Acetone extracts of three selected plants induce toxicological and biological effects against the house mosquito, Culex pipiens (Diptera: Culicidae)

ABSTRACT: The biological effect of acetone extracts from three selected plants, Lantana camara, Rhazya astricta, and Citrullus colocynthis, on the egg hatch rate, larvicidal activity, and larval development of Culex pipiens L. was investigated. The egg hatch rate of Cx. pipiens was significantly reduced (P<0.01) when the extracts of L. camara were used. Moreover, the used extracts significantly exhibited a variable larvicidal activity against the Cx. pipiens (P<0.001). The most toxicity was observed when the larvae were treated with the acetonic extract of L. camara, showing different toxicities with lower LC50s at 140.1 ppm after two days and 51.3 ppm after ten days. In this observed time, larvae suffered chronic toxicities (increased mortality with increasing exposure time and sublethal endpoints, such as decreased larvae development) when treated with used plant extracts, leading to 96.7% mortality with L. camara and 91.5% and 85.7% mortalities with C. colocynthis and Rh. stricta, respectively. All concentrations significantly obstructed larvae development, causing significant reductions in both the proportion of pupation (P<0.001) and the emergence of adults (P<.001). The larval development reduction was observed under the L. camara extracts treatment, where only 15.2% and 9.7% of the larvae managed to reach pupal and adult stages, respectively. In conclusion, applying acetone extracts from L. camara to immature mosquito breeding sites may efficiently control mosquitoes to reduce the reliance on insecticides against these disease vectors.