Maintaining Tasmania’s freedom from fruit fly: A strategy for the future 2017-2050
Tasmanian fruit producers’ continued access to premium export markets is now being further supported by this long-term fruit fly strategy. Facing challenges posed by projected climate change accompanied by changes to tourism and to export and import volumes, the strategy identifies a number of key areas for future action.
This important strategy was launched in June 2017.
Find out more about the fruit fly strategy.
In 2011, Tasmania's Import Requirements for fruit fly host produce were reviewed. The review included stakeholder and public consultation.
The final report of that review has now been published.
What are fruit flies?
Fruit Fly image
Fruit flies cause enormous damage to fruit and some vegetable crops around the world. They are unlikely to cause the same damage in Tasmania, but their mere pesence at low levels impeded export trade. Tasmania is free of fruit fly and it is important for our horticultural industries that we keep fruit fly out of the state.
There are around 14 species of fruit fly of potential economic concern on the Australian mainland. The two that pose the most risk to Tasmania are:
Queensland fruit fly along the eastern seaboard and in the Northern Territory
- the Mediterranean fruit fly in Western Australia.
Why keep fruit fly out of Tasmania?
Tasmania has a reputation, both nationally and internationally, as a reliable producer of the best fruit and vegetable products. Our freedom from a wide range of serious pests and diseases gives our producers a significant competitive advantage in the key markets. Indeed our access to the premium markets in Japan, Korea, USA, Taiwan and China is dependent on our fruit fly free status.
The cost of fruit fly to producers where it exists on the mainland is substantial. That cost includes:
- loss of product due to infestation
- restricted market access for any "clean" product from within a biosecurity area (typically 15 km radius of an infested property)
- the costs of an eradication program (typically baiting)
- the costs of ongoing insecticide use
- the loss of any market premium that goes with not having to fumigate export fruit.
It is estimated our fruit fly free status adds several million dollars a year to the export income earned by Tasmania's horticultural industries.
What types of fruit and vegetable are susceptible?
Stone and pome fruits are especially susceptible. Citrus, fig, and many tropical fruits are also susceptible as are fruiting vegetables such as tomato, eggplant and capsicum. Some native and ornamental fruits are susceptible as well.
See below for a more comprehensive list
Do Tasmanians have legal responsibilities in relation to fruit fly?
Yes. And the law applies not only to orchardists but also to anyone with a home garden, crops that are hosts to fruit fly such as tomatoes etc or a small acreage that is not farmed commercially.
Fruit fly is declared as a List A pest under the Plant Quarantine Act 1997. People are required by law to report promptly any signs of fruit fly on their property. If you see anything suspicious on your property, you should call the Hobart Biosecurity Operations Centre on 1800 084 881 without delay.
There are also legal restrictions on people
bringing fruit and vegetables into Tasmania
. In short, people are not allowed to bring fruit or vegetables with them when they come to, or return to, Tasmania. Biosecurity Tasmania ensures everyone coming into Tasmania is fully aware that they may not bring fruit or vegetables with them - and prosecutes those who fail to comply.
Commercial shipments of some types of fruit and vegetables are allowed if and only if they comply with Biosecurity Tasmania's strict biosecurity requirements (see
Plant Biosecurity Manual
for import requirements). All fruit and vegetables require special certification from the State of Origin. Most imported fruit is certified by fumigation.
How could fruit fly be introduced into Tasmania?
By far the most likely way is as maggots or eggs in fruit and susceptible vegetables. That is why Biosecurity Tasmania is so rigorous in policing the ban on tourists, interstate home gardeners and returning Tasmanians from bringing fruit and vegetables into the state.
It is possible, but unlikely, that mature fruit flies could be brought across Bass Strait on the ferry or by plane.
The distance across Bass Strait is such that mature fruit flies being blown over from the mainland is considered highly unlikely.
What do fruit flies look like?
A mature fruit fly is around 7mm long and is reddish brown with some yellow markings (see image above).
