Effect of Monodora myristica seed oil on Callosobruchus maculatus fabricius infesting cowpea seeds (coleoptera: chrysomelidae: bruchidae) in the store

Abstract

Monodora myritica seed powder was prepared in the laboratory and was extracted with n-hexane using soxhlet procedure. The seed oil and powder were evaluated on Callosobruchus maculatus to study their effects on mortality, oviposition and adult emergence of the weevil. The results showed that the seed oil was the most toxic when compared to the powder. The seed oil caused 100 % mortality when treated at 2.0 % concentration by the 72 and 96 h post-treatment while the powder only caused 100 % mortality with the highest dosage of 2.0 g by 96 h after treatment. The oil and powder significantly reduced oviposition when compared to the controls. The seed oil completely prevented oviposition when treated at 2.0 % concentration and completely prevented adult emergence with 1.5 and 2.0 % seed oil concentration. The results obtained from this study showed that cotyledon oil and powder of Monodora myristica were effective in controlling cowpea weevil, C. maculatus and could serve as alternative to chemical insecticides for the protection of cowpea seeds against infestation by weevils