01 Oca 2026 Perşembe
Insecticides susceptibility of Culex quinquefasciatus from Southern part of West Bengal, India
Abstract : Culex quinquefasciatus, the primary vector of lymphatic filariasis (LF) in India, is mainly controlled through insecticide-based interventions. However, rising insecticide resistance poses a significant threat to these efforts. This study evaluated the insecticide susceptibility of Cx. quinquefasciatus populations from three different study sites (Barasat, Gaighata, Deganga) of North 24 Parganas, West Bengal. Immature stages of mosquitoes were collected from March to November 2023 and reared in laboratory conditions. F1 generation larvae and adults were used for susceptibility bioassays. Larval susceptibility to temephos was and adult susceptibility to DDT (4%), deltamethrin (0.05%), malathion (5%), and alpha-cypermethrin (0.05%) were assessed using WHO guidelines. Larval bioassays revealed moderate to high resistance to temephos, with LC₉₉ values ranging from 1.495 to 2.371 mg/L. Adult mosquitoes exhibited high resistance to DDT, deltamethrin, and malathion, with mortality rates below 67%. Alpha-cypermethrin showed probable resistance (90.63 - 94.38% mortality). Knockdown times were significantly prolonged, especially for DDT and deltamethrin, indicating reduced knockdown efficacy. These findings confirm widespread resistance across all tested insecticides, reflecting national and global trends. Immediate implementation of integrated vector management - such as insecticide rotation, biological control, and continuous resistance monitoring - is essential to preserve the effectiveness of LF elimination programs in India.