Comparative lab and field biology of three picture-winged fly pests of corn

Several picture-wing fly species (Euxesta and Chaetopsis spp.) (Diptera: Ulidiidae) are serious pests of corn, Zea mays L., in tropical and subtropical America. Egg, larval and pupal development periods for the three most common species attacking corn in Florida were compared in the lab on corn earworm diet and in the field within corn ears. Adults of each species reared from each larval food source were used to determine longevity, pre- and post-oviposition periods, as well as daily and overall ovipositional patterns. Mean development times varied significantly among species for each stage with no one species having the quickest times for all three stages. Total developmental period followed the pattern of Euxesta stigmatias Loew > Chaetopsis massyla (Walker) > Euxesta eluta Loew and was longer for all the species in corn than in diet. Larval periods were longer for all the species raised on corn ears than on diet while pupal periods were longer for those from diet than from ears. Adult longevity followed the pattern of E. eluta > E. stigmatias > C. massyla. These results along with those from in-field fly distribution studies will be used to design better fly management strategies for corn production.