A new and highly effective male lure for the guava fruit fly Bactrocera correcta

Bactrocera correcta is an economically important and invasive fruit fly pest. As part of the quest to develop new chemical attractants for potential control of this species, we had previously detected a large amount of beta-caryophyllene (CAR) in the pheromone glands of wild B. correcta males. This compound was found in addition to the metabolites from consumed methyl eugenol (ME), a common male lure used for many Bactrocera species. We conducted bioassays to compare the attractiveness of CAR and ME to male B. correcta, determine the behavioural and chemo-ecological basis of the attraction and to monitor their trapping efficacy. Males of B. correcta responded strongly to CAR at a much younger age before sexual maturity compared to ME. CAR feeding increased the male mating success in comparison with lure-deprived males, and CAR-fed males were equally competitive as ME-fed males when competing for conspecific females in semi-field trials. Field trapping data also revealed that ME-baited traps captured both B. dorsalis and B. correcta, while CAR-baited traps brought in only B. correcta males. Numbers of total flies trapped per trap per day (FTD) were also significantly higher in traps baited with CAR compared to ME-baited traps, capturing up to seven times more B. correcta males. This study demonstrated that CAR is a more specific and potent male lure than ME for B. correcta. This discovery may contribute to improve the tools currently available for pest management and border biosecurity against B. correcta.