Queensland Fruit Fly

(Bactrocera tryoni)

Queensland Fruit Fly was found in metropolitan Melbourne in January 2008. This is a matter of very great concern. Queensland Fruit Fly is a very serious pest of great economic significance because of the damage caused to the fruit industry. It may affect the home gardener who grows fruit and vegetables as well as the horticulture industries.

Plant Health Australia (PHA) is currently facilitating a major national initiative to improve the management and eradication of fruit fly. Those who live in an infected area should do all they can to eliminate this pest. This means caring for your fruit trees and disposing of all fruit correctly.

Inspect Regularly

Home grown fruit should be inspected on a regular basis for the presence of fruit fly larvae. The larvae may be easier to find than the adult fruit fly.

The adult fruit fly has a wasp like appearance. It is about 7 mm long. It is a reddish brown colour with yellow oval markings. The female fly lays eggs in the ripening fruit and the larvae burrows inside the fruit and so destroys it.

Most fruits can be affected including peaches, oranges, apples, pears, tomatoes and capsicums. There are traps which can be used to detect the presence of fruit fly. Some fruit, such as banana and avocado may be picked in a mature green condition, before fruit fly can lay its eggs in the fruit.


If you grow any fruit trees they should be pruned regularly to a height that the fruit can be picked. Ripe fruit should be removed from the tree before it falls to the ground. Any fruit which does fall to the ground should be collected immediately and sealed in a plastic bag. The sealed bag should be left in the sun for 3-7 days so that the heat will kill the larvae and prevent them developing into fruit fly adults.

There are chemicals which can be used to prevent infestations or control fruit fly but there are also other methods, such as traps which attract the flies with a pheromone and then kill them with an insecticide.

Chooks to the Rescue!

Poultry are an enormous help in fruit fly control. If you design your orchard to incorporate chooks they will reward you by turning rotten fruit into eggs and happily spend hours scratching beneath trees looking for fruit fly pupae. Adult fruit flies are trapped on the ground for up to 24 hours after emerging from the pupae as it takes this long for their wings to harden. During this time the adult flies are also vulnerable to a roving chook. Where it isn’t possible to allow chooks free range, small demountable fences can be used under trees vulnerable to attack by fruit fly.

If you find maggots they need to be accurately identified so that a method of eradication can be established. Contact your local Department of Primary Industry if you find maggots.

Exclusion Zones

Major fruit production areas such as the Sunraysia and the Riverland are in an area known as the Fruit Fly Exclusion Zone. This area was established to facilitate exports of their produce to both other areas of Australia and overseas. There are roadside bins for travellers to deposit any fruit before entering these areas. There is fruit fly in eastern Victoria and fruit may not be removed from this area.

Host Plant

Clivia sp. have been found to be a host for fruit fly. Fruit fly lay maggots in the developing fruit, so spent flower heads should be removed.

Interestingly, horticulture students doing research accidentally discovered this connection!

Contacts for State Government Departments:
Victoria 136 186, or free call 1800 084 881
NSW www.dpi.nsw.gov.au
Queensland www.qld gov.au, 132 523
SA www.pir.sa.gov.au/biosecurity/plant_health, 1300 666 010
WA www.agric.wa.gov.au

Image sources::
Top image courtesy of Rural City of Wangaratta
Second image courtesy of Department of Agriculture & Food WA
Trap image courtesy of www.greenharvest.com.au

Banner image: James Niland – Flickr: Queensland Fruit Fly – Bactrocera tryoni, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=14743812