Hot weather isn't favorable for soybean aphid, so numbers are still down. But spider mites and other pests thrive in these conditions.
Soybean aphid populations remain low but first generation bean leaf beetles are out i some areas this week. Spider mites are still the primary problem, and we encourage scouting to protect yield.
Most of the state is approaching the seed fill stage (R5), indicating the end of profitable yield returns with an insecticide application. Watch a short video about spider mite management here: http://bit.ly/NdDj6c
The 2013 season of podcasts begins with a short recap of pest activity in Iowa.
This week, Erin Hodgson talks about confirming soybean aphid in Iowa, Minnesota, Michigan and Wisconsin.
Matt and Erin recap a presentation made at ICM Conference this week. Bob Koch (University of Minnesota) talked about bifenthrin failures to soybean aphid in southern Minnesota in 2015. He performed bioassays and detected resistance. The level of resistance was low, but provides the first example of this pest overcoming a pyrethroid in the field. Bob's ICM proceedings article summarizes highlights how resistance happens and strategies for prolonging insecticide efficacy. Find the proceedings free here: https://store.extension.iastate.edu/ (search for publication AEP 0302 - 2015, pages 75-76).