Insecticidal Activities of African Nutmeg Solvent Extracts Against Cowpea Seed Bruchid, Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae)

Abstract

Background and Objective: Protection of stored products from reduction in quality and market value by insect pests have been promoted with the use of aromatic and medicinal plants that are eco-friendly and relatively cheap biopesticides. African nutmeg, Monodora myristica (M. myristica) (Gaertn) Dunal, an African spice was investigated for its insecticidal activities against cowpea seed storage bruchid using solvent of different polarities for extraction Materials and Methods: Extracts of the African nutmeg were evaluated at tropical ambient temperatures of 28±2°C and 75±5% relative humidity for their long-term protection ability against cowpea storage beetle Callosobruchus maculatus (C. maculatus). Indexes used were, seed damage, water absorption capacity and viability of treated seeds. Data was analyzed by one way anal. of variance (ANOVA) using SPSS. Results: All test extracts protected cowpea seeds against infestation by C. maculatus with 0% seed damage and weight loss during a 3 mo storage period at highest concentration of 0.6% v/w. Germination of seeds and water absorption capacity was not significantly affected (p>0.05) after treatment. Conclusion: The most effective extract was the steam distillate, although other solvents tested (methanol, ethanol, petroleum ether, n-hexane) also extracted the active ingredients in the M. myristica seeds for protection against beetle damage.