Strathbogie Shire Council

Tel 24/7: 1800 065 993

Queensland Fruit Fly

There are over 200 species of fruit fly in Australia.

However, only two of them - the Queensland Fruit Fly on the east coast and the Mediterranean fly on the west coast - are problems for gardeners and agri-business, costing over $487 million in the Goulburn Murray region alone.

Both species have similar host plants, including citrus, loquats, stone fruits, apples, pears, avocados, bananas, mangoes, guavas, feijoas, tomatoes, eggplants and capsicum.

There are more than 100 commonly cultivated crops that fruit fly will infest.

Fruit fly trouble generally begins as the weather warms in August, however Strathbogie Shire locals report winter fruits like manderins and oranges are now being affected too as our climate warms.

Flies lay their eggs under the skin of ripening fruit, maggots hatch and feed, spoiling the fruit, causing it to rot and drop.

Strathbogie Shire is assisting to implement the Goulburn Murray Region Fruit Fly Action Plan, which is aiming to achieve an Area of Low Pest Prevalence.

This will enable the right conditions for release of sterile male flies from the Sterile Insect Technology Program.


Taking action at home

Are you a home gardener?

Read our Home Growers Column

Everyone can play a role in protecting against the spread of the pest!

Read our Community Column


1. Determine if and/or when you have a fruit fly problem.

You can obtain pheromone based traps that contain female fruit fly odours, which attract males, and an insecticide that kills them.

These traps indicate if fruit flies are active in your area and when you need to act.

Lynfield traps baited with cuelure have been very successfully used in Australia for many years.

2. Collect fallen fruit immediately

The first and most important step when attempting to prevent fruit fly attack is good hygiene.

Mature maggots pupate in the soil to remerge as adult flies and collecting infested fruit breaks their lifecycle.

Pick up fallen fruit as soon as it drops before maggots have a chance to escape from the fruit and burrow into the ground to pupate.

3. Destroy eggs and pupae

To kill maggots, immerse infected fruit in a sealed bucket of water for 5-7 days or put them in a sealed plastic bag and put it in the sun for a similar length of time.

You can also put fruit in a plastic bag and microwave, or freeze them for two days.

If you have chooks, they will appreciate them after that!

4. Regularly inspect your fruit

Signs that eggs have been laid in fruit or veg are dimples or weeping clear sap on the fruit where the female fruit fly has pierced the skin to lay her eggs - called a sting.

Pick these fruit off as well as any damaged and rotting fruit.

5. DO NOT put untreated produce in your compost or worm farm as this will aid the Queensland Fruit Fly life cycle

Also, do not dispose untreated produce directly into your rubbish or green bin, as it may cause a new infestation in another area.

6. Make your own traps.

If you don't want to spend money on traps, you can make your own.

Start by making some holes half-way up a plastic drink bottle.

They should be about 10 mm wide and evenly spaced.

Fruit juide is best for the lure but add a pinch of sugar and a sprinkle of brewers' yeast to make fermenting sweet syrup that Fruit Flies just can't resist.

BE AWAREthat beneficial pollinating insects will also be attracted to homemade traps.

Hang 2-3 traps per tree and change the lure weekly when fruit flies are active.

7. Harvest produce early

If possible, harvest the produce early if it will continue to ripen after it is picked.

Harvesting prior to ripening removes fruit from trees before female Queensland Fruit Flies can lay their eggs.

Planting fruits that can be harvested in late Spring and early Summer also removes produce before Queensland Fruit Flies have had time to build up their populations to plague proportions.

8. Create barriers to produce

Cover fruit trees and garden areas with very fine UV stable mesh netting over a frame, using PVC tubes and stakes as a frame.

Alternatively, use an outdoor gazebo with zippers as it is easier to inspect trees and harvest fruit when it ripens.

Depending on the produce, you may need to install nets when fruit begins to develop so insects can pollinate flowers early in the season.

All nets should be secured around the trunk base or to the ground to protect your crop.

9. Use 'exclusion' bags and sleeves to keep fruit safe

When fruit begins to develop, place bags and sleeves over the fruit you wish to keep.

Remove any flowers or developing fruit from the plant that are not covered by the barrier.

Secure bags and sleeves to the plant with tie wire, clothes pegs or string.

The bags also keep birds out as well as protect the fruit from sunburn.

Nets, bags and sleeves can be purchased from nurseries and home garden retailers.

10. Create barriers to infested soil

If you have had a fruit fly infestation previously, fruit fly pupae may be in the ground under your fruit trees.

In this situation, secure the bottom of the net to the trunk base to stop any adult fruit flies emerging from the ground to inside the net.

If they are inside the net, Queensland Fruit Flies can infest your crop.

11. Baiting

Baits are an insecticide that is mixed with a Queensland Fruit Fly food attractant.

They are usually spot-sprayed onto the trunk and branches of host plants, which the pests feed on while they are in the tree canopy.

These treatments are often used to reduce Queensland Fruit Fly numbers in an area.

Baits can be purchased from nurseries and home garden retailers.

Commonly used fruit fly baits such as'DacGel' come in powder form which can be mixed with a common garden insecticide and sprayed from a spray bottle.

Inexpensive organic baits are now entering the market and include registered productswhich contain fruit fly attractant and spinosad - a natural insecticide.

Once a fruit fly lands, the insecticide will disrupt its nervous system, resulting in rapid fly death.

Most organic baits can be purchased at local Strathbogie Shire garden centres or online.

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