As our beans start to put on pods, one insect pest that needs watching is stink bugs. There are several species of stink bugs that can be found in soybean, even beneficials. These include the green, the brown, the red shouldered and the brown marmorated stink bug. The spined soldier bug looks similar to the brown stink bug, but has sharper points on its shoulders, and is more brown on the underside (the brown stink bug is actually more green underneath). Both nymphs and adults feed on the developing seed by using their piercing/sucking mouthparts (like soybean aphids) to poke through the pod. Seed that is fed upon will take a flat or shriveled appearance (see picture).
Often this damage is not seen until harvest time, because the pod usually retains its shape, despite the smaller seed. Therefore it is important to scout early and control if necessary. To sample for stink bugs, take multiple 10-sweep samples with a sweep net in multiple locations throughout the field. Average the number of stink bugs in the 10-sweep samples. The threshold to treat is 4 or more stink bugs, adults or nymphs. If soybeans are being grown for seed, the threshold can be dropped to 2 or more stink bugs. If walking, the threshold is 1-2 stink bugs per foot of row. See our soybean insect images page, http://entomology.osu.edu/ag/pageview3.asp?id=1152 , and our provisional stink bug fact sheet (http://oardc.osu.edu/ag/images/StB_Factsheet_June_26.pdf) for more information.