Effect of Syzygium aromaticum essential oil on the common mosquito Culex pipiens (linneaus, 1758).

Abstract

This study aims to evaluate the insecticidal activity of clove (Syzygium aromaticum) essential oil, extracted through hydrodistillation, against fourth-instar larvae (L4) of Culex pipiens, a widespread mosquito species. Prior to the bioassays, an entomological inventory was conducted in two urban sites Guellal and Draâ El Miad which revealed the presence of several mosquito species belonging to the genera Culex, Culiseta, and Aedes. The genus Culex was the most diverse, with Culex pipiens being the dominant species in both sites: 67.73% in Guellal and 21.15% in Draâ El Miad. Other species such as Culiseta longiareolata and Aedes caspius also showed notable presence, indicating a more heterogeneous mosquito community in Draâ El Miad compared to Guellal. The yield of the essential oil was 0.79%. The parricidal activity was assessed following the World Health Organization (WHO) guidelines by determining the lethal concentrations (LC₅₀ and LC₉₀) at different exposure times (24, 48, and 72 hours). The results showed LC₅₀/LC₉₀ values of 7.37/64.39 pap after 24 hours, 5.2/19.19 pap after 48 hours, and 1.25/9.68 pap after 72 hours. In addition, the adulticidal activity was evaluated, and the LC₅₀ and LC₉₀ values were 0.56 ppm and 3.71 ppm, respectively. These findings indicate that Syzygium aromaticum essential oil has significant toxic effects against both larvae and adults of Culex pipiens, suggesting its potential as a natural and eco-friendly alternative to synthetic insecticides. Further research is recommended to confirm its efficacy and assess its environmental impact.