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Lisa Behnken, George Haimpel, and Dave Ragsdale

Lisa Behnken, George Haimpel, and Dave Ragsdale are part of a team of Extension educators and researchers working to defeat soybean aphids.

Team Aphid packs a punch

The unbeatable power of University research, education, and teamwork

May 18, 2007

Not every gourmet experience turns out well. One that turned out especially rotten supposedly involved a tourist buying edamame in China, carrying it back to the United States, noticing bugs in the Asian delicacy, and tossing the edamame into trash near Chicago's O'Hare airport. The bugs were soybean aphids, and thus began their spread into Midwest soybean fields.

Only the rapid response from a team of field-based Extension educators, campus Extension specialists, University researchers, growers, crop consultants, and other partners could help reduce the economic and environmental damage from these accidental tourists.

In Minnesota, Lisa Behnken, regional Extension educator, first learned soybean aphids were invading when a southeastern Minnesota farmer came up to her at a July 2001 field day and said, "I think I have that insect you were talking about on the radio." A few days later Extension entomologists Ken Ostlie and Dave Ragsdale and a team of University of Minnesota scientists confirmed the worst.

The situation was bleak. Soybean aphids have voracious appetites and reproduce at rates that put rabbits to shame. One 100-acre soybean field could produce 4.4 billion soybean aphids in a growing season. And in 2001, nobody in Minnesota knew beans about soybean aphids. "It was a very painful birth of a new problem," Behnken said. "Most of the research we had access to was written in Chinese, and some didn't apply to our situation. We had to kick it in high gear fast."

"Our goal is a multitactic approach that combines aphid-resistant plants, natural predators and informed spraying decisions," Ragsdale said.

Team Aphid's first job was to figure out how to kill the darned things. Spraying pesticide was the quick answer, but how much and when? Farmers and crop consultants worked with Extension and other University of Minnesota experts to develop recommendations. By 2002 a sophisticated University of Minnesota computer model combined weather information with agronomic and entomology expertise to guide growers.

Ostlie estimated that in 2002 that model, combined with field scouting and Extension advice, saved growers $200 million in crop losses and reduced pesticide needs. Since then, aphids have spread into new areas and research-based information has become even more important.

The Soybean Aphid Growth Estimator computer simulation that drives the model continues to evolve. Future versions will factor in temperature, rainfall, planting date, plant growth stage, variety, soil type, and natural predators.

"Growers can combine this computer prediction of aphid growth with real-time data observed with field scouting to do the right thing in the field at the right time," Ragsdale said.

Spraying is a short-term fix. Team Aphid's long-term goal: finding a way to enlist nature to destroy the aphids, reducing the need for synthetic pesticides. In addition to interrupting the soybean aphid life cycle, researchers hope to develop soybeans that are less tasty to aphids. "Our goal is a multitactic approach that combines aphid-resistant plants, natural predators and informed spraying decisions," Ragsdale said.

The University of Minnesota soybean aphid response has attracted national recognition. But to Extension educators like Lisa Behnken it is all in a day's work.

"We shine when we pull together and work together as a team of field-based educators, state specialists, and researchers to help producers make better decisions," Behnken said. "That's what we're best at doing."

For more information see soybeans.