Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 19 3 2025 12 23 1844 1844 EN Wail Hassan Razi UniveDepartment of Plant Protection, College of Agriculture, Razi University, Kermanshah, Iranrsity Abbas Ali Zamani Department of Plant Protection, College of Agriculture, Razi University, Kermanshah, Iran Yousif Rashid Department of Biological Control, Al-Mussaib Technical College, Al Furat Al Asat Technical University, Iraq Arezoo Jamshidi Department of Plant Protection, College of Agriculture, Razi University, Kermanshah, Iran 2025 04 19 2025 12 15 Background: Culex pipiens (Diptera: Culicidae) poses a persistent global health challenge. The overuse of synthetic insecticides has led to resistance and environmental damage, underscoring the need for sustainable alternatives. Melia azedarach (Meliaceae) represents a promising source of bioactive com­pounds. This study aimed to comprehensively evaluate the potential of alkaloid extracts from M. azedarach against all life stages of Cx. pipiens and to characterize their phytochemical composition. Methods: Crude alkaloid extracts were prepared from both plant parts. Ovicidal, larvicidal, pupicidal and adult repellent effects, were assessed through laborato­ry bioassays. The chemical profile of the extracts was determined using Gas Chromatography-Mass Spectrometry (GC-MS). Results: Bioassays demonstrated significant ovicidal activity, with 100% egg mortality at 1% (w/v) concentration. Lar­vicidal activity was also notable at 1% (w/v). The fruit extract caused 100% mortality across the first three larval instars, while the leaf extract caused 100% mortality in the first two instars and 96.6% in the third. In the fourth instar, larvae showed 93.33 and 91.67% mortality with the fruit and leaf extracts, respectively. The extracts exhibited significant repellent effects, with rates of 63.00% and 60.00% at 1% (w/v) and consistently negative equilibrium ratios. GC-MS analysis showed the fruit extract was rich in insecticidal fatty acid esters, while the leaf extract contained repellent terpenoids like Piperitenone Oxide. Linoleic acid was a major shared compound, potentially underpinning the broad-stage efficacy. Conclusion: These findings support the use of M. azedarach extracts as a promising, locally accessible and environ­mentally responsible strategy for integrated Cx. pipiens mosquito management. https://jad.tums.ac.ir/index.php/jad/article/view/1844 https://jad.tums.ac.ir/index.php/jad/article/download/1844/702