Adulticidal and fe cundity effects of essential oils of Cymbopogon citratus and Tagetes minuta against Phlebotomus duboscqi

Abstract

Background: The efficacy of Cymbopogon citratus and Tagetes minuta essential oils in killing and fecundity of the adult females of the sand fly Phlebotomus duboscqi was tested in the laboratory. Materials and Methods: 1.0ml of each essential oil extract at co ncentrations of 0.125; 0.250; 0.500; 0.750 and 1mg/ml and the controls, DEET and Tween 80 were applied to the inner surface and bottom of a sterile pot and thirty adult P. duboscqi specimens aspirated into the pots . The parameters observed were insect mortalities after 24, 48 and 72 h as well as the number of eggs obtained from females subjected to the different treatments. Results: The results showed that both T. minuta and C. citratus oils were highly potent against P. duboscqi sandflies with mortality rates of 100.00 and 82.22 % on female sandflies and 100.00 and 88.89 % on male sandflies respectively after 72h. Between the two oils, C. citratus was significantly more potent ( P < 0. 05) and caused higher mortality than T. minuta against both male and female sandflies. However, there was no statistical difference in mortality rates between males and females subjected to each of the two oils at 24 h, 48 h and 72 h (P >0.05). Female sandflies treated with the oil of C. citratus oil had significantly lower mo rtality rates than those laid by sand flies treated with T. minuta oil (P< 0.05; P= 0.00084). Conclusion: I conclude that the two essential oils are prom ising natural insecticides due to their safety advantage over chemical insecticides. I do recommend further studies in the field using human subjects before their adoption for use against Phlebotomine sandflies.