Stink bugs: Stink bugs commonly encountered in soybean: green stink bug, Acrosternum hilare [adult and nymph, first two from left], brown stink bug, Euschistus servus [adult and nymph, 3rd and 4th from left, respectively], spined soldier bug, Podisus maculoventris [adult, last one from the left]. Not to scale. (Photos Marlin E. Rice)
Brown marmorated stink bug: Brown marmorated stink bug is a new pest with unknown damage potential to soybean. Adults are speckled brown with white antennal bands. Nymphs are dark brown with white bands on the legs and antennae. (Photos by Natasha Wright and David R. Lance)
Stink bug eggs: Stink bug eggs on a soybean leaf collected in early September, 2004. Probably from the green stink bug Acrosternum hilare. (Photo Marlin E. Rice)
There are several species of stink bug found in soybean in the northcentral United States. One of our species is green, the green stink bug, Acrosternum hilare). However, we have several species which are brown; the brown and dusky stink bugs, Echistus spp., and spined soldier bug, Podisus maculiventris (Panizzi, A. R., J. E. McPherson, D. G. James, M. Javahery, and R. M. McPherson, chapter 13 "Stink Bugs (Pentatomidae)" In Schaefer and Panizzi, 2000). There is also a new, invasive stink bug called the brown marmorated stink bug (Halyomorpha halys. It was first detected in Iowa in 2011 and the distribution and damage potential to soybean is not fully understood.
The "brown species" of stink bugs differ in that the spined soldier bug has very sharp spines that project from its "shoulders", black markings around the abdomen near the wing margins, and a well-developed spine on its abdomen. Most Echistus spp. have dull "shoulders" (relative to the spined soldier bug), no bands on the abdomen, and no spine on its abdomen. The brown marmorated stink bug is relatively large to other brown-colored stink bugs, with a dark speckled body, white bands on the antennae, and rounded shoulders. These differences are important because the spined soldier bug is a beneficial insect whereas the brown, brown marmorated, and dusky stink bugs will feed on soybean.
The nymphs of the green stink bug are easily distinguish from the others by black bands on its abdomen and orange markings near the head and on the abdomen. The brown, brown marmorated, and dusky stink bugs have sparse brown markings.
The eggs are small and white when first laid (they darken as the bug develops inside). Stink bugs lay there eggs in clusters glued the the surface of the soybean leaf.