Determination of resistance and resistance mechanisms to thiacloprid in Cydia pomonella L. (Lepidoptera: Tortricidae) populations collected from apple orchards in Isparta Province, Turkey

Abstract

Abstract The codling moth, Cydia pomenella is considered as the most important pest of apple worldwide and it causes significant economic losses yearly in orchards where it is not controlled effectively. The purpose of this study was to determine the resistance ratios to thiacloprid and the detoxification enzymes of Cydia pomonella from apple orchards in Isparta, Turkey. Populations of codling moth were collected from six orchards in the region and the diapausing larvae were treated with thiacloprid and chlorpyrifos by topical application. The LD50 values of field and a susceptible population were used to determine the resistance ratios to thiacloprid and chlorpyrifos. The corresponding LD50 values of C. pomonella populations showed a low (5.5–6.7 fold) or medium resistance (11.2–16.5 fold) against thiacloprid but were susceptible to chlorpyrifos. In studies conducted with synergists, piperonyl butoxide (PBO) and S,S,S, tributyl phosphorotrithioate (DEF) had a significant synergistic effect on two populations (from Gelendost and Senirkent) that medium resistance to thiacloprid. The levels of detoxifying enzymes [esterase, glutathion –S– transferase (GST) and cytochrome P450 monooxygenase (P450)] were investigated using biochemical methods and differed depending on the population. Based on the results of the enzyme analyses, the P450 and esterase enzymes may play a role in the resistance in codling moths to thiacloprid.