Finding soybean aphids on buckthorn

Soybean aphids overwinter as eggs on buckthorn and typically hatch right around bud burst. There are several wingless generations on buckthorn before they migrate to soybean each year. Every spring, Dr. Dave Voegtlin (University of Illinois) tours around the midwest looking for soybean aphids on buckthorn. The suction trapping network collected very few aphids last summer and fall, and so he wasn't expecting to find many aphids during his inspections.

General locations he visits every year include Rome City area in N.E. Indiana, Toledo area, Irish Hills in S. E. Michigan, Kellogg Forest near Battle Creek, Michigan, Calumet area S. of Chicago, Joliet, IL and Quad Cities area.  All these have abundant buckthorn available for overwintering. He found active aphid colonies at about half of these locations. He was surprised to see aphids because of the cool weather in the midwest so far. This is one of his pictures from a couple years ago, showing a spring colony on buckthorn being tended by aphids.

It won't be long before migratory aphids are moving to soybean. Even though it was an extremely low aphid year in 2010, we don't know what will happen this year if conditions are conducive to their growth potential. I'll keep you posted as regional information is shared.