Background: Mosquitoes such as Anopheles gambiae are primary vectors of malaria and pose significant threats to public health. Resistance to synthetic insecticides has prompted the search for plant-based alternatives. This study evaluated the larvicidal, adulticidal, and repellent activities of lemongrass (Cymbopogon citratus) oil against An. gambiae.

Methods: Lemongrass oil was purchased from a local herbal store in Kaduna, Nigeria. Larvicidal tests were conducted at concentrations of 5, 10, 25, 50, 100, 250, and 500 ppm using third- and fourth-instar larvae. Adulticidal assays were performed with topical/contact exposure at 0.5, 1.0, 1.5, and 2.0 mg/cm² with 25 female mosquitoes per replicate (4 replicates per dose). Repellent activity was assessed using a human arm-in-cage test with the same concentrations. Controls included ethanol and 10% DEET.