Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2011
Publication Date: 12/28/2011
Citation: Hay-Roe, M.M., Meagher Jr, R.L., Nagoshi, R.N. 2011. Effects of cyanogenic plants on fitness in two host strains of the fall armyworm (Spodoptera frugiperda). Journal of Chemical Ecology. 37:1314-1322. Interpretive Summary: The fall armyworm (Spodoptera frugiperda) is a pest that attacks various economical important crops in the United States, such as corn, turf grasses, cotton and peanuts. Scientist at the USDA, ARS, Center for Medical Agricultural and Veterinary Entomology in Gainesville, Florida, determined that the insects that attack the corn fields suffered higher mortality when fed ‘Florona’ stargrass, a grass with naturally high cyanide levels, than those insects that attack grasses which are more resistant to cyanide. It may be that Cyanide susceptibility maybe evidence of separate populations that could differ in other ways as well. Understanding these differences will allow better targeting and pest control.
Technical Abstract: The generalist species fall armyworm, Spodoptera frugiperda (J. E. Smith) is actually composed of two genetic subgroups (host strains) that infest a wide range of host plants, including several of agricultural significance. Currently, little is known about the physiological factors that drive host preference differentiation. This paper describes a feeding study using natural plants and dietary cyanide in an artificial diet. The two host strains differed in their susceptibility to cyanogenic compounds. Larvae of both host strains were fed stargrass (Cynodon nlemfuensis var. nlemfuensis), a grass with naturally high cyanide levels. Corn strain larvae eliminated more cyanide through excreta and experienced higher mortality than when fed corn (low cyanide levels). Rice strain larvae experienced lower mortality than corn strain larvae. A survey of the cyanogen levels in the known plant hosts of fall armyworm is provided and the role of cyanide susceptibility in driving plant host preference is discussed. Cyanide resistance differs between the two strains of the fall armyworm.