Cross‐resistance patterns and fitness in fufenozide‐resistant diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

BACKGROUND: Fufenozide is a novel non-steroidal ecdysone agonist with good efficacy against diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae). At present, it is widely applied for the control of a range of lepidopterous pests in China. This study compared the activities of fufenozide and 12 other insecticides against unselected and fufenozide-selected strains of DBM to examine potential patterns of cross-resistance. The relative fitness of the fufenozide-selected strain was assessed to provide information pertinent to insecticide resistance management. RESULTS: Compared with the susceptible strain (JSS), the fufenozide-resistant strain (JSR) showed high cross-resistance to dibenzoylhydrazines and benzoylphenylureas, low cross-resistance to abamectin and no cross-resistance to organophosphates, carbamates and pyrethroids. JSR had a lower reproductive ability and a relative fitness of 0.5 compared with JSS. CONCLUSION: P. xylostella has the potential to develop resistance to fufenozide, albeit at the expense of fitness. Cross-resistance between the same and other classes of insecticides is of concern, and should be a key consideration when implementing fufenozide-based control strategies for this species.