Larvicidal effects of some natural products on the Aedes aegypti mosquito, a vector of dengue fever and Zika virus

Abstract

Natural products are considered a good choice in the biological control of mosquitoes because they are an effective way to eliminate larvae and prevent an increase in mosquito numbers, while simultaneously not polluting the environment or damaging health. This investigation was designed to study the potential toxicity of three species of algae, Caulerpa racemosa (Weber-van Bosse, 1909), Padina boryana (Thivy, 1966), and Turbinaria ornata (Turner J. Agardh, 1848), on the larvae of Aedes aegypti mosquito, the vector of dengue and Zika viruses. Among the studied species, Caulerpa racemosa showed the greatest effectiveness in eradicating A. aegypti larvae with an LC 50 = 43.5 ppm, followed by Padina boryana with an LC 50 = 51.93 ppm. Both species proved to be excellent candidates as a source of larvicidal agents and could be used commercially in mosquito control programs as eco-friendly biopesticides. The combined activity of different mixtures against mosquito larvae was expressed as the coeffective factor (C.F.). C.F. values showed that the joint activity of insect growth regulator Dudim in combination with Caulerpa racemosa and Padina boryana extracts produced degrees of potentiation effects and degrees of additive effects were obtained with Dudim in combination with Turbinaria ornata extract.