Abstract:

Susceptibility tests have been successfully used for many years to determine insecticide resistance raised in pest and vector insects, including An. sacharovi,the primary human malaria vector in Turkey. As this method does not provide sufficient information about physiological resistance, an alternative method of enzyme tests based on biochemical and genetic evaluations has been developed. In this study, both methods were used for comparison. First of all, susceptibility to insecticides was tested in adult females of An. sacharovi collected in different seasons from Tabaklar and Herekli Villages, where insecticides are used intensively for both agricultural and vector control purposes, and from Menekse Village, where insecticide applications are more limited. Samples taken from laboratory colonies consisting of mosquitoes under non-insecticide pressure during the gonoactive season were also tested for comparison with the field material. In the susceptibility test using lethal doses of DDT 4%, Malathion 5%, Propoxur %1, Deltamethrin 0.025% and Permethrin 0.25%, each sample was divided into resistant and susceptible groups, then the changes in the activity levels of enzymes were studied in these groups. Three enzymes were tested; Acetylcholine Esterase (AChE), which is the target site in organophosphate and carbamate insecticide resistance, Glutathione S-Transferase (GST), which has a significant role in the detoxification of organochlorine and pyrethroide insecticides, and non-specific General Esterase, which has a role in the detoxification of all insecticides. The activities of the three enzymes were found at higher levels in the resistant groups than in the susceptible groups and also at higher levels in the gonoactive period than in the hibernation season. It was also found that AchE, GST and General Esterase enzyme activities were higher in localities receiving intensive insecticide application than in localities where insecticides are used in smaller quantities or not at all.

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