Insecticidal Effect of Aqueous Extracts of Eucalyptus and Neem Leaf in Comparison with Conventional Pesticides (Imidacloprid and Cypermethrin) on Cowpea Aphid in the Field Crop

Abstract

Insecticidal effect of aqueous extracts of Eucalyptus and Neem leaf extracts were compared with conventional pesticides (Imidacloprid and Cypermethrin) on cowpea aphid in the field, in a Randomized Complete Block Design, with treatments replicated four times. The study was conducted at the Students’ Research and Demonstrated Farm, Prince Abubakar Audu University, Anyigba, Kogi State, Nigeria. The trial consisted of a variety of cowpea (Sampea-9) treated separately to Eucalyptus and Neem leaf extracts, Imidacloprid and Cypermethrin, as well as a control, with all treatments replicated four times. Treatment effects on leaf damage, plant canopy height, number of pods per plant, pod length, pod damage, 100-seed weight, yield / hectare were assessed. Pesticide mitigation processes employed significantly (p ≤ 0.05) influenced plant canopy heights, number of damaged leaves, pods / plant, pod length, number of damaged pods, seeds / pod, 100-seed weight and grain yield / ha. Conventional pesticides consistently performed better than the botanicals across all parameters taken, while better performances were observed in Imidacloprid over Cypermethrin. Neem extract consistently did better than Eucalyptus extract regarding all parameters measured. Despite the better performances observed in synthetic pesticides compared to the botanicals, the health concern to humans, wildlife, as well as the environment needs to be considered. That Neem and Eucalyptus extracts gave good responses may offer alternative source of aphid control, considering that these alternatives are cheaper, readily available and do not pose health issues to the farmer or his environment. Farmers may be advised to combine both botanicals for optimum results.