Evaluation de l’activité larvicide de l’huile de la graine entière de Melia azeadarch sur le Culex pipiens

Abstract

Mosquitoes are harmful agents and vectors of many diseases for both humans and animals. The control of these blood-feeding insects depends on the use of chemical insecticides targeting the larval stages. However, pollution phenomena and resistance to various classes of chemical insecticides now threaten the environment in general and humans in particular. Aromatic plants are increasingly becoming a significant asset due to the valorization of their oils in various applications, including insecticidal effects. In this context, it is necessary to propose new non-polluting and specific alternatives, such as biopesticides. In the present study, the vegetable oil of Meliaazedarach from Eastern Algeria –Annaba-, extracted from the seeds, was tested against the L4 larvae of Culexpipiens under laboratory conditions. Bioassays were performed with different concentrations of the vegetable oil on newly eclosed 4th stage larvae, following the World Health Organization's recommendations, based on exposure times (24, 48, and 72 hours) to determine the larvicidal effect and assess lethal and sub-lethal concentrations (LC25, LC50, and LC90). The results obtained in this study indicate a good larvicidal potential of the whole Meliaazedarach seed oil against Culexpipiens, with a dose-response relationship inducing significant mortality rates after 24, 48, and 72 hours of exposure in the treated groups compared to the controls. The LC25, LC50, and LC90 values were calculated to be 121.9, 130.6, and 181.2 mg/L, respectively. Thus, plant derivatives can be considered as sources of biologically active agents that may be used for mosquito control in the future.