Susceptibility of field populations of the diamondback moth, Plutella xylostella, to a selection of insecticides in Central China

• Insecticide resistance in ten field populations of Plutella xylostella from China was monitored from 2013 to 2014.
• High resistance to Bt (Resistance Ratio (RR) = 167.36) and to beta-cypermethrin (RR = 159.96) in field populations of Plutella xylostella was detected.
• Significant correlations were detected between the values of log LC50 of chlorantraniliprole and cyantraniliprole.

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. However, resistance to insecticides evolves following heavy and frequent use. Therefore, the insecticide resistance in field populations of P. xylostella collected from Central China from 2013 to 2014 was determined with a leaf-dipping method. Based on the results of the monitoring, P. xylostella has developed high levels of resistance to beta-cypermethrin (resistance ratio = 69.76–335.76-fold), Bt (WG-001) (RR = 35.43–167.36), and chlorfluazuron (RR = 13.60–104.95) and medium levels of resistance to chlorantraniliprole (RR = 1.19–14.26), chlorfenapyr (RR = 4.22–13.44), spinosad (RR = 5.89–21.45), indoxacarb (RR = 4.01–34.45), and abamectin (RR = 23.88–95.15). By contrast, the field populations of P. xylostella remained susceptible to or developed low levels of resistance to diafenthiuron (RR = 1.61–8.05), spinetoram (RR = 0.88–2.35), and cyantraniliprole (RR = 0.4–2.15). Moreover, the LC50 values of field populations of P. xylostella were highly positively correlated between chlorantraniliprole and cyantraniliprole (r = 0.88, P = 0.045), chlorantraniliprole and spinosad (r = 0.66, P = 0.039), spinosad and diafenthiuron (r = 0.57, P = 0.0060), and chlorfenapyr and diafenthiuron (r = 0.51, P = 0.016). Additionally, the activities of detoxification enzymes in field populations of P. xylostella were significantly positively correlated with the log LC50 values of chlorantraniliprole and spinosad. The results of this study provide an important base for developing effective and successful strategies to manage insecticide resistance in P. xylostella.

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