Comparative Efficacy of Some Insecticides Against Aphid (Aphis Craccivora Koch) Infesting Groundnut in Relation to their Toxicity to Coccinellid Predator.

Field experiment was carri d out with four insecticides viz., demeton-o-methyl, dime-thoate, phosphamidon and malathion during kharif–1978 against black aphid. Aphis craccivora Koch infesting groundnut. Amongst four insecticides tested, demeton-o-methyl (Metasystox) 25% EC @ 400 ml/ha was found significantly superior in controlling the aphid. Insecticidal toxicity to coccinellid predator Coccinella septempunctata L. revealed that all the four insecticides were toxic to the grubs and beetles. However, the descending order of insecticides according to their toxicity to the predatory grub was malathion, demeton-o-methyl, dimethoate and phosphamidon. In this trial demeton-o-methyl was found to be the most effective systemic insecticide in controlling the aphid on groundnut even though it was moderately toxic to coccinellid predator.