Assessing the resistance status of <scp> <i>Aedes aegypti</i> </scp> (Diptera: Culicidae) mosquitoes to conventional insecticides in Jeddah, Saudi Arabia

Abstract Dengue fever disease is an important health issue in the city of Jeddah, Saudi Arabia. Chemical pesticides play a vital role in dengue control, through combating the mosquito vector Aedes aegypti L. Standard methods recommended by the World Health Organization were applied in the current work to conduct resistance experiments in both adult and larval stages of Ae. aegypti mosquitoes against eight types of pyrethroid and organophosphorus pesticides used in control programs in Jeddah. The results prove that Ae. aegypti is resistant against the pesticides deltamethrin 0.05%, α ‐cypermethrin 0.05%, fenitrothion 1% and temephos, is tolerant with some degree of resistance against cyfluthrin 0.15% and λ ‐cyhalothrin 0.5%, as well as tolerant against malathion 5% and pirimiphos‐methyl 0.25%. On the other hand, the bacterial insecticide Bacillus thuringiensis ssp. israelensis ( Bti ) demonstrated high activity against the field strain of Aedes aegypti larvae, with a resistance ratio (RR) of 1.25. In general, we conclude from these findings that the continuous and frequent application of synthetic pesticides induces resistance in mosquitoes against pesticides. This, of course, forces us to reconsider the pesticides currently used in control programs and do our best towards finding alternative means to combat mosquitoes and the diseases that they can transmit.