Repellent activity of Eucalyptus and Azadirachta indica seed oil against the filarial mosquito Culex quinquefasciatus Say (Diptera: Culicidae) in India

The mosquitoes are a serious threat to public health, since they are known vector of many life-threatening diseases like malaria, filariasis, Japanese encephalitis, chikungunya and dengue fever, which are transmitted by the species of three mosquito genera: Anopheles, Culex and Aedes. Repellency is an important way of preventing vector-borne diseases by reducing man-vector contact. Most commercial repellents are prepared by using chemicals like N, N-diethyl-3methylbenzamide (DEET), dimethyl phthalate (DMP) and allethrin, and the most common mosquito repellents available in the market contain DEET [1]. The effective dose of DEET has been documented as 0.000 7 mg/cm for Aedes aegypti (Ae. aegypti), Anopheles maculates (An. maculates) and Culex quinquefasciatus (Cx. quinquefasciatus) [2]. But, these chemical repellents are not safe for public use because of their potential toxicity. Moreover, extensive use of the chemical agents for the control of vectorborne diseases has created problems related to adverse environmental effects, high operational cost, community acceptance and physiological resistance to vectors [3]. The mosquito Cx. quinquefasciatus Say (Family: Culicidae) is the potential vector of bancroftian filariasis throughout the world including India, but the control of Cx. quinquefasciatus-borne diseases are becoming increasingly difficult due to the reasons mentioned above. It is needful to develop environmentally friendly, long-lasting, low cost and preferably locally available repelling agents for mosquito control. The biologically active materials derived from plant sources have been reported either as insecticides for killing larvae or adult mosquitoes, or as repellents for mosquito biting. They are one of the best alternatives for mosquito control [4, 5]. Most plant-based insect repellents contain plant oils including Eucalyptus and Azadirachta indica (A. indica) oils. Preliminary studies suggest that Eucalyptus oil provides longer protection than other available plant-based repellents [6]. The oils extracted from turmeric (Curcuma longa), citronella grass (Cymbopogon winterianus) and hairy basil (Ocimum americanum) repelled the mosquito vectors Ae. ARTICLE INFO ABSTRACT