Oriental fruit fly

Have you seen Oriental fruit fly symptoms?

In Queensland, Oriental fruit fly (Bactrocera dorsalis) is listed as prohibited matter under the Biosecurity Act 2014.

Be on the lookout for these symptoms and report them to Biosecurity Queensland.

Early detection and reporting of symptoms are the key elements in controlling the pest.

Call us  13 25 23

  • Picture of an Oriental fruit fly
    Picture of an Oriental fruit fly

General information

It is important to let us know as soon as you suspect Oriental fruit fly so that it can be eradicated before it becomes too widespread.

It has been found that 4 pest species B. dorsalis, B. papayae, B. philippinensis and B. invadens are the same species and are all now known as B. dorsalis, the Oriental fruit fly.

Overview

Other name

Bactrocera papaya, Bactrocera dorsalis (Hendel), papaya fruit fly, Bactrocera philippinensis, Bactrocera invadens

Description

Appearance

  • About the same length as a common housefly but more slender.
  • Similar to a small wasp. 
  • Adults are about 7 mm in length. 
  • Clear wings.
  • Generally has a black chest and a paler abdomen with a distinctive black T-shaped marking on the back.

Similar species

The Queensland fruit fly is a similar size but a reddish-brown colour. An expert eye is needed to identify Oriental fruit fly under a microscope.

Distribution

Oriental fruit fly is a serious pest worldwide. It is widespread in southern Asia, Taiwan, Hawaii, Tahiti, Mariana Islands and Africa.

This species is well established in Papua New Guinea and has been detected several times in the islands of Torres Strait. It has not established a presence as any detection is immediately eradicated under the Torres Strait Exotic Fruit Fly Containment Program.

Oriental fruit fly is endemic in southeast and southern Asia and has spread to Hawaii, Tahiti, Mariana Islands and Africa. It has been present in Papua New Guinea since 1992. In March 1993, it was detected for the first time in Australian territory on the islands of Saibai, Boigu and Dauan, adjacent to the Papua New Guinea coast; and on Stephen and Darnley Islands close to the centre of Torres Strait and was subsequently eradicated.

Crops affected

This pest infests over 300 fruit and vegetable types including mango, banana, papaw, coffee, citrus, guava, passionfruit, tomatoes, chilli and capsicum. Many of these are affected at a greener stage.

Life cycle
  • Adult female flies lay their eggs just under the skin of fruit and deposit fruit decaying bacteria.
  • Within 1-2 days, the eggs hatch into larvae (maggots) which feed on the decaying fruit, causing premature fruit drop.
  • After 7-12 days the larvae drop from the fruit to develop into pupae in the soil.
  • Adults emerge after another 10-14 days. The adults become sexually mature after 1-2 weeks.
  • They live for several months and are capable of reproducing throughout their life span.
Symptoms

As with other fruit fly species, females 'sting' the fruit when they lay their eggs inside. Larvae tunnel into the fruit and considerable damage can occur inside the flesh before obvious signs can be seen on the fruit. The most obvious signs of infestation are:

  • small discoloured patches on the skin, which develop from the stings
  • affected fruit will rot and often fall from the plant prematurely.
Impacts

Oriental fruit fly is the most damaging pest of tropical horticulture in the world because of its wide host range and ability to attack some fruit green. It could easily be brought into Australia by illegal imports of fruit. Costly quarantine restrictions and eradication measures would be required if it established in Queensland.

It would also have serious consequences for our horticultural industries. Many countries have trade restrictions on fruit that come from regions known to have Oriental fruit fly. Growers would likely have difficulties exporting their produce.

In 1995 Oriental fruit fly established near Cairns and cost $33.5 million and took 4 years to eradicate.

Spread Like most tropical fruit fly species, Oriental fruit fly multiplies rapidly and can spread over large distances. It is capable of establishing in any of the mainland states of Australia.
Risk period Oriental fruit fly moves into the Torres Strait with the monsoonal winds each wet season (over summer) and is eradicated annually as part of a proactive containment strategy by the Queensland and Australian Governments.
Monitoring and action

If you notice unusual damage in fruit or vegetables, e.g. they are getting stung at a hard green stage then contact us. There are several native pest species of fruit fly that will also damage fruit but usually when it is ripe.

Ongoing monitoring by government

Queensland Government monitors a network of traps for Oriental fruit fly/papaya fruit fly in high-urban areas and remote centres in Queensland.

Australian Government surveys each inhabited island in Torres Strait. Biosecurity Queensland acts quickly with well planned eradication strategies whenever Oriental fruit fly/papaya fruit fly is detected on Queensland territory.

ControlEarlier applications of spray regimes and more intensive or regular treatments will be required in some crops.
Quarantine restrictionsShould an incursion of this pest occur the Australian and Queensland government would likely impose quarantine restrictions on affected areas, increase trapping to determine the extent of the affected area and implement eradication methods to kill any Oriental fruit flies detected.

Last updated 19 February 2015