This yield loss can occur in several ways. Pods may be clipped from the plants, or plant diseases may enter the pod through the feeding sites, causing seeds to appear shrunken, discolored, and moldy. This injury reduces seed quality. Beetles injure pods by feeding on the outside layer of the soybean pod, leaving a thin layer of tissue still covering the seed. They very rarely chew through the pod and into the developing seed.
Grasshoppers also feed on pods, but they bite completely through the pod and destroy the seed.
Enlarge Bean leaf beetle injury to a soybean pod. Bean leaf beetle also transmits the soybean pathogen bean pod mottle virus. Tony Weis, Iowa State University Extension crops specialist in Ida Grove, reports virus symptoms on near 100 percent of the plants in infected fields in his area. There is not much that can be done this late in the season to prevent additional losses by this virus. There may be more information to present on this topic at the Integrated Crop Management Conference in Ames this November.