Monitoring Field Populations ofPlutella xylostella(Lepidoptera: Plutellidae) for Resistance to Eight Insecticides in China

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the main destructive insect pest of brassicaceous vegetables around the world. It has developed resistance to various classes of insecticides. However, the current status of insecticide resistance in P. xylostella has not been examined in China. In this study, concentration-mortality responses of P. xylostella to 8 insecticides, including abamectin, chlorantraniliprole, spinosad, beta-cypermethrin, chlorfenapyr, diafenthiuron, chlorfluazuron and the bio-pesticide Bacillus thuringiensis kurstaki (Btk) were evaluated. The results showed that almost all of the tested populations had developed high to very high resistance to abamectin and beta-cypermethrin, with resistance ratios ranging from 62.9 to 1494.7-fold. Chlorantraniliprole was very effective against P. xylostella in most tested populations except those from Taihe and Wuxi. Approximately 61% of tested populations displayed moderate resistance to spinosad, while oth...