Evaluation of the Insecticidal Potentials of Some Indigeneous Medicinal Plants on the Warehouse Moth (<i>Ephestia cautella</i>) (Walker)

Abstract

Pulverized plant materials of Eugenia aromatica (Baill) (seeds), Aristolochia ringes (Varl) (roots), Zanthoxylum xanthoxyloides (Lam.) Waterman (roots) and Azadirachta indica A. Juss (stem bark) were evaluated for their insecticidal activities against the warehouse moth, Ephestia cautella (Walker) reared on cocoa beans. The materials were applied at dosage rate of 0.00% (control), 2.50%, 5.00%, 10.00% and 15.00% respectively at intervals of 24, 48, 72 and 96 hours of treatment in order to access their insecticidal efficacies as protectants of cocoa against the warehouse moth, Ephestia cautella infestation. The result of the experiment revealed that all the plant materials were very effective on adult mortality. Eugenia aromatica proved to be the most effective producing 70% adult mortality at a low dosage rate of 2.50% within 48 hours post-treatment and Azadirachta indica was the least of all the four plant materials used with regards to insecticidal potency, producing 50% adult mortality within 96 hours post-treatment. There was significant difference (p < 0.05) in the mortality recorded by all the plant materials especially at higher concentrations and exposure period. The results suggest the ability of using these plant materials for cocoa protection as a safe alternative to insecticides.

Keywords: Cocoa, Ephestia cautella, medicinal plants, efficacy evaluation, insecticidal.