Got this message from my friend Steve.
This afternoon I spoke with Illinois Natural History Survey Scientist and Aphid Expert, David Voetglin. He told me that there has been a very sharp increase in the abundance of aphids in suction traps placed in east-central Illinois (populations have been high in N. Illinois for some time and the populations have been moving south). He also reported that he was in an Iroquois County field on Monday that had over threshold (threshold is 250 per plant with 80% or more of plants infested) numbers of soybean aphid on every plant. He mentioned the oft-stated wisdom that the hot weather is supposed to slow the aphid reproduction down does not appear to be holding now, it has been hot and the suction trap numbers keep going up so he doesn't know what to expect.I had just visited with a neighbor who was looking at his soybeans and we decided it was too hot for an aphid explosion.