Posted: 10.08.2010

New facts released show biotechnology benefits more then just the farmer
using it.

A multistate team of scientists has published a new report that
shows genetically modified Bt corn throughout the Upper Midwest
has suppressed populations of the European corn borer, a major
insect pest of corn, with the majority of the economic benefits
going to growers who do not plant Bt corn.

In Wisconsin, 75 percent of the $325 million cumulative economic  
benefit linked to Bt corn's pest suppression between 1996-2009 went to  
non-Bt corn growers. Wisconsin currently has about 3.9 million corn  
acres, with approximately half in Bt corn.

"This study is the first to estimate the value of area-wide pest  
suppression from transgenic crops and the subsequent benefit to  
growers of non-transgenic crops. In this case, the value of the  
indirect yield benefits for non-Bt corn acres exceeded the net value  
of direct benefits to Bt corn acres," says co-author Paul Mitchell, a  
University of Wisconsin-Madison agricultural economist who conducted  
the economic analysis for the study.

Bt corn is genetically modified (GM) to contain a protein from the  
soil bacterium Bacillus thuringiensis (Bt) that kills insect pests.  
According to the team's calculations, the total economic benefit of Bt  
corn's pest suppression across Wisconsin, Minnesota, Illinois, Iowa  
and Nebraska between 1996-2009 adds up to about $6.9 billion. When the  
team broke the numbers out by Bt and non-Bt fields, they were  
initially surprised to find that 62 percent of Bt corn's economic  
benefit - about $4.3 billion - went to non-Bt corn fields.

On second thought, however, the finding made sense. The primary  
benefit of Bt corn comes in the form of reduced yield losses, a  
benefit that Bt corn growers pay for in the form of Bt technology  
fees. As a result of Bt corn's area-wide pest suppression, however,  
growers who plant non-Bt corn in their fields also experience yield  
savings without the cost of Bt technology fees, and thus receive more  
than half of the benefits from growing Bt corn in the region.

European corn borer moths cannot distinguish between Bt and non-Bt  
corn, so females lay eggs in both kinds of fields, explains University  
of Minnesota entomologist William Hutchison, the study's chief author.  
Once eggs hatch in Bt corn, young borer larvae feed and die within 24  
to 48 hours.

Because it is effective at controlling corn borers and other pests, Bt  
corn has been adopted on about 63 percent of all U.S. corn acres. As a  
result, corn borer numbers have also declined in neighboring non-Bt  
fields by 28 percent to 73 percent in Minnesota, Illinois and  
Wisconsin, depending on historical pest abundance and the level of Bt- 
corn adoption. 

This is the first study to show a direct association between Bt corn
use and an area-wide reduction in corn borer abundance.

The authors say there are probably other benefits they didn't measure - like 
a decrease in insecticide use.

Finally, the authors emphasize that sustaining the economic and  
environmental benefits of Bt corn and other transgenic crops for  
adopters and non-adopters alike depends on the continued stewardship  
of these technologies. Farmers, industry and regulators need to remain  
committed to planting non-Bt corn refuges to minimize the risk that  
corn borers will develop resistance to Bt corn. The Science study  
shows that Bt corn is more valuable to society than originally  
realized, which makes maintaining its effectiveness even more important.

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