The inhibitory function of Dimilin (Diflubenzuron), mostly a chitin synthesis regulator, on the ecdysis of mosquitoes (Anopheles gambiae s.l., Culex quinquefasciatus) and housefly was evaluated in the field and in laboratory. Three formulations of Diflubenzuron were evaluated in this study: Dimilin, Wettable powder (25%), Dimilin granules (2%), and Dimilin tablets (2%). The laboratory and field evaluation used different rates of concentrations of these formulations. Generally, at higher dosages larvae developments, eggs hatchability and pupation were impossible. The development of mosquitoes was significantly higher in control while highly depressed in different dosages of treatment in both laboratory and field experiments. In houseflies, the adult population decreased sharply after treatment of their breeding sites while pupae mortality was noticed to be high in laboratory-treated samples. Dimilin could be opted as one of the choice of the larval control chemicals to be incorporated in the integrated vector control programmes in urban and rural areas. 1. Introduction The mosquito Anopheles gambiae s.l., and Culex quinquefasciatus (Diptera: Culicidae) are the principal vector of malaria and filariasis in several tropical regions, respectively. Pesticide treatment has continued to be employed as the principal measure for their control [1]. However, resistance of mosquitoes to organochlorides, organophosphate, and pyrethroid pesticides have been reported in various studies [2–7]. These pesticides are frequently used for their control as well as in agriculture. The control of mosquitoes can best be achieved through integrated vector management [8, 9]. Although control of the adult mosquitoes by using insecticides, either in indoor residual spraying or by insecticide-treated materials, are currently the most widely used strategy [10–12], the control of larvae at their breeding sites is another suitable option [9, 13]. The strategy may reduce population of adult mosquitoes by proper and selective larviciding in the breeding habitats of mosquitoes. Larviciding involve the use of both chemical insecticides and the insect growth regulators (IGR) in controlling larvae of various insect pests [14–16]. The IGRs, unlike the chemical larvicides, are strictly arthropod-specific and environmental safe [17]. In public health, the larvicides are usually indicated for vectors or pests which tend to breed in permanent or semipermanent water bodies or places that can be identified and treated [18]. Therefore, larviciding programs can be complementary to control measures
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