Determination of resistance levels and enzyme activity of Tetranychus urticae Koch and T. turkestani (Ugarov & Nikolskii) (Acari: Tetranychidae) to acaricides commonly used in cotton in Aydın province

Objective: Tetranychus urticae Koch and T. turkestani (Ugarov & Nikolskii) populations were collected from cotton fields in Söke, Germencik, Koçarlı and Nazilli districts, where cotton cultivation is common in Aydın province, and their resistance levels to commonly used acaricides (abamectin, hexythiazox, etoxazole, spiromesifen) in the region were determined. In addition, it was investigated whether there is a relationship between detoxification enzymes (esterase, mono-oxygenases, glutathione-s-transferases) that play a role in acaricide resistance. Material and Methods: Eight populations of Tetranychus urticae and T. turkestani were collected from cotton fields in Aydın province. The German Susceptible Strain (GSS) population of T. urticae was used for comparison. First, the LC50 and LC90 values of the GSS population of T. urticae were determined against acaricides with the active substances abamectin, hexythiazox, etoxazole, spiromesifen. Then, the doses of LC90 values of these acaricides determined in the GSS population were applied to T. urticae populations collected from cotton fields and resistant populations were determined. Enzyme activity of T. urticae and T. turkestani populations determined as resistant was investigated. Results: The populations G15R21, K24R21, S3R21 of T. urticae exhibited high resistance to abamectin (223.66, 187.1, 223.02 fold), etoxazole (432.43, 156.68, 409.58 fold), hexythiazox (156.68, 156.31, 168.25 fold) and spiromesifen (1238.56, 1246.11, 981.77 fold). The populations G4G21, K16G21, S19G21 of T. turkestani showed high resistance to hexythiazox (176.54, 182.39, 164.34 fold) and they were found to be susceptible to the other acaricides. In addition, N1G21 and N11G21 populations of T. turkestani were susceptible to all acaricides. The highest esterase enzyme activity was 7.00, 6.48 and 6.89 mOD/min/mg protein in T. urticae G15R21, K24R21 and T. turkestani N1G21 populations, respectively; the highest GST enzyme activity was 15.14 and 14.86 mOD/min/mg protein in T. urticae S3K21 and T. turkestani K16G21 populations, respectively; The highest P450 enzyme activity was determined as 4.39 RFU/30min/mg in T. turkestani N11G21 population. Conclusion: All three populations of Tetranychus urticae showed high resistance to the four acaricides used in the study, while three populations of T. turkestani showed resistance only to hexythiazox. The other two populations of T. turkestani were susceptible to all acaricides. A relationship was also found between detoxification enzymes and resistance.