We released the egg parasitoid Trichogramma ostriniae (Tost) in three sweet corn, five field corn, and three dry bean fields to determine if they could parasitize western bean cutworm (WBC) in the field and if WBC damage was lower where Tost was released. We released at a rate of 90,000 wasps per acre, initiated releases the week after moths were first detected in pheromone traps, and continued weekly releases through the week after peak flight.