Detection and geographical distribution of the organophosphate resistance-associated Delta 3Q ace mutation in the olive fruit fly, Bactrocera oleae (Rossi)

Abstract

BACKGROUND The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is the most important pest of olives. Its control is based mostly on organophosphate (OP) insecticides, a practice that has led to resistance development. OP resistance in B. oleae has been associated with three mutations in the acetylcholinesterase (AChE), the product of ace gene. The current study presents new diagnostic tests for the detection of the ace mutations and aims at monitoring the frequency of the Delta 3Q mutation, which appears associated with resistance at higher OP doses in natural olive fly populations. RESULTS An allele-specific polymerase chain reaction (PCR), a PCR-RFLP (restriction fragment length polymorphism) and a Taq-Man test were developed for the Delta 3Q mutation detection and a new duplex quantitative PCR assay was designed for the G488S and I214V mutations. Moreover, the frequency of Delta 3Q mutation was examined in ten populations of eight countries around the Mediterranean basin. The highest frequencies (10%) were found in Greece and Italy, whereas a gradual decrease of Delta 3Q frequency towards the western Mediterranean was noted. CONCLUSION Robust tests for insecticide resistance mutations at their incipient levels are essential tools to monitor the increase and geographical spread of such mutations. Three different tests were developed for AChE-Delta 3Q that indicated its association with OP applications across the Mediterranean. (c) 2013 Society of Chemical Industry