On May 15-19, 2013, Drs. David Voegtlin (retired entomologist, Illinois Natural History Survey) and Dave Hogg (Professor, University of Wisconsin, Madison), surveyed the overwintering hosts of soybean aphids — the common buckthorn (Rhamnus cathartica) and glossy buckthorn (Frangula alnus). Their 2,000 + mile survey of these primary hosts took them across Illinois, Indiana, Michigan, Minnesota, Ohio, South Dakota, and Wisconsin. A synopsis of their observations by state are provided below.
- Illinois -aphid colonies found in Mississippi Palisades State Park, Savannah, Illinois; Quad Cities – surveyed three sites, aphids numerous at one location, present at two remaining sites; Joliet – discovered some small colonies, overall aphids not numerous
- Indiana – aphid colonies easy to find near LaPorte and Rome City
- Michigan – aphids discovered near Augusta, not numerous
- Minnesota (western) – no aphids found
- Ohio – aphids were abundant near Toledo (Secor Park)
- South Dakota – no aphids found
- Wisconsin – aphids found near Prairie du Chien
The entomologists concluded that aphids were more abundant on this expedition than the exceptionally early spring of 2012. They did add a cautionary statement regarding the identification of the aphids that were collected, that is, some of the aphids observed could be a different aphid species — A. nasturtii (buckthorn aphids).
On June 4, Dave Hogg observed soybean aphids on seedling soybeans (VC – V1) at a research farm near Madison, Wisconsin. They sampled 100 plants and discovered that 13 were infested with aphids. It’s too early to tell what type of season producers should expect from this insect pest. Mild summers tend to promote greater soybean aphid activity and injury to soybeans. Hot and dry summers tend to work against the establishment of soybean aphids. I offer my thanks to David Voegtlin and Dave Hogg for sharing these early-season observations.