FORMULATION OF PLANT-DERIVED PESTICIDES FROM THE LEAF EXTRACTS OF Azadirachta indica A. Juss (Meliaceae) and Ocimum sanctum Linn. (Lamiaceae)

Azadirachta indica has been used in Nigeria for decades in traditional medicine for managing diseases such as fever, stomach ache, common cold, and urinary tract infections. Ocimum sanctum has found several traditional therapeutic uses in the treatment of diseases like a headache, cough, diarrhoea, constipation, warts, malfunction, nasal polyps and ulcer. This present study determined the effects of A. indica and O. sanctum leaf extracts on store-grain weevils (Acanthoscelides obtestus). Plant-derived pesticides were formulated from leaf extracts of A. indica and O. sanctum to determine the potency of these formulations on this pest. Insecticidal activities of the formulated pesticides were evaluated in five groups of bean- infested weevils (Acanthoscelides obtestus) at 5 mL, 10 mL, 15 mL, and 20 mL. All the formulations exhibited a dose-dependent percentage insecticidal activities (%IA). Results obtained were compared with that of standard “General insect killer” at p < 0.05 (one-way ANOVA) which has 100% IA. The study showed that pesticide derived from A. indica leaf extract had higher % insecticidal activity (IA) of 90% than pesticide derived from O. sanctum leaf extract which had 88% IA and the mixture of the two formulations which had 88% IA. Our study, therefore, showed that plant-derived pesticides possessed insecticidal activity with low lethal effect on humans and the environment, and should be incorporated in pest management in stored grains.