Larvicidal efficacy of some Tephrosia species extracts against Anopheles Gambiae Ss and Culex Quinque fasciatus Say
Abdul Waziri Kidukuli, Sheila Mgole Maregesi, Joseph Saria, Nicolao Joseph Otieno, Yohana Lawi, Ramadhan Seleman Nondo, Esther Minza Innocent, Jane Mlimbila, Matobola Joel Mihale, Mainem Julius Moshi.
Abstract AIM:The study was conducted to evaluate the effect of some Tephrosia species against the larvae; Anopheles gambiae and Culex quinquefasciatus. These plants have proven to have insecticidal properties and regenerate quickly. Reduction of Mosquito borne diseases by killing mosquitoes at the larva stage is bio-control alternative method in the rural area since most of people cannot afford mosquito treated nets.
METHODS: The mosquito larvicidal test was performed on the two species by using ethanolic phyto-extracts according to World Health Organization (WHO) protocol with minor modifications.
RESULTS: Activity study of Tephrosia vogelii has shown that leaves are more active than other parts of the plants. The anopheles species exhibited more resistance compared to culex species by the factor of 4. The crude extract from the leaves of Tephrosia vogelii revealed 100% mortality rate against Anopheles gambiae at 235µg/ml and LC50 of 94.77µg/ml compared to 100% mortality rate against Culex quinguefasciatus at 55µg/ml and LC50 of 19.696µg/ml. The inter-species activity comparison indicated that larvicidal potential of Tephrosia species evaluated are in order of T. vogelii> T. vilosa,> T. aequilata,> T. pumila.
CONCLUSION: The findings revealed that, these species are potential alternative bio-control agents in the control of the mosquito borne diseases. Leaves exhibited better activity than other parts of the plant and the trends of the species activity towards both mosquito larvae after 72h exposure time are as followed: T. vogelii > T. vilosa > T. aequilata > T. pumila. Generally, Anopheles gambiae larvae were more resistant than culex quinquefasciatus. It is interesting to mention that, our results are comparable to the recently discovered larvicidal product called Bacillus Thuringiensis, subsp. Israeliensis (BTI®) claimed to be specific to targeted mosquito larva.