David Owens, Extension Entomologist; owensd@udel.edu
Soybeans
Continue to check fields for defoliation. The defoliator complex is present, generally at populations that do not require treatment. Insects include bean leaf beetle, bean leafroller, green cloverworm, thrips, and Japanese beetle.
Field Corn
Some of our earliest fields are silking, and Japanese beetle are flying. Generally, Japanese beetles are an ‘edge’ species, present around field edges and pivot tracks. If you see large numbers, a good rule of thumb is ½ inch of silk or less, less than 50% pollination, and 2 or more Japanese beetles per ear.
There has also been some concern in the area regarding stink bugs. Dominic Reisig at NC State has a very useful fact sheet explaining a dynamic stink bug threshold for young corn and corn that is beginning to form ears. It can be found here: https://entomology.ces.ncsu.edu/2018/04/new-stink-bug-thresholds-in-corn/.