David Owens, Extension Entomologist, owensd@udel.edu
Soybean
The usual defoliator complex is active now, including Japanese beetle. I found my first one in Laurel this week. Bean leaf beetle feeding is evident, along with bean leaf roller folding leaves under. With recent cool, cloudy, and wet weather, be sure to check for possible stand loss from slug activity resurgence, particularly in high-residue cover cropped fields where no row cleaners or vertical or turbo tillage was done.
Corn
Now that small grains are being harvested, any stink bugs that have been developing on the grain are going to move elsewhere. Now is an excellent time to check edges of corn/wheat fields for stink bug. Stink bugs will often move to the edge of fields and stay there for a period of time before dispersing into the field interior. If an above threshold population is building up on the edge, a border spray may be all that is needed to protect the corn. Also scout pivot tracks, as the opening in the field acts like an insect highway.
Alfalfa
Continue scouting for potato leafhopper. Once yellowing is observed, damage has already been done. While scouting for leafhopper, note any blister beetles. If selling hay as horse feed, you may want to think about an insecticide before harvest to knock them down.