No. 7 Article 1/May 6, 2005

Soybean Alatoid Nymphs Reported on Buckthorn Plants on Purdue Campus

Just recently, Bob O'Neil, an entomologist at Purdue University, reported finding alatoid soybean aphid nymphs (aphids with "wing pads") near the campus in West Lafayette. This means that fully winged soybean aphids will soon begin their search for soybean plants. This search will prove futile for many weeks, and mortality of these winged aphids may be quite high. In some cases, winged aphids may return to their overwintering buckthorn host and begin a new generation of aphids.

At present, we really don't know as much as we would like regarding this asynchrony between soybean development (or lack thereof this spring) and winged aphids leaving buckthorn in the spring. David Voegtlin, an entomologist with the Illinois Natural History Survey, and Bob O'Neil surveyed several locations in Illinois (April 19-21) this spring and found pockets of overwintering soybean aphids on buckthorn in Champaign and McHenry counties, in the Quad Cities, and near Rockford. These observations correlate with the large flights of soybean aphids leaving soybean fields late last summer enroute to their overwintering host.

Because many soybean fields have yet to be planted, many soybean aphids in search of soybean plants this spring may reach a dead end. However, if many return to buckthorn and begin some new generations, perhaps we will have plenty of soybean aphids to contend with this growing season. Although we have learned a great deal about this new invasive insect species in the past several growing seasons, we have much more to learn.

David Voegtlin is coordinating a multistate soybean aphid monitoring project that will begin this summer. Cooperators in 11 states will use large suction traps to monitor soybean aphid flights throughout the summer: Illinois (9 suction traps), Iowa (4), Indiana (6), Kansas (1), Kentucky (1), Michigan (3), Minnesota (4), Missouri (1), Nebraska (1), Virginia (1), and Wisconsin (5). David and his students will be busy this summer keeping track of the samples being sent from each of the cooperating states. By conducting this project for many years, we will begin to improve our understanding of the population dynamics of this important insect pest of soybeans.--Mike Gray

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