Resistance monitoring for eight insecticides in Plutella xylostella in central China

• The resistance status of P.xylostella was investigated in central China.
• The biological agents showed varying toxicity levels to P. xylostella populations.
• The newer insecticides showed high toxicity to P. xylostella populations.
• P. xylostella had high resistance for conventional insecticide beta-cypermethrin.

The diamondback moth, Plutella xylostella L., is one of the most important pests of cruciferous vegetables in the world. Assessment of changing insecticide resistance is essential for maintaining control efficiency and resistance management. In this study, four field populations of P. xylostella were collected from cabbage (Brassica oleracea, var. capitata L.) fields in central China from 2010 to 2012 to monitor their resistance to abamectin, Bacillus thuringiensis (BT) subsp. kurstaki (WG-001), spinosad, chlorfluazuron, chlorfenapyr, diafenthiuron, indoxacarb and beta-cypermethrin by using a leaf-dipping bioassay method. The results indicated that chlorfenapyr and diafenthiuron showed high toxicity to P. xylostella in central China, with no obvious toxicity change during the three years. The resistance of P. xylostella to spinosad was at low to moderate levels of resistance in all three years. Resistance of P. xylostella to abamectin, chlorfluazuron and indoxacarb varied greatly among the four regions. P. xylostella exhibited moderate and high levels of resistance to abamectin, chlorfluazuron and indoxacarb. The resistance of this pest to BT (WG-001) and beta-cypermethrin was severe in the four regions. Our study was conducive for developing a more effective resistance management program for P. xylostella.