Determination of resistance levels of Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) populations to some insecticides

Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) is a significant pest that is unsuccessful in its control and causes economic losses, although many chemical control applications during the season in the Eastern Mediterranean Region of Türkiye, where citrus is grown intensively. In this study, the resistance levels of P. oleivora populations collected from Erdemli (Mersin), Karataş, Kozan, and Yüreğir (Adana) were determined to abamectin, sulfur, spirodiclofen, and pyridaben using bioassay method. The susceptible (Balcalı/Sarıçam/Adana) population was taken from the orchard without pesticide application to be used for comparison purposes in the experiments. Based on the bioassay experiments, the LC50 value of the orchard populations was divided by the LC50 of the susceptible population, the most resistant population to abamectin was found to be Kozan with 25.31 fold, and the population with the lowest resistance was determined to be Yüreğir with 8.13 fold. All populations showed low resistance against sulfur, the highest resistance rate was found in Yüreğir with 2.53 fold. The highest resistance population against spirodiclofen was detected in Erdemli with 24.00 fold, followed by Karataş, Yüreğir, and Kozan populations with 15.39, 14.05, and 9.21 fold, respectively. The resistance rates of P. oleivora populations against pyridaben were found to be 30.30, 15.85, 10.10 and 7.55 fold in Erdemli, Kozan, Yüreğir and Karataş, respectively. The populations collected from the region showed the least resistance to sulfur, and moderate resistance to abamectin, spirodiclofen, and pyridaben, and the highest resistance rate was found in the Erdemli population to pyridaben. Key Words: Acaricide, Bioassay, Eastern Mediterranean Region, Resistance, Turkey