Resistance in Maconellicoccus hirsutus (Green) in India to selected insecticides and quantification of detoxifying enzymes imparting resistance

Pink mealybug Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) is a destructive pest of agricultural and horticultural crops. Insecticides are the major tool used to control M. hirsutus. The present study was conducted to evaluate resistance to the commonly used insecticides acephate, dichlorvos, imidacloprid and buprofezin in M. hirsutus collected from seven different geographical locations of mulberry and vineyards in India. Detoxifying enzymes, namely esterase, glutathione S transferase (GST) and cytochrome P-450 (cyt-P450), were quantified in populations. One population from Erode showed a low level of resistance to acephate (resistance ratio RR] 10.3-fold), one from Salem showed a low level of resistance to dichlorvos (resistance ratio RR] 13.7-fold), one from Sangli showed a very low level of resistance to imidacloprid (RR 10.2-fold), and one from Chikkaballapur showed a low level of resistance to buprofezin (RR 14.8-fold). Activity ratios for detoxifying enzymes ranged from 1.8- to 4.9-fold for GST, 1.8- to 3.7-fold for esterase and 1.9- to 2.4-fold for cyt-P450. Furthermore, organophosphate resistance and activity of enzymes (esterase, GST and cyt-P450) were positively correlated. To contain the evolution of resistance to M. hirsutus infestation, buprofezin and imidacloprid could be used, supplemented with biointensive integrated management strategies and regular resistance monitoring programs.