Evaluation of Insecticides for Control of Mango Mealybug (Drosicha mangiferae) in Bangladesh

Effectiveness of chemical insecticides namely Imidacloprid (0.4 g/L), Carbaryl (4 g/L), Thiamethoxam (0.4 g/L), Cypermethrin (1 ml/L), Carbosulfan (3 ml/L), Spinosad (0.4 ml/L), Dimethoate (2 ml/L) and Spirotetramate (2 ml/L) was evaluated to control 1^st, 2^nd, 3^rd instar nymphs and adult females of mango mealybugs (D. mangiferae) at Entomology laboratory, Sher-e-Bangla Agricultural University. Imidacloprid, Carbaryl, Thiamethoxam, Cypermethrin, Carbosulfan, Spinosad, and Dimethoate gave 90% mortality of 1^st instar nymph after 72 hr of spraying and dipping. At 2^nd instar, Cypermethrin, Carbosulfan, Spinosad, and Dimethoate gave 91.67%, 88.33%, 85.00%, and 85.00% mortality respectively by spraying method after 72 hr of treatment. In the dipping method, the highest mortality (90%) was achieved with Cypermethrin which was statistically similar to Carbosulfan (88.33%), Spinosad (86.67%), and Dimethoate (85%). At this nymphal stage, the lowest (63.33%) mortality was observed under Spirotetramate. In the case of the 3^rd instar, the highest (76.67%) and the lowest mortality (30.00%) was obtained with Cypermethrin and Spirotetramate respectively by spraying method. A similar trend was found in the dipping method. No mortality of adult females was found both in the spraying and dipping methods. Comparative susceptibility of 1^st, 2^nd, 3^rd instars and adult females showed that the 1^st instar nymph was more susceptible to all insecticides compared to 2^nd, 3^rd instar nymphs and adult females.