Recent population outbreaks of Tetranychus urticae Koch (red form) (Acari: Tetranychidae) were observed in strawberry fields in southern Turkey. Growers frequently complained that acaricides becoming an inefficient means of controlling this polyphagous pest. Therefore, a laboratory based bioassay and biochemical tests were conducted to determine comparative acaricide resistance status of five fields and a lab population of T. urticae. Larval bioassays were conducted using etoxazole and spiromesifen, whereas adult bioassays were performed with abamectin and tebufenpyrad. Kinetic esterase and glutathione S-transferase (GST) enzyme activities were also determined using a microplate reader. When compared to the lab population, based on LC50 values, the resistance rations of field populations were found between 2.39–7.86, 6.80–15.39, 4.61–9.73, and 5.51–12.47-fold for abamectin, etoxazole, spiromesifen and tebufenpyrad, respectively. Total esterase and GST activities of field populations were much higher than of the lab population. A 7.72–10.69 mOD/min/mg protein and a 5.92–7.56 mOD/min/mg protein, esterase and GST enzyme activities were determined for field populations, respectively. Whereas these enzyme activities were found to be 3.83 and 5.49 mOD/min/mg protein for the susceptible lab population, respectively. The higher detoxification enzyme activities indicate that these two enzymes play an important role in metabolic pathway of acaricides in different T. urticae populations.
Physiological resistance alters behavioral response of Tetranychus urticae to acaricides
