Assessment of the toxic potentials of some plants powders on survival and development of Callosobuchus maculatus

Dried leaves powders of Guirea senegalensis, Piliostigma reticulatum and dried fruit powder of Piper guineense, were tested along side a conventional insecticide, Actellic-2-Dust, to compare their efficacies on survival of cowpea weevil ( Callosobuchus maculates ) during storage. Both the treated and untreated cowpeas (control) were then infested with newly emerged adult bruchids of both sexes. In all the trials, 83 to 100% mortality rates were observed in the treated samples. The rates in the untreated control ranges from 33.3 to 43.6%. The effects of the powders on fecundity were more pronounced on P. guineense and Actellic-dust treated samples. Similar effects were observed on development of immature stages and emergence of adult weevils. P. guineense had the highest larvicidal effects and lower productivity result especially. P. reticulatum had the lowest mortality rate and higher productivity result. The effects of the different powders were found to be dose related. Key Words: Cowpea weevil, Callosobuchus maculates , biological insecticides, Vigna unguiculata . African Journal of Biotechnology Vol.3(1) 2004: 60-62