Australia is fortunate to be free of many of the fruit fly species that occur in other parts of the world. Exotic species such as the oriental fruit fly, melon fly, Mexican fruit fly, and Natal fruit fly could devastate Australian horticulture if they were to arrive in Australia, establish and spread. Governments and industries invest heavily on ensure Australia remains free of exotic fruit flies.
The potential impact is well known. In 1995, Asian papaya fruit fly was detected near Cairns, Queensland. Following this detection, governments an industries spent $36m to eradicate this species, while industries also sufferred and estimated $100m impact due to additional quarantine treatments and lost trade opportunities. At the time it was thought that the Asian papaya fruit fly was a pest that only affected a small number of tropical hosts, but recent research has determined that in fact four species that were once considered to be separate are in fact the same. Therefore, Asian papaya fruit fly is now known as the oriental fruit fly and it is know it has a much wider host range. If it were to establish in Australia, many of our horticultural industries would be threatened.
There are a number of ways that exotic fruit flies could reach Australia. The most obvious of these is for fruit flies to be transported with fruits or vegetables coming to Australia. However, Australia has in place a stringent biosecurity system and requires commercially imported fruits and vegetables to be assessed for risks and for approved fruit fly treatments to be applied when necessary. Private and business travellers could also bring fruits and vegetables to Australia in checked baggage or hand-luggage, but again Australia’s biosecurity system works to address this risk though a combination of public awareness, incoming passenger declarations, and inspections at the border.Learn more about Australia's biosecurity system (agriculture.gov.au) Learn more about import conditions (agriculture.gov.au)
Australia’s geographical isolation means that it is unlikely for fruit flies to directly enter Australia through natural spread – they simply cannot fly far enough. However, the main exception to this is the relatively narrow stretch of water separating Australia’s Cape York Peninsula from Papua New Guinea. This area, Torres Strait, is just 150km across and is populated by numerous islands. A combination of strong seasonal winds and human assisted movement could assist exotic fruit flies spread to Australia. The numerous islands in Torres Strait would also assist fruit flies to establish and progressively “island hop” all the way to Australia.
To address this risk, the Australian Government and Queensland government operate an extensive detection and response system in Torres Strait and which is designed to detect and eradicate any fruit fly populations before they can reach Australia. This Long-term Containment Strategy for Exotic Fruit Flies in the Torres Strait involves the deployment of fruit fly monitoring traps, and the application of protein bait sprays and male annihilation blocks. Across the north of Australia, the Northern Australia Quarantine Strategy also has fruit fly monitoring arrangements and restrictions on the movement of fruits and vegetables and other materials that could pose a biosecurity risk.
While many of the fruit flies exotic to Australia are very different to those that occur within Australia, some also look very similar. The oriental fruit fly and other species that occur to the north of Australia appear almost identical to the Queensland fruit fly and some other species that occur in Australia and it often requires a skilled entomologist to accurately distinguish them apart. Therefore, if you observe symptoms of fruit flies that are unusual, more damaging than you have seen before, or in crops that have not previously been affected, whether they occur at home or in a commercial setting, you should report these to the Exotic Plant Pest Hotline on 1800 084 881.
Should you receive imported goods, or work with imported products, you can help maintain Australia’s freedom from exotic fruit flies and other pests. If you see fruit with maggots or any unusual pests, secure the goods and report it immediately to the Department of Agriculture and Water Resources via the SEE. SECURE. REPORT. Hotline on 1800 798 636.
Below is a short video from Australia’s Chief Plant Protection Officer on the threat posed by exotic fruit flies.