Ovicidal and oviposition response activities of plant volatile oils against Culex quinquefasciatus say.
M.Ramar, S. Ignacimuthu and M. Gabriel Paulraj
The ovicidal and oviposition response of plant volatile oils was evaluated under laboratory conditions against Culex quinquefasciatus Say. Ten oils viz., aniseed, calamus, cinnamon oil, citronella, clove oil, lemon, orange, thyme, tulsi and vertiver were tested for ovicidal and oviposition response assays at five different concentrations viz., 12.5, 25, 50, 100 and 200 ppm concentrations. Among the ten oils clove, aniseed and cinnamon oils registered highest (100 ± 0.0 %) ovicidal activity at 200 ppm. Lemon (97.5 ± 0.5%) and tulsi (91.2 ± 0.6 %) oils were also highly effective against C. quinquefasciatus eggs at 200 ppm. Maximum oviposition response activity (100 ± 0.0%) was obtained in clove oil. The results indicate that both ovicidal and oviposition activity were dose dependent. It can be inferred from the investigation that the plant volatile oils are an effective agent for ovicidal and oviposition response against C. quinquefasciatus and further studies on identification of active compounds and field trials are needed to recommend the development of eco-friendly chemicals of botanical origin.