Resistance in the European com borer, Ostrinia nubilalis (Hubner), to a commercial formulation of Bacillus thuringiensis (Bt)Berliner toxin, Dipel ES, appears to be inherited as an incompletely dominant autosomal gene. This contrasts with the inheritance of resistance to St in other insects, where it has usually been characterized as a recessive trait. The proposed high-dose/refuge strategy for resistance management in St maize depends on resistance being recessive or partially recessive, if field resistance turns out to be similar to this Laboratory resistance, the usefulness of the high-dose/refuge strategy for resistance management in Bt maize may be diminished.