Fruitfly larvae courtesy of NSW DPI
Fruit fly larvae look like blowfly maggots. Mature larvae are 8-11mm in length and 1.2-1.5mm in width. They are usually easy to see in the flesh of the fruit. You are more likely to see fruit fly grubs or maggots
than actual flies. If you see anything that looks like this in your fruit (either
bought in fruit or fruit on trees in your backyard), please report it
straightaway DPIPWE on 1800 084 881.
A key sign of fruit fly is a series of "stings" visible on the outside of the fruit. A "sting" is a puncture mark caused when a female adult lays eggs into the fruit. If you open up the "sting" carefully with a sharp knife, you should see a cavity containing eggs or the debris of hatched eggs - you would probably need a magnifying glass to see it.
Does Tasmania have a fruit fly surveillance program?
Yes. There is a
network of around 900 fruit fly traps at various risk points from Dover to Smithton. These pest surveys are ongoing to prove that Tasmania is fruit fly free. These surveys are also intended to give Biosecurity Tasmania an early warning of a fruit fly incursion.
A special message for home gardeners and block owners
Where there are fruit fly affected areas on the mainland, fruit fly populations are generally a lot higher in urban home gardens and small blocks than in outlying orchards. In a fruit fly outbreak, lone fruit trees or vines in an urban backyard and neglected fruit trees or vines on non-commercial smallholdings are a major biosecurity risk. This is especially so if the owner fails to collect and destroy fallen fruit.
If there were an outbreak of fruit fly in Tasmania, would this pest establish here in Tasmania?
For many years, the belief has been that fruit fly would not survive a Tasmanian winter. However, even a temporary summer population of the pest could disrupt fruit exports. Any degree of trade disruption is undesirable for our growers.
How can the public help?
Public assistance is a vital part of our ongoing surveillance for any signs of fruit fly. The most useful thing you can do is to keep a keen eye out for any signs of fruit fly. The most likely sign you might see is larvae (i.e. grubs) in a piece of fruit - either fruit you have bought or fruit in your backyard. They look similar to blowfly maggots. If you do see what you think may be signs of fruit fly, contact DPIPWE's 24 hour/ 7 day
1800 084 881
number immediately. If you are not sure, please report anyway. There are no costs involved in reporting and you would be performing an important public duty in alerting us to anything that might be fruit fly.
Whatever you do, do NOT dispose of any fruit that has a grub you think might be fruit fly. You would be given instructions on what to do when you report to the DPIPWE
1800 084 881
number. In most cases, you would be asked to place it in a plastic bag or plastic container and put it in your fridge until a Biosecurity Tasmania officer collects it.
Are fruit flies attracted to over-ripe fruit on trees, fallen fruit, or discarded fruit in piles, pits or compost heaps?
Female fruit flies lay eggs in maturing and ripe fruit on the tree. The skin of the fruit needs to be soft enough for the fly to pierce the skin with her ovipositor. Lesions in damaged fruit can also facilitate egg-laying. The larvae (maggots) tunnel into the fruit causing rotting, and so infected fruit often falls to the ground prematurely. Maggots continue to develop in fallen fruit. Infected fruit must not be disposed of in compost heaps.
How many grubs would we expect in a single piece of infected fruit (i.e. if this is from one infected piece of fruit how many flies could there be)?
The number of grubs in a single piece of fruit varies from as little as 1 to more than 60, however typically we would expect to find 4-20 grubs in each piece of infected fruit.
What fruit is capable of harbouring fruit fly?
The fruits grown commonly in Tasmania that could be attacked by fruit fly include:
However, a wide range of other fruits, not commonly grown here or that are only imported from warmer climates are also capable of harbouring fruit fly. For a complete list of host plants, see below.
