Effects of tillage practices on entomopathogenic nematodes in a corn agroecosystem

Cultural practices such as tillage affect soil abiotic and biotic factors, which in turn may affect the survival and activity of entomopathogenic nematodes. We investigated the relative sensitivity of an inundatively applied nematode species, Steinernema riobrave (Texas), and two endemic nematode species, Steinernema carpocapsae and Heterorhabditis bacteriophora, to tillage practices in no-till and conventional-till corn near Goldsboro, North Carolina. Two baiting methods using Galleria mellonella, one conducted in the laboratory and the other in the field, were used to evaluate the nematodes in terms of infected insects and nematode persistence. H. bacteriophora, which was only rarely detected, was not significantly affected by tillage. Tillage had a significant negative effect on the detection of S. carpocapsae and a significant positive effect on the detection of S. riobrave. The nematodes' dissimilar sensitivities to tillage may be partly explained by differences in environmental tolerances and differences in tendencies to disperse deeper in the soil profile.