Some possibilities on the effectiveness of plant powders as grain protectants against cowpea weevil, Callosobruchus maculatus (Fabricius) Walp (Coleoptera: Bruchidae) infestation in chickpea

Concern has expressed that Pulse beetle (Callosobruchus maculatus) (F.) Walp has posed serious threat to stored pulse grains through voracious feeding. Therefore, the effects of leaf powders were tested using Withania somnifera L., Ocimum sanctum L., Albizia lebbeck L., and Dalbergia sisso Roxb., at 2% and 5% as protectants against C. maculatus in seeds of stored chickpea. The topics investigated included increase in the beetle population in relation to the initial population density, growth period and the intensity of feeding measured by percentage of damaged grains, percentage weight loss of grain and the amount of dust created (crumbled food, excreta, exuviae etc.). Results revealed that pest mortality was directly proportional to the concentration of the botanicals used. Seeds treatments of W. somnifera and O. sanctum at 2% and 5% concentrations were most effective against pest, while, D. sisso was the least effective treatment. However, W. somnifera showed a strong contact action against pest causing maximum mortality and sharply decreased its fecundity. The other plant powder O. sanctum at the higher concentrations (5%) afforded good protection against C. maculatus. The plant powders A. lebbeck and D. sisso did not significantly differ from each other but A. lebbeck gave good control against pulse beetle than check, while, D. sisso was at par to non treated control. Thus, W. somnifera and O. sanctum had significant effects on mortality of adults and larvae of C. maculatus, and significantly reduced F1 progeny indicating strong deterrence. The possible reasons for the differences may be biochemical response and persistence of the botanicals as protectants of gram against the C. maculatus.