Anacardium occidentale (cashew nut), Annona glabra (pond apple), Annona muricata (soursop), Annona reticulata (bullock's heart), Averrhoa carambola (carambola), Capsicum annuum (bell pepper), Carica papaya (papaw), Casimiroa edulis (white sapote), Chrysophyllum cainito (caimito), Coffea arabica (arabica coffee), Eriobotrya japonica (loquat), Eugenia uniflora (surinam cherry), Fortunella japonica (round kumquat), Lycopersicon esculentum (tomato), Malus sylvestris (crab-apple tree), Mangifera indica (mango), Manilkara zapota (sapodilla), Morus nigra (black mulberry), Passiflora edulis (passionfruit), Passiflora suberosa (Corky passionflower), Prunus persica (peach), Psidium cattleianum (strawberry guava), Psidium guajava (guava), Syzygium aqueum (watery rose-apple), Syzygium jambos (rose apple), Syzygium malaccense (malay-apple), Terminalia catappa (Singapore almond)Minor Hosts
Aegle marmelos (golden apple), Annona squamosa (sugarapple), Averrhoa bilimbi (blimbe), Blighia sapida (Akee apple), Calophyllum inophyllum (Alexandrian laurel), Cananga odorata (perfume tree), Citrus aurantiifolia (lime), Citrus aurantium (sour orange), Citrus jambhiri (rough lemon), Citrus limetta (sweet lemon tree), Citrus limon (lemon), Citrus maxima (pummelo), Citrus medica (citron), Citrus reticulata (mandarin), Citrus sinensis (navel orange), Citrus x paradisi (grapefruit), Clausena lansium (wampi), Cucurbita moschata (pumpkin), Cydonia oblonga (quince), Cyphomandra betacea (tree tomato), Dimocarpus longan (longan tree), Diospyros blancoi (mabolo), Diospyros kaki (persimmon), Dovyalis caffra (kei apple), Eremocitrus glauca (Australian desert lime), Eugenia dombeyi (brazil cherry), Feijoa sellowiana (Horn of plenty), Ficus racemosa (cluster tree), Flacourtia jangomas (Indian plum), Flacourtia rukam (rukam), Fortunella x crassifolia (meiwa kumquat), Grewia asiatica (phalsa), Juglans regia (walnut), Litchi chinensis (lichi), Malpighia emarginata, Mimusops elengi (spanish cherry), Momordica charantia (bitter gourd), Morus alba (mora), Musa x paradisiaca (plantain), Myrciaria cauliflora (jaboticaba), Nephelium lappaceum (rambutan), Nerium oleander (oleander), Olea europaea subsp. europaea (olive), Opuntia ficus-indica (prickly pear), Passiflora foetida (red fruit passion flower), Passiflora quadrangularis (giant granadilla), Persea americana (avocado), Phoenix dactylifera (date-palm), Phyllanthus acidus (star gooseberry), Physalis peruviana (cape gooseberry), Pometia pinnata (fijian longan), Pouteria caimito, Pouteria campechiana (canistel), Pouteria sapota (mammey sapote), Prunus armeniaca (apricot), Prunus avium (sweet cherry), Prunus cerasifera (myrobalan plum), Prunus domestica (plum), Prunus salicina (Japanese plum), Psidium guineense (Guinea guava), Punica granatum (pomegranate), Pyrus communis (European pear), Rollinia mucosa, Rollinia pulchrinervis, Rubus fruticosus (blackberry), Rubus ursinus (boysenberry), Solanum laciniatum (kangaroo apple), Solanum melongena (aubergine), Solanum seaforthianum (star potato-vine), Solanum torvum (turkey berry), Spondias mombin (hog plum), Spondias purpurea (red mombin), Synsepalum dulcificum, Syzygium cumini (black plum), Syzygium paniculatum (Australian brush-cherry), Syzygium samarangense (water apple), Thevetia peruviana (exile tree), Trichosanthes cucumerina var. anguinea (snakegourd), Vitis labrusca (fox grape), Vitis vinifera (grapevine), Ziziphus mauritiana (jujube).
If you see what you think might be fruit fly grubs in any fruit, please contact us anyway (1800 084 881