Sana Ullah1, Hammad Afzal Kayani1*, Sheeba Naz2, Hafiz Muhammad Ali3*, Rabya Fatima4, Fazal Haq4, Hina Ali Ahmed5, Muhammad Zubair Yousaf6, Jawaria Aslam7, Hafiz Muhammad Saif ur Rehman8, Nawal Sajid7
1Department of Biosciences, Shaheed Zulfikar Ali Bhutto Institute of Science and Technology, Karachi, Pakistan
2Dow College of Biotechnology, Dow University of Health Sciences, Karachi, Pakistan
3Department of Anatomy and Histology, The Islamia University of Bahawalpur, Pakistan
4Centre of Excellence in Science & Applied Technologies, Karachi, Pakistan
5Faculty of Life Sciences, Sardar Bahadur Khan Women’s University, Quetta, Pakistan
6KAM School of life Sciences, Forman Christian College University, Lahore, Pakistan
7Department of Physiology and Biochemistry, Cholistan University of Veterinary and Animal Sciences, Bahawalpur, Pakistan
8Department of Biosciences, Bahauddin Zakariya University, Multan, Pakistan
*Corresponding author’s email: hammad.afzal@szabist.edu.pk; hmali_uaf@hotmail.com
Received: 27 January 2026 / Revised: 16 April 2026 / Accepted: 01 May 2026 / Published Online: 12 May 2026
Abstract
Culex mosquitoes are important pathogens carriers to transmit West Nile virus and lymphatic filariasis, so accurate species identification and eco-friendly methods are necessary for proper control measures. The mosquito species (n=2094) collected from 19 different sites across Karachi region, were morphologically segregated intro 3 different genera (Aedes, Anopheles and Culex) by stereomicroscopy, followed by scanning electron microscopy and molecular identification of Culex by PCR. The molecular amplification of PCR product by agarose gel electrophoresis demonstrated a ~740 bp COI fragment and further confirmed the Culex species. The green synthesized silver nanoparticles (Ag NPs) using Aloe vera (AV) and Cassia fistula (CF) extracts were characterized by UV–Vis, SEM, EDS and FTIR. AV-Ag NPs were found smaller (≈65–79 nm) than CF-Ag NPs (≈80–95 nm) in size. In the larvicidal bioassay, the mortality of fourth-instar Culex larvae (n=20 / treatment) was recorded at 16, 32, 64 ppm of different NPs treatments, at 24, 48, 72 h post-treatment compared to the controls. AV-Ag NPs showed significantly (p<0.05) greater efficacy (98.30% mortality at 64 ppm at 72 h) than CF-Ag NPs (65.00% at 64 ppm at 72 h). Moreover, the probit regression analysis showed better LC₅₀=17.85 ppm and LC₉₀=42.51 ppm for AV-Ag NPs (72 h) as compared to LC₅₀=36.35 ppm and LC₉₀=361.38 ppm for CF-Ag NPs. Thus, the results demonstrated that Aloe vera–mediated Ag NPs are promising, eco-friendly larvicidal candidate for integrated mosquito control.
Keywords: Culex, Aloe vera, Cassia fistula, Silver nanoparticles, PCR
