On May 15-19, 2013, 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
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Aphids in Minnesota
On June 11, 2013, soybean aphids were found on soybeans at the Rosemount Research and Outreach Center near Rosemount, Minn. Not many soybeans were out of the ground there, but in the two fields sampled, entomologists at the University of Minnesota found aphids. They sampled one commercial soybean field at the VC growth stage (unifoliate leaves unfolded) and found 7.5% of plants infested with 1-9 aphids on each infested plant. The other field sampled was a small plot trial, also at the VC growth stage, and had 10% of plants infested with 2-3 aphids on each plant.
This find is in line with what is being seen in neighboring states. Last week, soybean aphids were found on soybean in Wisconsin and northeastern Iowa. It is far too early to be worrying about aphid control; however, you may want to begin checking your fields for aphids, especially when we get into late June.
– Robert Koch, U of M Extension entomologist
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