Determining the susceptibility levels of tetranychus urticae populations collected from antalya province and its districts to abamectin and bifenazate

Tetranychus urticae Koch. (Acari: Tetranychidae) cause considerably economic losses in many vegetables, fruits, industrial crops and ornamental plants. Resistance to acaricides in T. urticae is currently major problem in both Turkey and worldwide. Development of the "resistance management programme" was recommended against resistant populations. Determining the susceptibility levels of pest populations collected from local areas is the first step in resistance management. In this study susceptibility level of 7 T. urticae populations from Kepez, Aksu, Gazipaşa, Demre, Kumluca, Serik districts in Antalya province were investigated in 2016. All T. urticae populations were reared on potted cowpea (Vigna sinensis L) at 24± 1 ºC and photoperiod of 16:8h L:D. Abamectin was tested on adult females using leaf dip method (IRAC method no: 4). Bifenazate was tested on egg stage using dip method (IRAC mthod no: 3). Ranges of LC50 values in populations for abamectin and bifenazate were 5-10 and 5.1-40.0 mg(a.i.)/l, respectively. The ratios between the highest and the lowest LC50 values in populations for abamectin and bifenazate were 2 and 8 fold, respectively. LC90 values of populations for abamectin were found 152.9 to 283.6 mg(a.i.)/l. These values are more higher than that of the recommended dose of abamectin (4.5 mg(a.i.)/l). These results suggest that applications with abamectin may be result in control failures in all sampling locations. LC90 values of Kumluca1, Altınova, Gazipaşa and Aksu populations for bifenazate (73.4-134.5 mg(a.i.)/l ) were lower than that of recommended dose of bifenazate (144 mg(a.i.)/l). Bifenazate may be show high efficacy in these sampling locations, however, the efficacy of this acaricide may be low in Demre, Kumluca2 and Serik locations. Because the LC90 values of Demre, Kumluca2 and Serik populations (156.2-170.2 mg(a.i.)/l) were higher than that of the recommended dose of bifenazate. Both this study and many other previous studies related on resistance screening suggest management strategies rely on pesticides may be ineffective because of the resistant populations. IPM tools such as cultural, biological, biothecnical should be inserted in management programmes and in this way selection pressure may be decreased to mitigate the resistance problem.