Abstract
The house fly, Musca domestica L. (Diptera: Muscidae), is a significant vector for many pathogens and parasites. Presence of this vector causes economic losses due to decreased feeding activity in livestock, resulting in reduced yields of products. The repeated and unconscious application of chemical insecticides has resulted in the development of resistance in the majority of house fly populations worldwide. The aim of this research was to determine the susceptibility levels of two field M. domestica populations to cyfluthrin and etofenprox in Antalya, Türkiye. The LD(50) values, resistance ratios, and resistance status were determined by exposing adult house flies to the test chemicals for one hour. The Kemer population exhibited very low resistance to cyfluthrin, with a 5-fold increase, while the Serik population, in contrast, showed moderate resistance with a 29.67-fold increase. The resistance ratios of field populations to etofenprox were 2.33-fold (no resistance) for Kemer and 6.44-fold (very low resistance) for Serik, respectively. This is the first study to determine the resistance levels of house flies against cyfluthrin and etofenprox insecticides in Türkiye. To prevent or reduce the development of resistance to insecticides in house flies, integrated control methods and resistance management programs should be employed. Furthermore, it is advised that regular monitoring tests be conducted to observe the level of resistance.