Comparative efficacy of root, bark and leaf powders of Dracaena arborea for the control of two storage insect pests

摘要

Laboratory investigations were carried out to compare the efficacy of root, bark and leaf powders ofDracaena arboreafor the control ofSitophiluszeamaisandCallosobruchus maculatuson stored maize and cowpea grains, respectively. Two levels of concentration (1 and 5%) of the different powders were admixed with grains to determine the contact toxicity, damage assessment, progeny development and grain germination. The leaf powder at 5% concentration was more effective than the bark and root powders against the two insect species. The leaf powder at 5% concentration recorded a significant (P & 0.05) mortality of 26% againstS. zeamaisand 83% mortality againstC. maculatusafter 96 h of exposure. Mean damage in treated grains was as low as 1.09 to 3.23% compared with 4.64 to 16.16% in the control. Progeny production was significantly (P & 0.05) inhibited in treated grains while grain treatment did not affect germination.