Parasitoids attacking fall armyworm (Lepidoptera: Noctuidae) in sweet corn habitats

Abstract

Fall armyworm larvae, Spodoptera frugiperda (J. E. Smith), were collected from sweet corn plants (Zea mays L.) in fields located in three south Florida counties. Fields were sampled from 2010 to 2015 during the fall and spring seasons. Larvae were transferred to the laboratory to complete development. The objective of the study was to identify the common parasitoids emerging from larvae that are present in sweet corn habitats where insecticides are traditionally used. A total of 8353 fall armyworm larvae were collected, of which 60.6% (5062) developed into moths after feeding on corn tissue and artificial diet. Parasitoids emerged from 2365 larvae (28.3%), and parasitism ranged from 1% to 91.7%, depending on site. Parasitism was higher at the University of Florida Everglades Research and Education (EREC) in Belle Glade (50.4±11.8%) than at other locations in south Florida. Parasitism was comparable between fall and spring seasons, but was much higher in unsprayed fields (44.0±9.6%) than in the sprayed fields (15.0±2.5%). The two most common parasitoids that emerged from larvae were the solitary endoparasitoids Cotesia marginiventris (Cresson), found in 23 of the 25 sites sampled, and Chelonus insularis Cresson, found in 18 of the 25 sites sampled. Other parasitoid species that emerged from fall armyworm larvae were Aleiodes laphygmae (Viereck), Euplectrus platyhypenae Howard, Meteorus spp., Ophion flavidus Brullé, and unidentified species of Tachinidae. Techniques to improve the management of fall armyworm in overwintering areas of south Florida using conservation biological control are discussed.