IJSRP, Volume 5, Issue 5, May 2015 Edition [ISSN 2250-3153]
Onekutu, A, Nwosu, L. C. and Nnolim, N. C.
Seed powder of Afromomum melegueta, Piper guineense and Xylopia aethiopica at the rates of 0.5, 1.0 and 1.5 g/ 20 g seeds of cowpea were assessed for insecticidal activities against Callosobruchus maculatus Fabricius in the laboratory under fluctuating ambient temperature and relative humidity in Makurdi, Benue State, Nigeria. P. guineense caused the highest toxicity (68.53%) at 1.5 g/ 20 g cowpea seeds after 96 hours of exposure. Oviposition deterrency, larvicidal effect and suppression of adult emergence recorded for P. guineense was considerable but failed to match the conventional synthetic insecticide, Permethrin (P > 0.05). A. melegueta at test concentrations and at short storage duration (< 5 days) was not toxic to the bruchid. However, it significantly (P<0.05) deterred oviposition in C. maculatus females when compared to unprotected cowpea seeds. In the study, X. aethiopica protected cowpea seeds better than A. afromomum and gave minimal support to the bionomics of the bruchid. The study seriously suggests an increased need for search for botanical insecticides that can effectively control the resistant cowpea bruchid. Any natural material that cannot give good control of C. maculatus at an economically justified concentration in 24 hours may not be sustainable.