Fruit flies

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​​​​​​​​​​​​​​​​​​​​​ The adult oriental fruit fly (bacterocera dorsalis) has prominent yellow and black markings on the thorax with wings similar length to its body.

PLANT PEST

Exotic fruit fly

Exotic to Australia

Life form: Insect
Origin: Asia
Distribution: Asia, Africa, Europe, Middle East, Pacific Islands,
​Americas
Features: Tephritids - 2.5–10 mm, colourful, pictured wings;
Drosophilidae - 2–4 mm, pale yellow to reddish brown to black
Pathways: Import of infested fruit, movement in Torres Strait
At risk: Over 300 fruit and vegetable crops


Hear more in this short video from the Chief Plant Protection Officer on Australia’s third most unwanted plant pest

Some exotic fruit fly species pose a serious threat to Australia. Many fruit flies are capable of infesting a wide range of commercial and native fruits and vegetables and causing significant damage, although the extent of infestation and damage varies among species.

There are two main types of economically important fruit fly, larger true fruit flies in the Tephritidae family, and the smaller vinegar flies in the Drosophilidae family which are sometimes also referred to as fruit flies. There are more than 150 species of native fruit fly in Australia but most of these do not attack commercial crops.

In Australia the Queensland fruit fly is of major concern but is native to Australia. Mediterranean fruit fly (Ceratitis capitata) has been introduced into Western Australia where it is subject to control and containment to stop it spreading into the eastern states. Management strategies are in place for controlling these, and other species that cause an economic impact.

The islands of Torres Strait provide a potential pathway for serious pests such as exotic fruit flies to get into Australia from countries to our north.

See if you can identify the pest

Everyone needs to keep an eye out for exotic fruit flies. The most likely way for exotic fruit flies to enter Australia is in infested fruit, or from natural movement into northern Australia through the Torres Strait.

Tephritidae and Drosophilidae are two fly families which include fruit flies.

  • Tephritids are 2.5–10 mm, often colourful with pictured wings.
  • Drosophilidae are 2–4 mm long, typically pale yellow to reddish brown to black, often with red eyes and sometimes with distinct black patterns on the wings.

Exotic fruit flies present in other countries pose high risks to our agricultural industries, including:

  • Oriental fruit fly (Bactrocera dorsalis)
  • Melon fly (Zeugodacus cucurbitae)
  • Mexican fruly fly (Anastrepha ludens)
  • Spotted wing drosophila (Drosophila suzukii).
Melon fly (Zeugodacus cucurbitae)

A microscopic view of the adult melon fly (zeugodacus cucurbitae). With a constricted waste, it is yellowish in colour with a black T shaped marking on the abdomen.
Drosophila suzukii (spotted winged drosophila), source: John Davis
Drosophila suzukii is an exotic fruit fly to Australia with distinct spots on the ends of their wings which gives the species their name. They are yellow brown flies with red eyes.

Some of these exotic species are regularly detected in the Torres Strait during the wet season, and are eradicated annually to ensure they do not move southwards, and into production areas on the mainland.

Considerable damage can occur inside the fruit before any obvious infestations are visible.

  • Discoloured patches on the skin are the most obvious signs of infestation.
  • Symptoms found on the fruit and vegetables can be very similar to those caused by native flies such as the Queensland fruit fly (Bactrocera tryoni).

Fruit flies create damage to the fruit by causing rots and discolouration.

  • Eggs are laid close to the surface inside the fruit with small discoloured patches developing as a result of the stings.
  • After hatching from the eggs, the larvae (maggots) tunnel deep into the fruit while feeding, causing considerable damage inside the fruit.
  • The affected fruit then begins to rot and often falls prematurely from the plant.
Fruit damaged by fruit flies Source: preventfruitfly.com.au
Cross sectional cut of a piece of fruit showing damaged caused by the fruit fly and larvae inside.

Any unprotected fruit will likely be damaged.

Tephritid flies can develop from eggs to adults in about four to five weeks.

  • Eggs are about 1 to 2 millimetres long, white and quickly develop into maggots which drink the rotting pulp.
  • Larvae, or maggots are creamy white and up to about 12 to 20mm long.

The difference between exotic fruit flies and native fruit flies in Australia are slight and not usually evident to the naked or untrained eye. 

More information on accurately identifying fruit flies can be found in the Australian Handbook for the Identification of Fruit Flies.

Importers

All commercial imports of fruit and vegetables are treated or are certified as being grown in fruit fly-free zones or areas. If you work around imported goods you should still be vigilant for fruit flies and unusual damage in fruit and vegetables. Evident damage may include discoloured patches and soft fruit.

Travellers

All plant products, including fresh fruit and vegetables must be declared on the Incoming Passenger Card when entering Australia. These products must be accompanied by a valid import permit or they will be destroyed. Leave any fruit on the aircraft.

When travelling throughout Australia, be aware of restrictions that may apply to the movement of fruit and vegetables to each state and territory. Check Domestic Quarantine for the latest information.

Growers and home gardeners

Fruit flies have an appetite for a wide range of fruit and vegetables. They feed on:

  • Avocado
  • Banana
  • Capsicum
  • Chilli
  • Citrus
  • Coffee
  • Grape
  • Guava
  • Mango
  • Pawpaw
  • Passionfruit
  • Tomato.

In addition to protecting your own fruit and vegetables from fruit fly damage, it is everyone’s responsibility to reduce the population of fruit flies in their local area. Fruit fly numbers usually tend to increase in spring when temperatures are warm and suitable host plants are continually available.

Growing crops prone to fruit fly attack require pest control on an ongoing basis. Check your orchards and gardens regularly for any symptoms or the presence of pests.

Check what can legally come into Australia

All Australians and international tourists have a role to keep out exotic pests and diseases. Australia remains free of many exotic fruit fly pests. We need your help to keep it this way.

Check what you can and cannot bring into Australia, whether you are a:

Allowing our fruit to fly

As well as having production impacts, these pests will have the potential to cause disruption to the export of Australian fruit and vegetables due to import restrictions by importing countries. For this reason, preventing the entry of exotic fruit flies into Australia is vital.

Import restrictions and biosecurity measures

Some items, by law, are subject to certain import conditions to be allowed into Australia. Please check the Biosecurity Import Condition System (BICON).

Be aware of any exotic fruit fly biosecurity measures that may be in place for incoming goods and conveyances. Industry advice notices are reviewed regularly and could change.

Secure any suspect specimens

Containment is critical. Fruit fly adults are active fliers. Try to locate the source of the infestation and secure the fruit by it sealing in a plastic bag.

Do not move infested fruit or vegetables from the orchard or your yard.

Report detections of exotic pests

Any detections of exotic fruit flies must be reported to the authorities. Report any imported fruit with maggots.

Import community and travellers

If you receive or work around goods imported from overseas, including mail, you need to be vigilant to exotic fruit flies and other exotic pests. If you see an unusual pest or damaged fruit with internal maggots, secure the goods to limit the movement of the pest and immediately report it to the Department of Agriculture and Water Resources SEE. SECURE. REPORT. Hotline on 1800 798 636 or by using the online form.

Growers and home gardeners

If you see any exotic fruit flies and/or damaged fruit or anything unusual, report it to the Exotic Plant Pest Hotline1800 084 881. This will put you in touch with the department of primary industries or agriculture in your state or territory.

When reporting your concern, you will be given advice on handling the specimen and what to do next until an officer can investigate.

Additional information

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