IntroductionInsects are carriers of diseases to humans, other animals and plants. Centuries ago, they have been suggested as being possibly entailed in the spread of disease, especially with the outbreak of war (MacGregor, 1918). In 1577 Mercurialis, an Italian physician, suggested that plague, which was then ravaging Europe, was spread by flies feeding upon the diseased and dead, and later depositing fecal matter on food consumed by healthy persons (MacGregor, 1918). The connection between insects and diseases such as Yellow fever, Malaria, Anthrax, Filaria were also established a long time ago (MacGregor, 1918). The Dengue fever, whose global incidence has grown in recent decades was named as breakbone fever at the time and was stated as an insect-borne disease of unknown origin. Sandflies and mosquitoes were named as potential vectors, but the mosquito vectors were identified as Culex fatigans and Stegomyia fasciata (MacGregor, 1918). In 1937, Cook stated of 135 species of insects as vectors of viral diseases in plants. Species of aphids (causing "curl" disease to potatoes, Bermuda Lily disease) and leafhoppers (causing "Dwarf of Rice" disease in Japan, curly top disease of sugar beet in America) were identified as some of the important plant disease vectors (Cook, 1937).