The study on biocidal resistance of mosquitoes of genus Culex and Aedes to commonly used biocides cypermethrin and deltamethrin in Central Europe

Pyrethroid as an agent of biocide resistance (BR) and environmental contamination has become a major threat for global health and biodiversity conservation. After eradication of malaria in Europe, uncontrolled mosquito elimination performed just to decrease their nuisance became a long-term practice. Pyrethroids, compounds used for chemical control of mosquitoes are not selective. The main goal of this paper was to study the pyrethroid resistance among mosquitoes of genus Culex and Aedes in Central Europe. Experiment was performed by collecting mosquitoes of Culex spp. and Aedes spp. in four locations: Suchohrad, Vysoká pri Morave, Bratislava, and Bratislava surroundings, where pyrethroids are commonly used as a form of chemical control of mosquito population. The biocide resistance was determined by the CDC bottle bioassay. The second aim was the determination of presence and longevity of cypermethrin in the surrounding environment in the village Vysoká pri Morave. Samples were collected 7 days after ultra-low volume (ULV) fogging treatment in June 2021 and analyzed by liquid chromatography with tandem mass spectrometry (LS/MS). According to the results of performed tests we may state that in all tested localities there is a considerable possibility of occurrence of resistance of tested mosquitoes to deltamethrin and cypermethrin. Based on the results obtained by liquid chromatography with tandem mass spectroscopy from the collected vegetation samples we may conclude that the measured values of cypermethrin and deltamethrin exceeded the highest accepted measured residue levels (MRL) for food and animals products, and after the ULV treatment the population of mosquitoes increased.