Fall Armyworm Symposium: Seasonal Chronology of Noctuidonema, an Ectoparasitic Nematode of Adult Moths, in Tropical and Subtropical America

A. M. Simmons, C. E. Rogers, K. U. Buckmire, B. Gray, K. D. Monkman, A. Pantoja, J. R. Raulston, V. H. Waddill

Abstract


Male moths of the fall armyworm, Spodoptera frugiperda (J. E. Smith), were examined for Noctuidonema guyanense Remillet and Silvain, an ectoparasitic nematode of adult Lepidoptera, during a 1-year (mid-September 1988 to mid-September 1989) study at locations in tropical and subtropical America (Hamilton, Bermuda; Belle Glade, Florida; St. Georges, Grenada; Panama, Republic of Panama; Isabela, Puerto Rico; and Weslaco, Texas) and in Tifton, Georgia. Host parasitism and nematode population density varied among locations and over time. Overall parasitism of S. frugiperda males averaged about 30%, with about 30 nematodes per parasitized moth. However, parasitism averaged 77% in Grenada, but only about 1% in Texas. Nematodes were more numerous at lower latitudes than higher latitudes. Nematode densities were correlated with temperature and humidity. However, because seasonal fluctuations of nematode populations occurred at locations with fairly stable climatic conditions, other factors (e.g., host migration and age of the host) may also affect the nematode populations.

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