Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2009
Publication Date: 12/1/2009
Citation: Prasifka, J.R., Bradshaw, J.D., Meagher Jr, R.L., Nagoshi, R.N., Gray, M.E., Steffey, K.L. 2009. Development and feeding of fall armyworm, Spodoptera frugiperda, on Miscanthus x giganteus and switchgrass. Journal of Economic Entomology. 102(6):2154-2159. Interpretive Summary: As the U.S. strives to be more independent of foreign oil, biofuel research has become more important. Various crop plants are currently used for biofuel production, but there is a need for the cultivation of plants that offer fewer inputs (water, fertilizer, pesticides). Researchers at the University of Illinois and at the USDA-ARS CMAVE in Gainesville, Florida, conducted cooperative research to test whether a moth caterpillar would feed and develop on two potential biofuel production plants. Results showed that both the perennial grasses Miscanthus and switchgrass are potential hosts for fall armyworm. Future research will determine if this moth pest poses a threat under field conditions.
Technical Abstract: Observations of fall armyworm [Spodoptera frugiperda (J.E. Smith)] larvae infesting plots of Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize prompted laboratory-based tests of survival, development and feeding preferences on leaf tissue from M. x giganteus and switchgrass (Panicum virgatum L.). Survival from hatch to pupation was over 70% and 50% for fall armyworms reared on switchgrass and M. x giganteus, respectively, though survival of the S. frugiperda rice strain was significantly greater than the corn strain on both crops. Development times from hatch to pupation or adult emergence showed effects of crop and S. frugiperda host strain, but analysis of an interaction revealed development times for the rice strain were similar on both crops, while corn strain larvae showed delayed development on M. x giganteus relative to switchgrass. Analysis of larval (10 day) and pupal masses showed a similar pattern, with effects of crop and an interaction (at 10 days), but only the masses of corn strain larvae feeding on M. x giganteus were reduced relative to the other crop and strain combinations. In choice tests, neonates of both corn and rice strains showed a strong preference for feeding on young tissues rather than mature leaves of M. x giganteus or switchgrass, but also clearly favored corn leaves over either of the perennial grasses. Results indicate both plants are potential hosts for S. frugiperda, but additional information is needed to understand under which scenarios and to what degree fall armyworms may damage perennial grasses grown for biofuel production.