Comparative Toxicity of some Selected Novel Chemistry Insecticides against Mealybug Drosicha mangiferae (Hemiptera: Pseudococcidae) Infesting Citrus Orchards in Pakistan

One of the emerging threats to citrus industry in Pakistan is the infestation of mealybug Drosicha mangiferae (Pseudococcidae: Hemiptera), a damaging insect pest of a large number of agricultural and horticultural crops in South East Asia. In spite of extensive applications of conventional synthetic pesticides, citrus farmers are unable to get rid of this pest. In order to find out alternate biorational pesticides, this laboratory study was carried out to evaluate few selected novel chemistry insecticidal formulations against 2nd instar nymphs of D. mangiferae using standard twig-dip bioassay method according to Completely Randomized Design. Results showed that both factors i.e. insecticidal treatments (F _{9, 245} = 146.90, P < 0.001) and time (F _{4, 245} = 445.75, P < 0.01) and their interaction (F _{36, 245} = 9.20, P < 0.001) had a significant effect on the mortality of mealybug nymphs. The most effective novel chemistry insecticides against D. mangiferae mealybugs were sulfoxaflor, spirotetramat, thiamethoxam and pyriproxyfen with mean mortality and LT50 values of 64.00±3.50% and 31.67 h, 62.67±2.64% and 34.42 h, 53.01±4.10% and 45.84 h, and 51.00±3.97% and 48.10 h, respectively. Based on these results, the above mentioned novel chemistry insecticides are recommended to be incorporated in future pest management programs against D. mangiferae mealybugs.