Nitenpyram selection, resistance and biochemical characterization in dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae)

Dusky cotton bug, Oxycarenus hyalinipennis Costa, causes economic loss by sucking the moisture and oil contents from the leaves and seeds of cotton plants. Nitenpyram is commonly used to control O. hyalinipennis; however, resistance has been reported in field populations of Pakistan. The effect of nitenpyram resistance on the activities of detoxifying enzymes i.e., alkaline phosphatases (ALP), acid phosphatases (ACP), acetylcholinesterase (AChE), glutathione S-transferase (GST) and esterase (EST) upon continuous selection in laboratory was examined. The results showed that nitenpyram selected (Niten-SEL) O. hyalinipennis developed resistance of 22610-fold as compared to unselected (UNSEL) population and 2521-fold as compared to the field population (G(1)). ACP showed maximum activity (47.0 mu mol/min/mg of protein) in Niten-SEL (G(15)), followed by ALP (9.42 mu mol/min/mg of protein), AChE (3.06 mu mol/min/mg of protein), EST (0.77 mu mol/min/mg of protein) and GST (0.58 mu mol/min/mg of protein) as compared to field (G(1)) and UNSEL (G(17)) populations. The findings of the current study suggest that enhanced activities of detoxification enzymes might contribute to resistance development in O. hyalinipennis. Assessment of insecticide resistance mechanisms in O. hyalinipennis can help to develop integrated management plans to overcome resistance through use of enzyme inhibitors.