Queensland fruit fly

Queensland fruit fly is the main fruit fly pest species that damages intact fruit on the tree. It can devastate commercial and backyard crops. Council has worked with the Harcourt Valley Fruit Fly Action Group, local Landcare organisations and Agriculture Victoria (the lead authority on fruit fly) to keep fruit fly out of our shire.

Harcourt Fruit Fly Action Group has developed an emergency plan to manage an outbreak of Queensland Fruit Fly (QFF) specifically for residential backyard growers, schools and small horticultural producers.

The group worked with Mount Alexander Shire Council to develop the plan supported by a grant from Agriculture Victoria. Read the plan on our fruit fly outbreak page.

The group also created the Harcourt Valley Fruit Fly Action Plan 2018-2019 which aims to prevent Queensland Fruit Fly from establishing in the Harcourt Valley. A key component of this to build awareness and education.

You can do many things to prevent Queensland fruit fly from becoming established in our shire. These include:

• Avoid bringing in fruit from other areas, particularly those known to have fruit fly.
• Set traps to monitor and reduce fruit fly numbers (watch the videos to see how you can make your own or talk to your local garden supplier about the different types)
• Dispose of infected fruit properly including fallen fruit on the ground.
• Remove unwanted fruit from trees.
• Keep fruit trees well pruned.
• Place fruit fly nets over your fruit trees and vegetables.

The fly: Is about 5-8mm long with reddish eyes. The fly is brown with yellow ‘shoulder pads’ and other markings including a yellow triangle at the base of the mid-section.

Images: Adult Female Queensland Fruit Fly (Image Agriculture Victoria); Adult Queensland Fruit Fly (Image James Niland).

The larvae: Are white or cream and 2-9 mm long. They are wedge shaped and plumper at the tail end. A black feeding hook is visible in mature larvae. You can find between 2 and 20 larvae in the fruit.

The pupae: Are like a large grain of brown rice and vary in colour from cream to brown.

The fruit: Infected fruit becomes soft and spongy and may start to rot. You may see sting marks on light coloured fruit. The flies may eat all the fruit and leave the skin.

Images: Fruit fly larvae in stone fruit (image: Applied Horticultural Research); fruit fly larvae (image: Agriculture Victoria); fruit fly pupae (image: Applied Horticultural Research).

Winter
- Males become active in late winter and early spring when they begin to mate. This is the time to monitor with fruit fly traps.
- Prune trees to a manageable height for ease of fruit picking and netting
- Replace unwanted fruit fly host trees with non-host plans
- Pick up fallen fruit
Remember: In the winter the risk of fruit fly is lower but winter fruits can provide a food source for overwintering fruit flies. These include apples, pears, quinces and pomegranates left hanging on trees and ripe winter citrus such as oranges, mandarins and grapefruit. Fruit fly may hibernate in citrus trees throughout winter.

Spring
- Remove fruit fly host plants if you are not going to control fruit fly in your garden
- Design your vegetable garden layout and cropping cycles so that fruit fly populations don’t build up
- Set up traps to monitor for fruit fly and check traps weekly
- Pick and dispose of any excess ripe citrus especially grapefruit and late season oranges
- Pick up and dispose of any fallen loquats
- Spray high risk fruit if appropriate and always follow label instructions.
Remember: In spring high risk fruits are late season citrus such as grapefruit and early ripening hosts such as loquats.

Summer
- Net your vegetable garden or bag individual fruit.
- Pick up fallen fruit everyday
- Check tomatoes and fruit for sting marks
- Heat treat fallen and infested fruit and vegetables to kill Queensland fruit fly maggots.
- Continue to trap and monitor fruit fly population levels weekly
- Spray high risk fruit if appropriate and always follow label instructions.
Remember: In summer high risk fruits are stone fruit such as cherries, apricots, peaches, nectarines and plums. High risk vegetables are tomatoes, capsicums and chillies.

Autumn
- Pick up any fallen fruit to break the fruit fly lifecycle
- Heat treat fallen and infested fruit to fill the fruit fly maggots
- Continue to monitor for fruit fly and check traps weekly
- Continue to spray high risk fruit if appropriate and always follow label instructions.
Remember: In autumn high risk fruits are pome fruits such as apples, pears and quinces, early citrus such as mandarins. Other fruit includes pomegranates and ornamental fruiting plants such as fejoa.

This information was sourced from the Season calendar of backyard jobs by the Goulburn Murray Valley Regional Fruit Fly Group.

To increase community awareness of Queensland fruit fly and explain what we can all do to prevent further spread, Council created a series of educational videos in partnership with City of Greater Bendigo. Thanks to Agriculture Victoria for their grant to support this work.

Check out our YouTube channel to see all five videos.

Video one: Pruning for success

Video two: Traps

Video three: Garden hygiene

Video four: Exclusion is key

Video five: Best practice

Harcourt Fruit Fly Action Group has developed an emergency plan to manage an outbreak of Queensland Fruit Fly specifically for residential backyard growers, schools and small horticultural producers.

The group worked with Mount Alexander Shire Council to develop the plan supported by a grant from Agriculture Victoria.
Read the plan on our fruit fly outbreak page.

The group also created the Harcourt Valley Fruit Fly Action Plan 2018-2019 which aims to prevent Queensland Fruit Fly from establishing in the Harcourt Valley. A key component of this to build awareness and education. See the plan below.

• Council's Queensland fruit fly outbreak page
• Agriculture Victoria - Queensland Fruit Fly
• Prevent Fruit Fly website
• Goulburn Murray Valley Regional Fruit Fly Group
• Harcourt Valley Fruit Fly Action Plan 2018-2019
• Latest Central Vic Queensland Fruit Fly Brochure
• Fruit fly management for vegetable growers - (PDF, 2.67MB) an excellent resource from Horticulture Innovation Australia.