Funding from the North Central Soybean Research Program and the North Central Integrated Pest Management (IPM) Center allowed the soybean entomology lab at Iowa State to establish four soybean aphid suction traps during the 2005 growing season. The traps are designed to capture soybean aphids as they migrate to new soybean fields or back to buckthorn, their overwintering host. The traps are composed of a 20-foot vertical tube with an electric fan at the base. The fan pulls air through the tube and deposits aphids into an alcohol-filled jar. The jar is replaced every week and the contents are sent to David Voegtlin at the Illinois Natural History Survey.
Voegtlin is an aphid taxonomist and the coordinator of this multi-state suction trap network. Each week, from May through October, Voegtlin and his crew sort through the contents of 20+ traps located across the North Central region. Not only does he count the number of soybean aphids per trap and determine their sexual morphology, he also identifies potentially hundreds of aphid species collected within these traps. To draw inferences regarding the potential overwintering success of soybean aphids, Voegtlin will determine the number of winged males and females collected each week. It is these sexually reproducing males and females that produce eggs that overwinter on buckthorn.
Based on their density, we can make some predictions about the likely overwintering success of soybean aphids from year to year. We will keep you informed of the suction traps' progress as these estimates come in. To see the current results and location of each trap, visit the trapping website .
This article originally appeared on page 189 of the IC-494(23) -- September 19, 2005 issue.