Characterisation of field-evolved resistance to chlorantraniliprole in the diamondback moth, Plutella xylostella, from China

Background Chlorantraniliprole and flubendiamide belong to the new chemical class of diamide insecticides. High levels of resistance to chlorantraniliprole rapidly evolved in field populations of Plutella xylostella from southern China. An investigation was made of diamide cross-resistance, as well as inheritance, stability and metabolic mechanisms of chlorantraniliprole resistance in field populations of P. xylostella from southern China. Results Three field populations of P. xylostella collected from southern China in 2011 showed high levels of cross-resistance between chlorantraniliprole (181150-fold) and flubendiamide (15800-fold) when compared with a susceptible reference strain. Genetic analysis showed that chlorantraniliprole resistance in the ZC population was autosomal and incompletely recessive. In the absence of selection pressure, resistance to chlorantraniliprole in the ZC population declined from 2040-fold (G1) to 25-fold (G7). The ZC-R strain (derived by selection from ZC) exhibited 670-fold resistance to chlorantraniliprole, which is synergised by known metabolic inhibitors such as PBO, DEM and DEF at low levels. Conclusion Field-evolved resistance to chlorantraniliprole in P. xylostella confers strong cross-resistance to flubendiamide, so both compounds should be well separated and not alternated in resistance management strategies. High-level resistance to chlorantraniliprole in the ZC population was incompletely recessive and not stable. Metabolic detoxification was involved in chlorantraniliprole resistance in the ZC-R strain to some extent, but target-site resistance could not be excluded. (c) 2012 Society of Chemical Industry