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BACKGROUND Dusky cotton bug (DCB), Oxycarenus hyalinipennis (Costa) (Hemiptera: Lygaeidae), is a key insect pest of cotton. It causes huge losses to cotton and many other economically important crops. Sulfoxaflor is a newly introduced systemic insecticide that is effective against many sap‐feeding insect pests such as aphids, whiteflies and true bugs. The present study was designed to characterize the inheritance of sulfoxaflor resistance in DCB. Moreover, the role of synergists in reducing sulfoxaflor resistance in DCB was also assessed. RESULTS A field population of DCB has developed 1132.0‐fold resistance to sulfoxaflor after 11 selected generations in the laboratory. Nonsignificant difference of reciprocal crosses was observed depending on the LC50 (median lethal concentration) values (95% confidence intervals overlapped), suggesting an autosomal mode of sulfoxaflor resistance inheritance. The degree of dominance of 0.7 for F1 (Sulfo‐Sel Pop ♀ × Lab‐Pop♂) and 0.6 for F1'(Sulfo‐Sel Pop ♂ × Lab‐Pop♀), respectively, suggested that sulfoxaflor resistance was incompletely dominant. According to the monogenic model, the number of genes involved to induce sulfoxaflor resistance revealed that sulfoxaflor resistance was polygenic in nature. The realized heritability (h2) value for sulfoxaflor resistance was 0.2. The synergists experiment indicated that esterases were involved in the sulfoxaflor resistance mechanism in DCB. CONCLUSIONS The current results indicate that there is autosomal, incompletely dominant and polygenic inheritance of sulfoxaflor resistance in DCB. Our results would be helpful in delaying sulfoxaflor resistance against DCB in the field. © 2021 Society of Chemical Industry

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BACKGROUND: Oxycarenus hyalinipennis (Costa) (Hemiptera: Lygaeidae) is a polyphagous insect pest. In Pakistan, O. hyalinipennis is managed by using different insecticides, a major concern for cotton producers, and has developed resistance to many of these. Sulfoxaflor belongs to a newly released sulfoximine family that has high efficacy for controlling sap-feeding insect pests.RESULTS: A sulfoxaflor selected-population (Sulfo-Sel-Pop) of O. hyalinipennis showed a 3064.92-fold level of resistance after continuous selection for 18 generations with sulfoxaflor compared to unselected population (UNSel-Pop). The Sulfo-Sel-Pop showed a reduction in resistance (from 3064.92 to 635-fold) without exposure for five generations, indicating unstable resistance to sulfoxaflor. Cross-resistance studies of the Sulfo-Sel-Pop revealed no or very low cross-resistance to triazophos (0.42 to 0.30-fold), deltamethrin (0.85 to 0.18-fold) and acetamiprid (1.16 to 4.86-fold) from G 4 to G 19 compared to the field population (Field-Pop). The mean value of realized heritability was 0.15 in the Sulfo-Sel-Pop (G 19 ). Significantly reduced relative fitness was determined in the Sulfo-Sel-Pop (Rf = 0.21) followed by Crossand Cross 2 [(Sulfo-Sel-Pop ♀ × UNSel-Pop ♂) (Rf = 0.70)] compared with the UNSel-Pop. The values of intrinsic rate of natural increase (r m ), biotic potential (Bp) fecundity, egg hatching, and net reproductive rate (R0) were also significantly less in the Sulfo-Sel-Pop compared to UNSel-Pop. CONCLUSION: A very high fitness cost, unstable resistance and no or very low cross-resistance in the Sulfo-Sel-Pop have great implications in designing effective strategies for managing insecticide resistance to O. hyalinipennis.