Characterisation of field‐evolved resistance to chlorantraniliprole in the diamondback moth, <i>Plutella xylostella</i>, from China

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p><jats:bold>Chlorantraniliprole and flubendiamide belong to the new chemical class of diamide insecticides. High levels of resistance to chlorantraniliprole rapidly evolved in field populations of <jats:italic>Plutella xylostella</jats:italic> 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 <jats:italic>P. xylostella</jats:italic> from southern China.</jats:bold></jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p><jats:bold>Three field populations of <jats:italic>P. xylostella</jats:italic> collected from southern China in 2011 showed high levels of cross‐resistance between chlorantraniliprole (18–1150‐fold) and flubendiamide (15–800‐fold) when compared with a susceptible reference strain. Genetic analysis showed that chlorantraniliprole resistance in the <jats:styled-content style="fixed-case">ZC</jats:styled-content> population was autosomal and incompletely recessive. In the absence of selection pressure, resistance to chlorantraniliprole in the <jats:styled-content style="fixed-case">ZC</jats:styled-content> population declined from 2040‐fold (<jats:styled-content style="fixed-case">G<jats:sub>1</jats:sub></jats:styled-content>) to 25‐fold (<jats:styled-content style="fixed-case">G<jats:sub>7</jats:sub></jats:styled-content>). The <jats:styled-content style="fixed-case">ZC</jats:styled-content>‐R strain (derived by selection from <jats:styled-content style="fixed-case">ZC</jats:styled-content>) exhibited 670‐fold resistance to chlorantraniliprole, which is synergised by known metabolic inhibitors such as <jats:styled-content style="fixed-case">PBO</jats:styled-content>, <jats:styled-content style="fixed-case">DEM</jats:styled-content> and <jats:styled-content style="fixed-case">DEF</jats:styled-content> at low levels.</jats:bold></jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p><jats:bold>Field‐evolved resistance to chlorantraniliprole in <jats:italic>P. xylostella</jats:italic> 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 <jats:styled-content style="fixed-case">ZC</jats:styled-content> population was incompletely recessive and not stable. Metabolic detoxification was involved in chlorantraniliprole resistance in the <jats:styled-content style="fixed-case">ZC</jats:styled-content>‐R strain to some extent, but target‐site resistance could not be excluded. © 2012 Society of Chemical Industry</jats:bold></jats:p></jats:sec>