Oviposition preference of corn-infesting picture wing flies

Euxesta stigmatias Loew (Diptera: Ulidiidae) has been a serious pest of sweet corn, Zea mays L. in Florida and several Caribbean countries for 80 years. Three additional picture-winged fly species were reared from corn in Florida within the last 2 years including E. eluta Loew, E. annonae (F.) and Chaetopsis massyla (F.). Pest status and oviposition preference of each species was evaluated using undamaged ears and ears previously fed upon by fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) or E. eluta larvae in choice and no-choice trials. All four species oviposited and fed on corn ears as both primary and secondary pests. Euxesta stigmatias produced more pupae than other species and more on S. frugiperda infested ears than other ear treatments. These results will be used along with those of infield distribution studies in progress towards the development of sampling plans and economic thresholds for these flies.