Indian Journal of Agricultural Research

Investigation was conducted to test the insecticidal activity of sweet flag rhizome (Acorus calamus L.) extracts on Callosobruchus maculatus (F.) on cow pea in storage during 2016–2017 at the Department of Agricultural Entomology, Agricultural College and Research Institute, Coimbatore. Sweet flag (SF) extracts obtained by different extraction methods (soxhlet and mechanical shaker extraction) using various solvents viz., hexane, ethyl acetate and ethanol exhibited varied levels of insecticidal action on Callosobruchus maculatus (F.). Pulse beetle on cow pea seeds, there was a positive correlation between the concentration of the sweet flag extracts and the insecticidal action. The LC₅₀ value of hexane, ethyl acetate and ethanol extract of SF obtained in soxhlet extraction for C. maculatus was 0.042, 0.230 and 0.069 per cent at 48 hours, respectively. The LC₅₀ value of hexane, ethyl acetate and ethanol extract of SF obtained in mechanical shaker extraction for C. maculatus was 0.009, 0.275 and 0.069 per cent at 48 hours, respectively. Hexane extract of SF obtained from both extraction methods (soxhletand mechanical shaker) showed cent per cent mortalityat0.09 and 0.1 per cent on 5^th dayafter treatment (DAT). For ethyl acetate and ethanol extracts of SF obtained from both extraction methods (soxhlet and mechanical shaker), caused morethan 80 per cent mortalitywasobserved on 6^th DATat 0.09 and0.1 per cent on pulsebeetlerespectively. On 90 DAT, hexane extract of SF obtained from both extraction methods and of ethyl acetate extract of SF obtained from mechanical shaker extraction, there was no progeny development of C. maculatus at 0.05, 0.07, 0.09 and 0.1per cent concentrations. Cent per cent mortality and there is no progeny development C. maculatus in 0.09 and 0.1 per cent of hexane extract of SF (both extraction methods) and ethyl acetate extract of SF (mechanical shaker extraction) treated cowpea seeds upto 90 days when compared to untreated control.