David Owens, Extension Entomologist, owensd@udel.edu
Corn
Brown stink bugs produce their first generation in small grains, including rye, wheat, and barley. Furthermore, we have seen some unusual green stink bug activity in rye cover crops. Be sure to scout late planted corn in late terminated cover crops for stink bug injury. Also pay attention to corn bordering wheat, especially as harvest draws near. Wheat harvest will drive stink bugs into corn. Stink bugs will concentrate themselves around the developing ear. Thresholds for stink bugs can be found https://corn.ces.ncsu.edu/stink-bug-management-in-corn/. Even if corn is not at a vulnerable stage, a large number of stink bugs confined to the edge can be treated with a border spray before they move deeper into the field.
Soybean
High levels of defoliation were noted in recently planted soybean fields caused by bean leaf beetles and grasshopper nymphs. Defoliation thresholds in vegetative stage soybean are a conservative 40%. As small grains senesce, thrips populations will increase and cause a silvering streaking on leaves. Thrips generally are not associated with yield impact, unless populations are very high and soybean are not growing due to drought.