Identifying Queensland fruit fly

Queensland fruit fly (QFF) (Bactrocera tryoni) is a serious pest that can infest many types of fruit and fruiting vegetables. It's estimated that this pest costs $300 million in control and lost market costs for horticulture across Australia.

Both residents and producers should monitor their produce for QFF and act fast to treat QFF on their property. Your support will help prevent the spread of QFF and protect Victoria's multi-million dollar fruit and vegetable industries.

Close up of an adult Queensland fruit fly with yellow markings on its back

Appearance of a Queensland fruit fly

Adult QFF are about 7mm long and are reddish-brown in colour, with distinct yellow markings.

Seasonal activity

While QFF activity usually increases in spring as the weather gets warmer, it's not strictly tied to a particular season.

If the weather stays warm enough, fruit flies can continue through their life cycle in autumn or winter as long as there's suitable host produce available.

Cluster of brown pupal cases

Signs of a Queensland fruit fly infestation

Watch this video to learn about:

  • the life cycle of Queensland fruit fly (QFF)
  • how it spreads
  • how to monitor fruit and vegetables for signs of infestation and control numbers

[Narrator]

Queensland fruit fly can be a problem for home gardeners and commercial growers because it attacks a large variety of fruit and vegetables, making them inedible. Queensland fruit fly spreads from infested plants to nearby fruit and vegetables, and by people sharing or travelling with home grown fruit or vegetables. While fruit and vegetables may look fine from the outside, they may be rotten or have eggs or maggots hidden inside.

So what do Queensland fruit flies look like? Adult flies are approximately seven millimetres long and are reddish-brown in colour, with distinct yellow markings. Queensland fruit fly goes through four main stages of life.

The adult female Queensland fruit fly injects her eggs into host fruit, laying up to 100 eggs a day. Eggs are white and one millimetre long, which makes them hard to see. You may see tiny puncture marks in fruit.

The eggs hatch into creamy yellow maggots that grow up to nine millimetres long. The maggots feed on the fruit, eventually chewing their way out. The maggots then burrow into the ground and change into oval, brown, hard pupae. After a few weeks, if conditions are suitable, the fruit flies come out of the ground and look for food around gardens.

After feeding and mating, females search for suitable ripe fruit to lay their eggs into, and their cycle continues.

So, if you want to grow fruit and vegetables in your garden, check for Queensland fruit fly and take steps to manage it before it spoils your produce or spreads to other properties.

So, to protect your garden, hang traps to monitor and catch Queensland fruit flies, apply baits and cover sprays to control Queensland fruit flies, pick up and dispose of fallen fruit, remove unwanted fruiting trees and vegetables, and net host fruit and vegetable plants.

Long white eggs inside an open piece of fruit

Before QFF become adults, they go through 3 other stages:

  1. egg
  2. maggot (larva)
  3. pupa

Signs to watch out for include:

  • eggs inside host fruits and vegetables — eggs are white, 1mm long and banana-shaped. They can be hard to see.
  • a sting on the surface of the fruit — you might also see a sting (about the size of the top of a pin) on the surface of the fruit where the adult female QFF lay the eggs
  • maggots (larva) inside fruit — maggots are 5mm to 10mm long and creamy-white in colour. They usually eat towards the centre of the fruit and cause it to rot (though the fruit might look in good condition from the outside).
  • pupa in soil — maggots burrow into the ground and change into oval, brown, hard pupae. The adult QFF will develop inside the pupa and emerge from the ground.

Monitor your produce for QFF at all stages. Catching QFF early can help prevent a serious infestation.

A rotten tomato with a fruit fly sting on the skin, shown as a halo surrounding a dark circle, and a maggot in the fruit

More information

Page last updated: 19 Aug 2020