Insecticidal and repellent activities of medicinal plant extracts against the sweet potato whitefly, Bemisia tabaci (Hom.: Aleyrodidae) and its parasitoid Eretmocerusmundus (Hym.: Aphelinidae)

Toxicity and repellent activities of aqueous extracts of nine medicinal plants were evaluated on different life stages of the sweet potato whitefly, Bemisia tabaci. Tomato plants infested with whiteflies were dipped in 10% (wt/wt) of each plant extract for toxicity evaluation. Repellency was evaluated in a choice experiment with detached tomato leaves. All extracts evaluated were relatively ineffective against the adult stage. Extracts of Ruta chalepensis, Peganum harmala and Alkanna strigosa were effective in reducing the numbers of B. tabaci immatures similar to the reduction observed in the imidacloprid treatment. These three extracts were not detrimental B. tabaci parasitoid, Eretmocerus mundus. In addition, the plant extracts Urtica pilulifera and T. capita were repellent to B. tabaci adults. These results indicate that the extracts from the plants R. chalepensis, P. harmala and A. strigosa could act as a potential source for natural product developed for B. tabaci management.