Across Australia, many people enjoy spending time in the garden and creating a beautiful and practical outdoor space. For many, much of that enjoyment includes the ability to harvest fresh seasonal produce, whether it is in a large suburban block or even just from a few plants on the balcony.
But fruit flies can wreak havoc in the garden, literally destroying the fruits of your labour. Working out the best way to deal with fruit flies can be difficult. And using ineffective strategies wastes your time, energy and money. This guide to fruit fly control will help you understand the behaviour of fruit flies and make informed decisions about controlling these pests in your home garden.
For residents in rural or peri-urban areas, the activities you undertake to help control fruit flies will also be important for horticultural producers in your region. As fruit flies can move between crops, a fruit fly problem in your back yard can quickly spread to adjacent properties and orchards.
NOTE: South Australia and Tasmania are free from all economic fruit flies and implementing control measures in your backyard is not necessary. If you suspect you have fruit flies or have observed maggots in fruit, whether locally grown or imported please contact state authorities (SA – Fruit Fly Hotline: 1300 666 010, Tasmania – Exotic Plant Pest Hotline: 1800 084 881)
The best approach for managing fruit flies will also include different management activities throughout the year and which target specific aspects of the fruit fly’s behaviour.
What fruit flies are doing each season
The best control measures for fruit flies change through the season and are responsive to their life cycle.The life cycle of a fruit fly
While fruit flies may be active all year round in tropical regions, during spring (September to November) populations either start to become active or increase in size. This coincides with increased temperatures and the availability of suitable hosts. In early spring, overwintering adult flies become active and female flies will be looking for a source or protein which is needed for their eggs to develop.
By late spring, fruit fly may have laid eggs in some early ripening fruit and from this point onwards the larvae will develop and the fruit fly population will start to increase.
The main measures to use in early spring are fruit fly monitoring traps to identify when adult flies are first active, as well as direct control measures such as protein bait sprays and traps. Starting these control actions too late will allow fruit fly populations to build up rapidly.
By summer (December to February) fruit flies are likley to be at their most active. In warmer regions they might have already completed a full life cycle or more, while in cooler areas they might only just be becoming active.
At this time of year adult flies are feeding, breeding, searching for suitable hosts, and laying eggs in suitable host crops. When flies are not doing these things, they are resting in shady plants. If unabated, eggs and larvae develop in fruit and vegetables. And larvae emerge from fallen fruit to pupate in ground (and will later emerge from the ground as adults).
Many of the same control measures as for late spring are appropriate, including bait sprays and traps, and reapplying or refreshing these control regularly and according to directions will help maximise control. Any fallen fruit should also be collected, placed in a plastic bag and left in the sun for 5-7 days. This will remove any possibility for fruit flies to breed in these fallen fruits.
If fruit fly pressures are high, this may also be the time to use measures such as mesh screens to protect your crop.
Fruit flies can still be active in autumn (March to May), particularly if there are available hosts around and the weather remains warm. While the development of fruit flies may be slowing down, late ripening fruits like citrus, apples and pears are still susceptible to attack.
While continuing with bait sprays and trapping is appropriate if you observe fruit fly activity, this is especially the time of year to clean up fallen or unharvested fruits and vegetables. Placing these into plastic bags and leaving them in the sun (solarising) for 5-7 days will effectively cook the fruit and kill any fruit fly larvae inside. Small quantities of fruit can also be microwaved. Fruit should not be placed directly in the compost as this will not kill fruit fly eggs or larvae.
While fruit fly are inactive in winter (June to August) across most of Australia, adult flies will overwinter in sheltered locations. Eggs and larvae in fallen fruit, as well as pupae in the soil may also survive to some extent.
Cleaning up fallen fruit as you have done in summer and autumn should still be undertaken. As some pruning of trees will also occur during winter, now is a good time to ensure your fruit trees are not too tall to harvest (fruit you cannot reach could be a home for fruit flies).
Queensland fruit fly in your garden
Agriculture Victoria developed the following video about about the life cycle of Queensland fruit fly, how it spreads, and how to monitor fruit and vegetables for signs of infestation and control numbers in your garden.
Topics in this section
Developing a control strategyChoosing a control strategy
Understanding the tools to control fruit fliesFruit fly control tools
Advice for less able gardenersAdvice for less able gardeners
More information on the pest speciesMore on the pest species
NOTE: South Australia and Tasmania are free from all economic fruit flies and implementing control measures in your backyard is not necessary. If you suspect you have fruit flies or have observed maggots in fruit, whether locally grown or imported please contact state authorities:
SA – Fruit Fly Hotline: 1300 666 010
Tasmania – Exotic Plant Pest Hotline: 1800 084 881