Demonstration using field collections that Argentina fall armyworm populations exhibit strain-specific host plant preferences

MURÚA, M.G.; NAGOSHI, R.N.; DOS SANTOS, D.A.; HAY-ROE, M.M.; MEAGHER, R.L.; VILARDI, J.C.

JOURNAL OF ECONOMIC ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Lanham; Año: 2015 vol. 108 p. 1 - 11

0022-0493

Spodoptera frugiperda, the fall armyworm, is a major economic pest throughout the West-ern Hemisphere of corn (maize), cotton, sorghum, and a variety of agricultural grasses and vegetablecrops. Studies in the United States, the Caribbean, and Brazil demonstrated the existence of two subpop-ulations (previously designated ?host strains?) that differ in their choice of plant host. Specifically, thecorn strain is preferentially found in corn and sorghum, while the rice strain is dominant in rice, turfgrass, and alfalfa. However, inconsistent results were reported in surveys of fall armyworm in Argentina,with some indicating that the host plant preferences of the two strains might be compromised or evennonexistent. If correct, this would complicate efforts to control this pest by considerably expanding therange of habitats that would have to be considered as potential sources for fall armyworm infestations inspecific crops. A reexamination of Argentine fall armyworm, this time with field collections rather thanthe laboratory colonies used in previous studies, confirmed the existence of the two strains and their hostpreferences. Specifically, the corn strain was consistently the majority population infesting corn and wasusually so in sorghum, while the rice strain was predominant in pasture/turf grasses and alfalfa. The oneoutlier was a collection from rice, which had a corn strain majority. Overall, the data were generally con-sistent with strain behaviors observed in other areas of the Western Hemisphere.