Susceptibility of Spanish populations of the corn borers Sesamia nonagrioides (Lepidoptera: noctuidae) and Ostrinia nubilalis (Lepidoptera: Crambidae) to a Bacillus thuringiensis endotoxin

Baseline susceptibility to the Cry1Ab delta-endotoxin from Bacillus thuringiensis (Berliner) was determined for four populations of Sesamia nonagrioides (Lefebvre) and two populations of Ostrinia nubilalis (Hubner) from Spain. This study shows that S. nonagrioides is at least as susceptible as O. nubilalis to B. thuringiensis Cry1Ab protein. We found small differences in susceptibility among the Spanish populations of S. nonagrioides that can be attributed to natural variation, because there are no records of B. thuringiensis products being used on corn crops in Spain. There were no differences in susceptibility to Cry1Ab toxin between the two populations of O. nubilalis.