Monitoring of Aedes albopictus Resistance to Common Insecticides in Futian District, Shenzhen

Background: This study aimed to investigate changes in the resistance of Aedes albopictus mosquitoes in Futian District, Shenzhen, to commonly used insecticides, providing a scientific basis for rational insecticide application and resistance management. Methods: Larval resistance to four commonly used insecticides was assessed using the World Health Organization (WHO)-recommended larval immersion method. Adult resistance was evaluated using the WHO-recommended adult contact tube method. Results: In 2025, Aedes albopictus larvae in Futian District, Shenzhen, exhibited high resistance to permethrin and beta-cypermethrin, with resistance ratios ranging from 224.6–239.5-fold and 88.3–118.8-fold, respectively. Low-level resistance was observed to propoxur and parathion, with resistance ratios of 3.3–3.4-fold and 4.0–4.9-fold, respectively. Adult Aedes albopictus mosquitoes showed resistance to permethrin and alpha-cypermethrin, with mortality rates of 8.9%–11.1% and 64.4%–72.2%, respectively. Possible resistance was detected to malathion and propoxur, with mortality rates of 87.8%–91.1% and 92.2%–94.4%, respectively. Conclusion: Aedes albopictus populations in Futian District, Shenzhen, have developed varying degrees of resistance to commonly used insecticides. Resistance to pyrethroid insecticides was markedly higher than that to carbamate and organophosphate insecticides. Insecticides should therefore be applied scientifically and rationally based on resistance surveillance results to improve control efficacy and delay the development of resistance.