Field evaluation of new insecticides against, scale insect, Hemilecanium imbricans (Coccidae: Homoptera) on mango
Prakash and Patil RR
The field experiment was conducted during 2013-14 and 2014-15 seasons in Navalur village in Dharwad district in Karnataka, India to know the effective chemical molecules for managing the scale insects. Among insecticides and biorationals tested, buprofezin 25 SC @ 1.25 ml/l, chlorpyriphos 20 EC @ 2 ml/l, acephate 75 SP @ 1 g/l, lambda-cyhalothrin 5 EC @ 0.5 ml/l, profenophos 50 EC @ 2 ml/l, and dichlorvos 76 EC @ 1 ml/l were the effective insecticides in chronologically in controlling all stages of scale insects under field conditions. But the usage of FORS @ 5 ml/l helped in dissolving the mealy wax coating of scale insects especially second instar onwards enabling effective penetration of the insecticides. Among the various instars, the first instars (crawlers) and second instars had more mortality to all treatments (139.38 per 20 cm length twig in acephate 75 SP @ 1 g/l and 163.25 and 163.88 second instar scales was recorded in dichlorvos 76 EC @ 1 ml/l and profenophos 50 EC @ 2 ml/l.) compared to third and fourth instars. This clearly indicated that crawlers were most susceptible to all imposed treatments because of their delicate, non-mealy/waxy body enabling the insecticides to come in direct contact with the insect.