Infectivity of Steinernema carpocapsae (Rhabditida: Steinernematidae) in Sterilized and Herbicide-Treated Soil

The infectivity of the entomopathogenic nematode, Steinernema carpocapsae (Weiser), against larvae of the greater wax moth, Galleria mellonella (L.), was investigated in sterile, nonsterile, and glyphosate-treated soil cores from a stand of bentgrass, Agrostis palustris Hudson. Soil cores were sterilized by high-pressure steam or methyl bromide fumigation. Another set of soil cores was treated with the herbicide, glyphosate. Nematode infectivity was significantly greater in sterile soil than in nonsterile and glyphosate-treated soil on days 3 and 8 after nematode application. No significant differences were detected by day 15 after nematode treatment. Results suggest the presence of a biotic factor(s) that limits the persistence of insect control provided by entomopathogenic nematodes in bentgrass.