Mediterranean Fruit Fly

About Mediterranean fruit fly

Fruit flies are widely recognised as the world's worst economic pest of fruit. Apart from lowering production and making fruit inedible, their presence has severe consequences on trade to sensitive markets, both locally and internationally.
Only two species of economically important fruit flies occur in Australia. One is the Mediterranean fruit fly, which is endemic to parts of Western Australia, and the other is Queensland fruit fly.

The lifecycle of Mediterranean fruit fly

As with most insects, there are four stages in the life cycle: egg, maggot (larva), pupa and the adult fly.

• Egg - eggs are white in colour and banana-shaped. They are seldom identified by householders.
• Maggot (larva) - soon after the eggs have been laid within the fruit, they hatch and a small maggot emerges from each. It has cutting jaws which help it to tear off small pieces of the fruit. As maggots tend to eat their way towards the centre of fruit, decay begins inside. However, from the outside the fruit may appear undamaged. As the maggot completes its growth, it chews its way out of the fruit (which by then has usually fallen) and burrows several centimetres into the soil.
• Pupa - in the soil, the maggot becomes inactive and changes into an oval, brown, hard pupa.
• Fly - the fly develops within the pupa and then bursts open the pupal case, before seeking out a food source. After feeding, mating occurs and then females search for ripening fruit. Eggs are laid in the fruit through a puncture hole made in the skin. The punctures are very small and can only be recognised by an experienced person.

Surveillance and prevention program in Victoria

Monitoring and control

Adult fruit fly activity can be monitored by using traps containing synthetic male attractants. The most commonly used attractant is capilure, which only attracts the male flies. Traps are placed in the shade of the canopy of host trees and the contents checked regularly through the year.

If fruit fly is detected, an outbreak may be declared and control and eradication activities undertaken. Control measures include preventing the movement of fruit from the area, removal of fruit from plants and destruction of wild or neglected fruit trees.

Eradication measures include treatments using cover sprays and bait sprays. Cover sprays are generally systemic insecticides that will also kill immature stages 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.

Prevention

Quarantine measures such as inspection and treatment of fruit and vegetables assist in preventing the entry of Mediterranean fruit fly into Victoria.

High risk materials

The host list for the Mediterranean fruit fly highlights that it affects a wide range of fruit and fruiting vegetables.

What to do if you suspect you may have Mediterranean fruit fly on your property

If you think that you have found Mediterranean fruit fly, contact DPI on 136 186.

Alternatively, you can email us at plant.standards@dpi.vic.gov.au.