Serious webworm damage in alfalfa was reported from a dozen widely scattered counties south of Interstate 80 during the first 2 weeks of August. I have found larvae but no economic damage in the Ames area. Each summer, this insect is fairly common in Iowa alfalfa, but economic damage in alfalfa is extremely rare, with this year being the exception.
Iowa State University
Rice, Marlin E., "Webworms hammer alfalfa, and also hit soybean" (2001). Integrated Crop Management News. 2006.
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