The summer of 2005 saw an increase in soybean aphid populations from very low populations experienced in 2004. Although not completely unexpected, the differences between 2004 and 2005 are still remarkable. Last year, many field crop entomologists were at a loss for data, with soybean aphid populations peaking at no more than a couple hundred per plant. This year we collected plenty of data, with long days spent counting sometimes thousands per plant. The record for aphid outbreaks was set in Michigan. Chris DiFonzo, field crop entomologist at Michigan State University, reported nearly 90 percent of the soybeans planted in the state were treated for soybean aphids. In the Lower Peninsula, populations went well above our current recommended threshold (250 per plant) in June and reports of spraying continued into August.
O'Neal, Matt, "Insecticide use for soybean aphid control up again in 2005" (2005). Integrated Crop Management News. 2409.
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