Growing More Corn for Ethanol Makes Pest Control Harder
By Henry Fountain, The New York Times, December 22, 2008
As American farmers have grown more corn for ethanol production, concerns about the practice have increased, too. Critics say turning more acreage over to corn to make fuel can lead to higher prices for other crops, increased soil erosion and other negative effects.
The less diverse the crops, the fewer insects like this Asian lady beetle to destroy soybean aphids. (Kurt Stepnitz)
Here’s another potential problem: biological pest control.
In a report in The Proceedings of the National Academy of Sciences, Douglas A. Landis ofMichigan State University and colleagues show that increasing the corn acreage can reduce the abundance of insect predators that control aphids, the most significant soybean pest in the United States.
An earlier study by the researchers of fields in Iowa, Michigan, Minnesota and Wisconsin showed that landscape diversity around a soybean field had a great impact on the abundance of beetles and other insects that help to control aphids. With more nearby fields being turned over to corn, that diversity decreases.
The earlier study also quantified the effect of these insect predators. Using those data, the researchers calculated the impact of the shift in corn production — acreage increased up to 20 percent in the four states from 2006 to 2007 — on soybean crops.
They estimate that in the four states, the cost to soybean producers in lower yields and increased need for pesticidesis nearly $60 million a year.
Posts
No comments:
Post a Comment