Insecticidal Activity of Azadirachtin against Pulse Beetle (Callosobruchus maculatus Fab.) (Coleoptera: Bruchidae) Infesting Cowpea (Vigna unguiculata L.)

The toxicity of Azadirachtin (commercial product Nimbicidine®) was tested on three life stages of Callosobruchus maculatus viz., egg hatchability, larval survival and adult emergence. The concentrations used in the present experiment were 0.5, 1.0, 1.5, 2.0, 2.5 ml/100g of seeds. There was no egg hatching, larval survival and adult emergence in the highest dose level (2.5 ml/100 g seeds). It was also observed that the mean per cent egg hatching inhibition, per cent larval mortality change and per cent adult emergence suppression was highest in the higher dose of treatment 2.5 ml/100 g seeds (100 per cent) followed by other doses. Amongst all treatments tested for ovicidal, larvicidal and adulticidal potencies the treatment containing higher concentration with 2.5 ml/100 g seeds showed the significant effect in all the developmental stages.