SIU study questions effects of Bt corn

Today's farms are much different from what they were just two decades ago.

Back then genetically modified crops were still in the research and development phase. Now they're a reality, making up huge chunks of the row crops planted in the United States.

At Southern Illinois University in Carbondale, zoologist Matt Whiles is part of a team taking a hard look at one type of genetically modified crop, Bt corn, and its effects on the environment, with a National Science Foundation grant. Last week, the group -- including researchers from Indiana University, the University of Notre Dame and Loyola Chicago University -- published a study that said, at least preliminarily, that Bt corn might be harming freshwater ecosystems.

The paper was published in the Proceedings of the National Academy of Sciences.

"What this paper shows is that there may be some effects that have not been considered closely yet, so we don't know the extent of those effects," Whiles said. "This paper should not sound off a bunch of alarms. ... It is somewhat preliminary in nature."

Researchers say Bt. corn may be slowing the growth of caddis flies.

Few studies have looked at the effects of using genetically modified crops on freshwater ecosystems in agricultural areas, Whiles said.

The Bt corn studied is genetically modified to be resistant to the European corn borer, a destructive moth larva. When they attack crops, the insects can do damage and decrease yield and grain quality. The study showed evidence that, when the remnants of the Bt corn enter water supplies, it may slow the growth of caddis flies, an insect important to freshwater environments.

Bt corn is widely used. Gary Clark, director of market development with the Missouri Corn Growers Association, estimates about 70 percent of U.S. corn has some form of Bt in it, the toxin genetically engineered into corn to kill pests like corn borers.

Yields improving

The modified corn has seen a dramatic increase in use in the past few years, Clark said, and it works.

"Producers are seeing the average consistency of their yields getting better," Clark said.

Clark recently went to China with the U.S. Grains Council to assess corn yields there, and said the lack of Bt in the corn there was evident.

"It was like setting back the clock 10 to 15 years here," Clark said.

Bt corn has been approved for human consumption by health authorities, but it also falls under EPA regulation because of its environmental ramifications, since it kills corn borers.

"EPA will thoroughly review the study, and will determine whether the information warrants further regulatory action. In registering Bt corn, EPA required and reviewed numerous studies to ensure that Bt corn products meet current health and environmental standards. EPA's evaluation process is based on the best available science and data, and includes peer review. EPA will publish a response to the study once the information has been fully considered," the agency said in a prepared statement.

Whiles said more research needs to be done to either validate or disprove the study's findings.

But if Bt corn does harm a fragile ecosystem and was taken off the market -- both hypotheticals at this point -- Clark said it would have a major economic impact.

But Clark said the ag industry isn't anti-environment, and more studies need to be done to see if indeed genetically engineered crops are harming the environment.

msanders@semissourian.com

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