The efficacy of Vittallaria paradoxa seed oil against Callosobruchus maculatus(Fabricius) on cowpea treated seed was evaluated under ambient conditions (32±0.64°C and 68±3% R.H) at the Biological Sciences Department of Bayero University Kano. Callasobruchus maculatus were obtained from IITA Store in Kano State of Nigeria. The insect were reared and bred in the laboratory. The cowpea seed used for the bioassay were kept in the freezer overnight to eliminate maculatus infestation coming from field and the Moisture content was determined. The oil was extracted locally by steaming of dry seeds of Vittallaria paradoxa in a large cooking pot after pounding into paste in a mortar. Four different concentrations of seed oil (0.5, 1.0, 1.5 and 2.0 mL) were separately mixed with 20 g of cowpea in separate petri dishes which correspond to (2.5, 5.0, 7.5 and 10.0% v/w), respectively. Ten pairs of one-day old Callasobruchus maculatus were introduced into each petri dish. Number of eggs laid, viability of the eggs and adult emergence from each treatment were compared with the control and were found to be significantly reduced in comparison with the control treatment. It is concluded that Vittallaria paradoxa has great potential for use as a plant-based biopesticide for controlling pulse beetle Callasobruchus maculatus.
N. Abdullahi, Q. Majeed and T.I. Oyeyi, 2011. Studies on the Efficacy of Vittallaria paradoxa Seed Oil on the Oviposition, Hatchability of Eggs and Emergence of Callasobruchus maculatus (F.) (Coleoptera: Bruchidae) on Treated Cowpea Seed. Journal of Entomology, 8: 391-397.