It is estimated that after nearly half a century of synthetic pesticide application, mosquito-borne epidemic diseases such as malaria, filariasis, yellow fever, dengue and encephalitis are still affecting over two billion people. Malaria remains one of the leading causes of morbidity and mortality in the tropics. An estimated 300 to 500 million cases of malaria each year result in about one million deaths, mainly children under five, in Africa alone (WHO, 1997).