UNL has been tracking an unusual insect pest the past couple of years in northeast Nebraska that may be a potential concern to farmers growing corn after rye or other grass cover crops. A number of producers and crop scouts have reported stunted corn plants at V1 to V2 with brown flagging in their fields due to the wheat stem maggot (WSM), a species of Chloropid fly. These are small flies that are typically about 1/8 inch long with black and yellow markings. The wheat stem maggot overwinters in the stem of its host plants as a larva and emerges in May to begin feeding.