Insecticidal Effect of Neem (Azadirachta Indica) Extracts Obtained From Leaves and Seeds on Pests of Cowpea (Vigna Unguiculata)

Insecticidal effect of two extracts of neem (Azadirachta indica) (leaves and seeds) in comparison with cymethoate and a control on pests and yield of cowpea was studied at the Research and Students' Demonstration Farm, Kogi State University, Anyigba, Kogi State, Nigeria in 2015. The treatment consisting of leaves and seeds extracts, cymethoate and a control were replicated four times in a Randomized Complete Block Design (RCBD). Effect of these treatments on the population dynamics of the insect pests, number of pods, pod weight, number of damaged pods and grains, 100-grain weight (g) and grain yield / ha were evaluated statistically as required for RCBD while significant means were separated using the Least Significant Difference (LSD) Test. Analysed results indicate that cymethoate effectively controlled field pests of cowpea such as whiteflies, aphids and pod borers resulting in less damaged leaves, less number of damaged pods and grains, higher pod numbers, 100-grain weight, better crop yield, among others. However, neem extracts also gave promising results compared with cymethoate, on population reduction in whiteflies, aphids and pod borers and comparable yield, though a little lower. Since better pest control and cowpea yield was obtained with neem extracts than the control, it can be concluded that these extracts exhibited reasonable insecticidal activities. Thus extracts from neem leaves and seeds can be employed as botanical in a more environmentally friendly and safe means of cowpea pest control, which is less expensive in comparison with synthetic herbicides.