Results/Conclusions Several field strains of *H.zea* collected in 2008 showed reduced Bt susceptibility compared to susceptible strains in diet incorporation bioassays. They also showed higher survival on Bt cotton leaves. Partial cDNA and genomic DNA sequences of the cadherin gene have been cloned from both field and lab susceptible strains. Sequence alignment has identified some changes between the resistant and susceptible alleles. We are currently investigating if these changes contribute to reduction in the susceptibility of those field strains.