Reports from my colleagues around the Midwest indicate that soybean aphids are hatching on buckthorn. Bob O'Neil, Purdue University, is working with aphids in Illinois and noted the first hatch occurred on March 27. Chris DiFonzo, Michigan State University, found newly-hatched aphids in central Michigan on April 17. To the west of us, Tom Hunt, University of Nebraska, found soybean aphids on buckthorn in Lincoln on April 23.
Dave Voegtlin, Illinois Natural History Survey, notes that soybean aphids can produce up to four generations on buckthorn in the spring, with winged females from each generation flying off in search of soybean. Therefore, we can expect winged female aphids to be moving from buckthorn and actively searching for soybean plants during May.
This article originally appeared on page 31 of the IC-492 (6) -- May 3, 2004 issue.