Exotic fruit fly surveillance

Fruit flies are the world's most destructive fruit pests. The native Queensland fruit fly (Bactrocera tryoni) and the introduced Mediterranean fruit fly (Ceratitis capitata) are 2 of the most economically damaging to Australian crops.

There are many species of fruit fly that currently do not exist in Australia but could cause major disruption to our trade in horticultural products if they gained entry. Many of these are present in countries close to Australia.

The 1995 papaya fruit fly outbreak in North Queensland had a major impact on Queensland horticulture. It cost millions of dollars to eradicate the pest and for growers to meet quarantine restrictions for export. We need to be vigilant to reduce the possibility of a similar outbreak occurring again. Biosecurity Queensland maintains a network of traps throughout high-risk areas of Queensland that supports our national surveillance system.

This network also provides evidence to trading partners that Queensland is free from exotic fruit fly. Some export destinations will not import produce without this evidence.

Trapping and testing fruit flies

You should never handle or open fruit fly traps that are maintained by Biosecurity Queensland under this program.

Queensland's trapping network consists of strategically placed traps in high-risk locations. These are areas that are most likely to be infested with exotic fruit fly first if it gains entry to Queensland. High‑risk locations include urban areas associated with international ports, and remote parts of Cape York Peninsula.

Cape York Peninsula is at risk of infestation because of its proximity to Papua New Guinea, where a number of fruit flies of quarantine concern exist. These include the oriental fruit fly and melon fly. Outbreaks of these species occasionally occur on some Torres Strait Islands, where there is an ongoing fruit fly eradication program that is managed jointly between the Australian and Queensland Governments.

Trapping operations are based on national and international protocols. Lynfield lure traps are used in low rainfall areas and Steiner traps in high rainfall zones. These consist of a plastic container with openings to allow the flies to enter, with a wire hook for attaching treated cotton rolls. The traps are hung in host trees where the lure and insecticide mixture on the cotton attracts flies inside before killing them. Dead flies then collect in the bottom of the trap. Several different lure and insecticide mixtures are used in different traps to attract a wide selection of important exotic species.

There are several native fruit fly species that are abundant in Queensland. These are also caught in fruit fly traps. The differences between fruit fly species are slight and not usually evident to the untrained observer or the naked eye.

Our inspectors visit fruit fly traps fortnightly to remove any flies that are caught and send them to a central laboratory for identification. Trained volunteers visit some traps in remote areas at less frequent intervals.

Results from each week's collection are recorded in a computer database and reported to the Australian Chief Plant Protection Officer in Canberra.

If an exotic fruit fly is detected, we implement a contingency plan to limit the incursion and eradicate the species if necessary.

Learn more about identifying and detecting fruit flies and the different types of traps used.