Soybean aphids have been found in a couple of additional areas in the state and it looks like an early start to the race. BUT it’s still a long way from treatable levels (250/plant when aphids are abundant and increasing in a field) and pulling the trigger too early with this insect does not guarantee you won’t have to treat again.

In fact, if populations do develop, it’s a pretty sure thing you will have to retreat. Soybean aphids re-colonize fields and reproduce so rapidly that treating existing populations at the appropriate threshold is the only guarantee of seeing an economic return on your spray investment. So, when it comes time to treat for weeds, don’t assume that throwing some insecticide in the tank will solve your entire season’s aphid problems. It will only show a return if there are treatable populations of aphids in the field at the time of application.

If populations develop later in the season, you’ll likely have to retreat anyway. Another reason to scout and be aware of what aphid populations are doing in your fields…..

Kansas has reported some true armyworms in small grains. Armyworms don’t overwinter in northern MN. Our populations arise from immigrant populations blown in on southerly winds in the late spring and early summer. One of the potential source locations is Kansas. We’ll be watching the light trap in Crookston and if an armyworm flight does show up, it will be reported.

The MDA monitors a system of light traps for armyworm and other night flying moths and reports their weekly catch numbers in the MDA’s Minnesota Pest Report, on the web at:

Ian MacRae
U of MN Extension Entomologist