Insecticide resistance of Colorado potato beetle (<i>Leptinotarsa decemlineata</i>) in the province of Québec

Modern agriculture is facing an increase of insecticide resistance that is well illustrated by the Colorado Potato Beetle ( Leptinotarsa decemlineata; CPB). The purpose of this study was to characterize the resistance profile of CPB from 11 field populations in Québec. Bioassays were conducted by exposing second instar larvae to a potato leaf disk pre-dipped in an insecticide solution and comparing the mortality of these populations to that of a susceptible population (lab reared). Various levels of resistance were confirmed for nine insecticides in all populations. We draw possible links between the observed resistance and agricultural practices at the landscape scale.