INVESTING CHECKOFF DOLLARS
Adam Bierbaum , farmer from Griswold
GALL MIDGE WAR CONTINUES R E S E A R C H O N G O I N G TO D E T E R M I N E T R E AT M E N T O P T I O N S BY BETHANY BARATTA
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owa Soybean Association (ISA) member Adam Bierbaum and his dad Brent suspected a problem in their soybean fields in early July last year. “We started seeing soybeans die on the edge of the soybean fields,” Adam says. “On the outside borders of the fields were strips of wilted soybean plants.” They didn’t know how bad the problem was until they consulted with a variety of agronomists searching for answers. The Griswold farmers called agronomists at Iowa State University (ISU), which ruled out herbicide injury and sudden death syndrome. Splitting open stems, ISU agronomists confirmed the plant injury was the result of soybean gall midge. “It was a pest we never heard of
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before, so that was something new for us,” Adam says. “It was easier to spot damage when we knew what we were looking for.” The pest ate its way about 60 feet into the field and took out half the yield of that entire field. This year, the war on soybean gall midge continues in the state and on the Bierbaum farm. Confirmations of soybean gall midge were reported in 2011 from Nebraska and in 2015 from South Dakota. In 2016 and 2017, there were isolated reports of soybean injury by soybean gall midge in northwest Iowa. There was significant field edge injury and economic loss in at least 65 counties throughout Iowa, Nebraska, Minnesota and South Dakota last year.
Since finding the pest in Iowa fields, not much is yet known on the life cycle of the pest or how to control its emergence and spread. “Despite everybody’s efforts to come up with a strategy to control them, there doesn’t seem to be a silver bullet yet,” says Drew Clemmensen, regional agronomist for ISA. Clemmensen has been working with farmers in western Iowa, an apparent hot spot for soybean gall midge infestations.
Tricky pest Soybean gall midge adults are identifiable by their distinct black and white banding pattern around their legs. But it’s the larvae that are doing damage inside the soybean plant stem. Soybean gall midge larvae are clear
