eva‎luation of resistance to respiratory inhibitor acaricides in the populations of European red mite Panonychus ulmi Razieh Yaghoobi r yaghoobi@ag iut ac ir January 2020 Department of Plant Protection Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Jahangir Khajehali Khajeali@iut ac irAbstractThe European red mite Panonychus ulmi Koch is one of the most important pests in appleorchards of Iran as well as the world Fenpyroximate is one of the most common acaricide whichhas been extensively used against this pest The Mitochondrial Electron Transport Inhibitors METI s at complex I has been the well known target site of fenpyroximate To eva‎luatefenpyroximate resistance in field collected populations of P ulmi 11 populations were collectedfrom commercial apple orchards of East Azarbaijan West Azarbaijan and Isfahan provinces andone population of Belgium The fenpyroximate toxicity was determined using a Potter spraytower The LC50 values ranged from 121 8 to 5713 9 mg a i L 1 Orumih population was foundas the susceptible and padena deverajan was detected as the most resistant populationrespectively Synergistic assays using Piperonyl butoxide PBO a cytochrome P450monooxygenase inhibitor significantly increased fenpyroximate toxicity in the PSR TKpopulation which a synergistic ratio SR of 6 72 fold Also pretreatment withtriphenylphosphate TPP resulted in reduced LC50 values of fenpyroximate in Shahin Dej SR 6 07 fold and PSR TK SR 2 68 fold populations Cross resistance assay was performed usingPSR TK and Shahin Dej populations against pyridaben and cyflumetofen and the resultssuggested that fenpyroximate resistant populations are also resistant to pyridaben In addition tosynergism assays to determine the role of detoxification enzymes in resistance development theactivities of these enzymes were also eva‎luated The esterase activity was estimated 2 24 foldhigher in the resistant population of Shahin Dej Furthermore the activity of glutathione S transferases GSTs in the Shahin Dej population showed 1 15 fold higher activity in susceptiblepopulations and activity P450s were revealed significant differences between population resistantand susceptible A PSST subunit of complex I fragment harboring two previously knownmutations H92R and A94V which have been linked to METI I resistance was amplified andsequenced Furthermore a PCR RFLP assay using enzyme TseI was used to determine thefrequency of A94V mutation The results of both sequencing and PCR RFLP showed that noneof the mutations are possibly involved in fenpyroximate resistance in tested populations Overall in the present study relatively moderate to high levels of resistance to fenpyroximate were foundin P ulmi populations and the resistance could be related to the enhanced detoxification Theresult provides useful information in the early detection and management of fenpyroximateresistance in P ulmi Key Words Fenpyroximate Detoxification Enzymes Target site mutations METI I 55

جهانگير خواجه علي

نفيسه پورجواد

رحيم مهرابي- لادن طلايي