Mediterranean fruit fly
The Mediterranean fruit fly (Ceratitis capitata), or medfly, is a significant horticultural pest that is established in parts of Western Australia.
Medfly attacks a wide range of fruits and fruiting vegetables, decreasing production and making fruit inedible. This can have severe consequences for local and international trade.
Appearance of a medfly
Adult medfly are 3 to 5 millimetres long and yellowish in colour. They have black markings on the body and distinctive brown bands on the wings.
There are 4 stages in the life cycle of medfly:
- maggot (larva)
- adult fly
Eggs are laid in host fruit and are white in colour and banana-shaped. They're usually too small to see and are rarely identified by gardeners.
- Soon after the eggs have been laid by the female, a small maggot emerges from each egg.
- Maggots have cutting jaws that help to tear the fruit into pieces small enough to swallow. Maggots tend to eat towards the centre of fruit. This promotes rotting of the fruit, although it may appear 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.
In the soil, the maggot becomes inactive and changes into an oval, brown, hard pupa.
- The adult medfly hatches and emerges from the ground.
- After feeding and mating, females search for suitable ripe fruit to deposit their eggs. The punctures ('stings') made by laying females in the skin of fruits are very small and usually can only be recognised by an experienced person.
Adult medfly can live for 2 to 3 months.
Surveillance and prevention in Victoria
Monitoring for medfly activity in Victoria
Adult medfly activity can be monitored by using traps. The most commonly used attractant is Capilure, which contains a synthetic attractant that lures male flies.
Traps are usually placed in the shade of the canopy of host trees, and the contents checked regularly throughout the year.
Control and eradication
If medfly is detected, we can declare an outbreak and undertake control activities, including:
- preventing the movement of fruit from the area
- removing fruit from plants
- destroying wild or neglected fruit trees
Eradication measures include cover sprays and bait sprays. Cover sprays are generally systemic insecticides that will also kill maggots present in fruit. Bait sprays, which are a mixture of protein, water and an insecticide, can be spot sprayed onto various sites in an orchard. If the outbreak is in an urban area, every property within a specified zone may be sprayed with bait to control the population of adult flies.
Quarantine measures such as inspection and treatment of fruit and vegetables assist in preventing the entry of medfly into Victoria.