Agronomic Crop Insect Scouting

David Owens, Extension Entomologist,


Scout for stink bugs in corn, especially fields in late terminated small grain cover crop and fields bordering wheat or barley. Between V6 and V14, stink bugs will cause cosmetic injury. However, thresholds are 10 bugs in 100 plants when sampled around the ear-zone from V14 to VT. This threshold almost triples once plants begin silking. You can find more information here:


Thrips feeding is noticeable as silvery streaking on leaves. However, thrips are only rarely associated with any yield impact to soybean and should not require a treatment. We are seeing spider mites begin to move into other crops, begin monitoring for mite hotspots around field edges. Other important defoliators include bean leaf beetle, various worm species, and grasshoppers. However, these are less likely to trigger a defoliation threshold (conservatively set at 30-40% defoliation in full season beans) once the plants have a couple of trifoliates.