Abstract

Efua N. Gideon , Akosua Adu Quarshie and Abedi Gyan Yeboah

The powders of the roots of S. longepedunculata with the roots of Zanthoxylum xanthoxyloides acting as reference product at two concentrations (1 and 5% wt/wt) were screened in the laboratory against S. zeamais and C. maculatus. The root powder of S. longepedunculata proved effective at 1 and 5% against S. zeamais and C. maculatus due to the presence 2-hydroxy-benzoic acid methyl ester (methyl salicylate, I) which is responsible of their biocide effect against the stored grain insects. Methanol extracts of root powders of S. longepedunculata and Z. xanthoxyloides were effective at 0.0, 0.04, 0.06 0.08 and 0.1 g/ml, significantly reducing (P<0.05) the development of eggs and immature stages and emergence of C. maculatus and S. zeamais progenies. The number of grains damaged by C. maculatus and S. zeamais were significantly reduced (P<0.05) by the extract of S. longepedunculata and Z. xanthoxyloides. These products also invoked 30-70% repellency against the beetles. The potential use of S. longepedunculata for the protection of stored product is discussed.