The entomogenous nematodes Steinerema feltiae and S. bibionis did not penetrate the roots of corn, Zea mays, to infect larval northern corn rootworm (NCR), Diabrotica barberi, feeding within. Laboratory bioassays against first instar NCR indicated that S. feltiae, Mexican strain (LD = 49 nematodes/insect) is more virulent than S. bibionis (LD = 100). Numbers of NCR larvae in a grain corn crop were reduced by both nematode species applied at corn seeding time at the rate of 10,000 infective-stage juveniles per linear meter of corn row. The chemical insecticide fonofos provided significantly better control than either nematode species.
Keywords: Diabrotica barberi; Steinernema bibionis; Steinernema feltiae; biological control; corn rootworm; entomogenous nematode; fonofos.