|Meagher, Robert - Rob|
|NUESSLY, GREGG - University Of Florida|
|HAY-ROE, MIRIAN - University Of Florida|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2016
Publication Date: 1/25/2016
Citation: Meagher Jr, R.L., Nuessly, G.S., Nagoshi, R.N., Hay-Roe, M.M. 2016. Parasitoids attacking fall armyworm (Lepidoptera: Noctuidae) in sweet corn habitats. Biological Control. 95:66-72.
Interpretive Summary: Florida leads the country in fresh market sweet corn production primarily in the south Florida counties of Palm Beach, Miami-Dade, and Hendry, where planting occurs from October to March. Sweet corn is plagued by several direct insect pests that are managed by as many as 20 insecticide applications per season employing 32 different labeled chemicals. One of the more serious insect pests is the fall armyworm (Spodoptera frugiperda), whose caterpillars attack both the whorl of the growing plants and the corn ear. Researchers with the USDA, Agriculture Research Service, Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, in collaboration with colleagues at the University of Florida collected over 8,000 caterpillars from sweet corn fields that either had been sprayed with insecticides or were unsprayed in order to identify the common parasites that attack fall armyworm. Two small wasp species were found in over half the 25 sampling sites with parasitism rates that averaged close to 30%. Modification of near field landscape is a potential conservation approach to biological control that may lower the number of applications made during the early part of the season.
Technical 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 – 2015 during the fall and spring seasons. Larvae were brought back 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 8,353 fall armyworm larvae were collected, 60.6% of which developed into moths after feeding on corn tissue and artificial diet. Parasitoids emerged from 2,363 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, and Chelonus insularis Cresson, found in 18 of the 25 sites sampled. The other parasitoid species that emerged from larvae were Aleiodes laphygmae (Viereck), Euplectrus platyhypenae Howard, Meteorus spp., Ophion flavidus Brullé, and unidentified species of Tachinidae. Techniques to improve management of fall armyworm in overwintering areas of south Florida using conservation biological control are discussed.