Biological Sciences

Studies were carried out to examine the insecticidal properties of powdered extract of four plant species, namely Allium sativum (L.) (bulb), Drimia maritima (L.) Baker (bulb), Erythrina senegalensis (L.) (stem bark), and Khaya senegalensis (Desr.) (stem bark), against maize weevil (Sitophilus zeamais Motschulsky) infestation on stored maize (Zea mays L.). The efficacies of the plant powders at four levels of concentration (0.5, 1.0, 2.5, and 5.0 g) on maize weevil (S. zeamais Motschulsky) mortality monitored over 24-, 48-, 72-, and 96-hour intervals were assessed and compared to the industrially formulated insecticide, Coopex (Permethrin 0.5%), using the standard method, respectively. The results obtained revealed that the powdered extract of the four plant species evaluated showed varying degrees of efficacies at certain levels of concentration. The infested maize grain treated with bulb powder of A. sativum (L.) and stem bark powder of K. senegalensis (Desr.) proved to be the most efficacious with recorded lethal doses (LD 50) of 0.07 and 0.08 g, respectively, after 24 hours. Bulb powder of D. maritima (L.) Baker and stem bark powder of E. senegalensis (L.) had an LD 50 of 5.10 and 0.20 g, respectively, after 24 hours. On the strengths of these findings, it is evident that A. sativum (L.) and K. senegalensis (Desr.) are potential plant materials for bio-control of maize weevil (S. zeamais Motschulsky) infestation on stored maize grains.