Queensland fruit fly







Bactrocera tryoni


The adults have brown bodies with yellow markings and look a bit like wasps. They hold their wings horizontally out from their bodies when stationary or walking. The larvae are small pale yellow maggots. These have the ability to “jump”. They bring their hindquarters up to towards their head, like a looper caterpillar, then they spring off the surface.

Adult size: 6-8 mm

Out and about

They like the warmer, humid conditions and are most numerous from mid spring to early autumn ( tropical wet season) and when plants are producing fruit. Their numbers decrease over winter and adults will shelter and survive, but if the weather remains warm and there is still fruit happening, they will continue to be around. They are active in the early morning and late evening. They are native to Australia. As the name suggests they were mainly in Queensland but they are progressing further south into temperate regions.

Reproduction and Life cycle

The tiny (1 mm) eggs are white and crescent-shaped, hatching into pale cream maggots (6-8 mm). The maggots become more yellow as they develop, finally emerging and dropping onto the ground where they pupate in the soil. In ideal conditions the life cycle of one generation can be completed in 4 weeks. The female can lay up to 100 eggs a day equating to hundreds of eggs in her lifetime. They live for many weeks, feeding on honeydew and nectar.

To deter

- Cover fruit to prevent fruit flies from laying eggs

To control

- Spinosad is a naturally occurring bacterium which disrupts their nervous system causing a quick death. There is a product available that contains spinosad with fruit fly pheromones added to it so that it attracts and targets only fruit flies. Apply to something near the plant (such as stakes) at intervals of a few metres. It is not necessary to apply it on the plant or the fruit for it to work. - Commercial traps are available which lure the male fruit fly. They can be used as an indicator of the presence of fruit flies - Clean up ALL rotted and rotting fruit and place in a black plastic bag or in the freezer for a few days to kill them. DO NOT ADD TO COMPOST.

Plants to repel

Basil (plant with tomatoes) / Lad’s love and other plants that repel flies may help

Plants to attract


Why they are a Pest
The female fly lays her eggs in a wide range of fruits. The eggs hatch into maggots that feed on the fruit as they develop, causing it to rot from the inside. They have a bacteria which breaks down the fruit making it easier for them to digest. Evidence of fruit having been stung is visible as small brown marks that may be raised lumps. They will lay eggs in virtually any fruit including apple, apricot, avocado, capsicum, cherry, citrus, custard apple, grape, guava, kiwifruit, mango nectarine, papaya, passionfruit, peach, pear, persimmon, plum, pomegranate, quince, poquat, tamarillo, tomato and probably every other tropical fruit.