Alouani Abdelouaheb, Rehimi Nassima, Soltani Noureddine
Under laboratory conditions, the toxicological evaluation of Azadirachtin and Bacillus thuringiensis israelensis (B.t.i) against the eggs of the mosquito Culex pipiens was conducted. The study assessed the biological effects of these compounds on larvae, pupae, and adult emergence, as well as their ovicidal activity after 24 hours of exposure to varying concentrations. The data indicated a significant reduction in the percentage of egg hatch when treated with Azadirachtin, showing values of 31.41% at 1 mg/L and 91.51% at 0.125 mg/L. Additionally, there was high mortality with increased concentration and prolonged larval and pupal development observed from eggs treated with Azadirachtin; 4.55 days at 0.125 mg/L and 7.66 days at 1 mg/L in the first instar. Larval and pupal durations increased with higher concentrations of Azadirachtin. The results also indicated a high augmentation in the percentages of malformations with decreased concentrations of Azadirachtin. In the adult stage, a significant reduction in total eggs laid, hatchability percentage, and longevity was observed. No adverse effects were noted after treatment with B.t.i. Conclusively, Azadirachtin shows excellent potential as an agent for controlling the mosquito Culex pipiens.