The days of soybean aphids feasting on Minnesota's soybean fields may be numbered.

University of Minnesota scientists are field testing a beneficial insect--a stingless wasp also known as Binodoxys communis--that kills soybean aphids. The U received permission from the federal government to proceed with the research and is the leading institution in the testing.

A successful field test would be a major breakthrough in controlling a damaging Minnesota crop pest. The soybean aphid appeared in Minnesota fields in 2000 and today costs Minnesota soybean growers an estimated $200 million annually in lost crop yields and spraying costs.

"The soybean aphid was imported without any of its natural enemies, the organisms that keeps aphids in check in China," said Dave Ragsdale, a University of Minnesota entomologist. "Our researchers and Extension experts are working to provide that check-and-balance system in Minnesota."

Multiple stages of evaluation and testing have been completed at the Insect Quarantine Facility, a joint effort between the Minnesota Department of Agriculture and the Minnesota Agricultural Experiment Station on the U's Twin Cities campus in St. Paul. Special security and air filtration systems ensure that the insects being evaluated don't venture out on their own. Field testing will take place in a limited number of grower fields and at Research and Outreach Centers.

Binodoxys communis was approved for release based upon four years of laboratory safety testing. It is an especially promising species for control of soybean aphid because it comes from a region in China that is a good climate match to Minnesota. The stingless wasp specializes in soybean aphid and has been observed apparently controlling it in China.

A cooperative effort between the University, the state, and soybean growers have made this experiment possible.

"The soybean check-off (a farmer financed fund to research and promote the crop) is committed to supporting research that will mitigate this devastating pest," said Larry Muff, farmer and co-chair of the Minnesota Soybean Research and Tech Transfer Committee. "Organic growers will also benefit from this biological control of aphids."

University researchers and Minnesota Department of Agriculture scientists will monitor the ability of Binodoxys communis to kill soybean aphids this summer and continue the attack this fall when soybean aphids move to buckthorn plants. And the researchers will test to see whether Binodoxys communis will survive the winter to battle soybean aphids in 2008.

There's also a backup plan. Eleven other species and strains of stingless wasps are under evaluation and some of these that have shown promise from both a safety and efficacy standpoint may be field tested in 2008.

More information on the field testing is available at:

http://www.soybeans.umn.edu/crop/insects/aphid/aphid.htm