studies shows BT seeds offer protection even to adjoining fields where the seeds haven’t been planted. Globally, BT crops have been grown on more than one-billion acres.

(Thanks to Iowa Public Radio’s Amy Mayer)