Analysis of the chemical properties and larvicidal activity of essential oils from Ruta graveolens and Ruta montana against Culiseta longiareolata: Toxicity, enzymatic and biochemical alterations

Abstract

The mosquito Culiseta longiareolata (Diptera, Culicidae) is recognized as a vector for numerous detrimental diseases, necessitating efforts to maintain its population below threshold levels. In light of this, essential oils (EOs) are increasingly recognized as promising alternatives for improving pest management strategies. Therefore, this study intends to evaluate the larvicidal activity of Ruta montana and Ruta graveolens essential oils against Culiseta longiareolata (Aitken, 1954) (Culicidae). The GC-MS analysis detected 8 compounds in Ruta graveolens, primarily 2-Undecanone (47.72%) and 1-Nonene (22.56%). Conversely, Ruta montana revealed 6 compounds, with 2-Undecanone (64.35%) and 1-Octadecanol (15.90%) as its major constituents. The toxicity results revealed strong larvicidal activity against C. longiareolata larvae (L4), with LC₅₀ values of 30.24ppm for R. montana and 27.21ppm for R. graveolens. Furthermore, these essential oils significantly affect the biochemical composition of the larvae, leading to marked reductions in carbohydrates, lipids, and proteins. Notably, they also exhibit a detoxifying effect, as evidenced by substantial increases in biomarkers including glutathione S-transferase and catalase. These essential oils have the potential to serve as novel mosquito control agents derived from plant sources, offering an alternative to chemical larvicides.