Appearance and life cycle
Queensland fruit fly (Bactrocera tryoni), or QFF, is a significant horticultural pest which permanently inhabits parts of the Northern Territory, Queensland, New South Wales and some parts of Victoria.
QFF attacks a wide range of host plants, decreasing production and making fruit inedible. This can have severe consequences for local and international trade.
Queensland fruit fly host fruit and fruit vegetables cannot be transported to QFF sensitive markets, including the Greater Sunraysia Pest Free Area (PFA), without certification. For more information about certification arrangements, visit the domestic market access webpage.
Adult QFF are about seven millimetres long and are reddish-brown in colour, with distinct yellow markings.
While QFF activity generally increases in spring as the weather gets warmer, it is not strictly tied to a particular season. If sufficiently warm weather persists into autumn or winter, fruit flies can continue through their life cycle providing that a suitable host fruit or fruiting vegetable is available.
There are four stages in the life cycle of Queensland fruit fly: egg, maggot (larva), pupa and adult fly.
1. Egg – Eggs, which are laid in host fruit, are white in colour and banana-shaped. They are unlikely to be seen by gardeners.
Abdomen and eggs of Queensland fruit fly
2. Maggot (larva) - Soon after the eggs have been laid by the female, a small maggot emerges from each egg. Maggots have cutting jaws which help to tear the fruit into pieces small enough to swallow. Maggots tend to eat towards the centre of the fruit. This promotes rotting of the fruit, although it may appear to be in good condition from the outside. When the maggot has completed growing, it chews its way out of the fruit - which by then has usually fallen to the ground - and burrows into the soil.
Peach infested with Queensland fruit fly larvae
3. Pupa - In the soil, the maggot becomes inactive and changes into an oval, brown, hard pupa.
Queensland fruit fly pupae
4. Adult fly - The adult Queensland fruit fly hatches and emerges from the ground. After feeding and mating, females search for suitable ripe fruit to deposit their eggs. The punctures ('stings') are very small and usually can only be recognised by an experienced person.
Female Queensland fruit fly preparing to lay eggs