Ovicidal potentials of Calotropis procera and Parquetina nigrescens on Callosobruchus maculatus (F) (Coleoptera: Chrysomelidae)
Alamuoye Nathaniel O
This study evaluated the ovicidal potentials of the powder and solvent extracts of the leaf and root bark of Calotropis procera and Parquetina nigrescens on the ovipositional activities of Callosobruchus maculatus. These were with a view to developing a novel biological method of mitigating the problem of postharvest losses of cowpea seeds in storage due to infestation by C. maculatus. Different concentrations of powder, ethanolic and methanolic extracts of leaf and root bark of C. procera and P. nigrescens were prepared and used for oviposition and hatchability tests of eggs of C. maculatus. The results showed that the percentage reduction in number of eggs laid decreases with decrease in concentration of the plant extracts. The ethanolic extract of P. nigrescens leaf had the highest (69%) percentage reduction in number of eggs laid. Hatching percentage was lowest at 5% plant extract concentration and highest at 1% extract concentration and was significant (P< 0.05). The study concluded that the leaf and root bark of C. procera and P. nigrescens posses antiovipositional chemical compounds that could be used to control cowpea seeds infestation by bean weevil.