Susceptibility monitoring and comparative gene expression of susceptible and resistant strains of Spodoptera frugiperda to lambda-cyhalothrin and chlorpyrifos.

Background: Spodoptera frugiperda (J. E. Smith) is a widespread agricultural pest with several records of resistance to different insecticides and Bt proteins, including the neurotoxic insecticides chlorpyrifos (organophosphate) and lambda-cyhalothrin (pyrethroid).