Evaluation of bio-efficacy of different insecticides against aphids, Aphis craccivora in yard long bean, Vigna unguiculata subsp. Sesquipedalis

Abstract

Yard long bean, Vigna unguiculata subsp. Sesquipedalis is infested with many sucking pest viz., aphids, jassids, bugs, thrips and mites. Among the different sucking pests reported on yard long bean, aphids, Aphis craccivora are the major pest causing severe yield loss under field condition. Observations on the population counts of aphids were recorded one day before spraying and three, seven, ten and fifteen day after spraying on five randomly selected plants on three leaves from top, middle and bottom in each plot. Among the insecticides tested, the highest per cent reduction of aphids was recorded in the treatments imidacloprid 17.5 SL (86.89%) followed by acetamiprid 20 SP (84.50%), acephate 75 SP (79.29%) and diafenthiuron 50 EC (76.81%). However, least per cent reduction of aphid population was observed in azadirachtin 10,000 ppm (55.97 per cent) treated plot when compared to untreated control. Thus, it is concluded that all the studied insecticides proved effective against the aphids but the toxicity studies of the insecticides were observed from maximum to minimum in the following order, Imidacloprid > Acetamaprid > Acephate > Diafenthiuron > Spiromecifen > Fenazaquin > Chlorfenapyr > Azadirachtin.