The risk of insects evolving resistance to Bt transgenic crops is a major concern in agriculture. In Lepidoptera, one of the factors associated with resistance to Bt toxin is the cadherin Cry1A toxin receptor in the membranes of larval midgut cells. A cDNA encoding a putative Cry1A toxin receptor with high similarity to cadherin sequences identified in other Lepidoptera, was isolated from Sesamia nonagrioides (Lepidoptera: Noctuidae). Polymorphisms were identified in cadherin sequences from S.

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... onagrioides populations from three geographic regions in Greece. In addition, Barcoding-High Resolution Melting (HRM) analysis using mitochondrial cytochrome oxidase (COI) sequences were implemented to distinguish the different geographical populations of S. nonagrioides. The characterization of S. nonagrioides cadherin sequences in combination with an HRM-COI assay may serve as an efficient tool for distinguishing different Sesamia populations and potentially Bt resistant vs susceptible individuals aiming at rapid monitoring of Bt resistance in the field.