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Phytochemical Screening and Antifeedant Activity of the Seed Extracts Of Parkia Biglobosa against Cowpea Bean(Vigna Unguiculata) Storage Pest (Callosobruchus Maculatus)

Umar Muhd Sani

Peasant farmers in northern Nigeria indigenously use many plants to protect cereals and legumes against pest damage during storage. Phytochemical screening of the seed extracts of Parkia biglobosa indicated the presence of alkaloids, flavonoids, cardiac glycosides, polyphenols, tannins, and terpenoids in ethanol extract and alkaloids, steroids, terpenoids, flavonoids and saponins in petroleum extract. In this study the test insects (Callosobrucus maculatus) for the antifeedant efficacy were cultured and the first generation progenies that emerged were used. Beans were dressed with different doses (0.04, 0.08, 0.12, 0.16, and 0.20g) of the extracts and the seed damage data were used to estimate the weevil perforation index (WPI). WPI was found to have decreased as concentration of extracts increased. Compared to the control which has WPI of 50%, both extracts were found to be highly effective antifeedants against the cowpea weevil storage pest for the time allowed for the study. The ability to protect the seeds from damage has been clearly shown by the percent protectant ability (PPA) whose value at 0.20g dose for ethanol extract was 94.74% while for petroleum ether extract it was 81.82%. The ethanol extract was therefore more effective than the petroleum ether extract at the highest dose. The results of this study therefore showed that Parkia biglobosa seed extracts possessed some antifeedant activity which may be associated with the presence of the secondary metabolites detected by the phytochemical screening.