Queensland Fruit Fly

Qfly has a very short lifecycle (approx. 32 days) so there can be many generations in a season.

Due to its size and speed the Qfly is not that easy to identify and often the only time you will see one is in a monitoring trap. The Qfly larvae is even harder to identify, and the only definitive test is an expensive DNA test.

Here are some tell tail characteristics to keep an eye out for on an adult fly.

• Size – 6mm to 8mm
• Brown body colour
• Yellow GT stripes
• Yellow shoulder pads
• Yellow on thorax

Unfortunately, the Qfly is not very fussy. Any fruiting plant is a potential Qfly nursery. While they love the classic stone fruits and feijoas, all our fruiting trees are potential targets (apples, pears, citrus, olive, persimmons etc), fruiting vines (berries, grapes, passionfruit, melons etc) and even summer fruiting veggies (tomatoes, cucumbers, peppers).

While there are some fruits and fruiting vegetables that may be less attractive to Qfly this can depend on the local geography and climate, variety and availability of other hosts fruits.

For further information visit the Agriculture Victoria website. 

If you are starting a new garden or redeveloping or maintaining an existing one, doing some planning that incorporates the risk of Qfly is important.

Things to consider include:

• Having your own Qfly Action Plan which could include ongoing prevention strategies, garden maintenance and hygiene, and what to do if Qfly infests your fruits / vegetables
• Remove old fruit trees that you can no longer harvest / maintain / net 
• Hard prune fruit trees to get them back to a manageable (nettable) size 
• Plant fruit trees grafted onto dwarfing root stock or espalier trees to keep manageable
• Undertake summer / winter prunes for tree health and size management
• Thin out large crops as the fruit grows
• Don’t plant too many veggies (e.g. tomatos)

Qfly traps are used to alert you to having Qfly in your garden. While they can catch some Qfly, they will not catch all the Qfly around so are insufficient as a control on their own.

It is good to use the traps all year around so you will know if you have Qfly in your garden.

There are lots of trap products available, but they have similar features:

1. A lure to attract Qfly - There are two types of lures. Protein lures will attract both males and females. Pheromone lures will attract male Qfly. It is recommended that you use both in your garden
2.  Enclosed to keep Qfly in - Traps are usually yellow with a clear plastic cover to make inspection easy
3.  Something to kill Qfly – This can be an insecticide or a sticky insert

At Edendale we sell the BioTrap which can be used for both protein and pheromone lures and can use a sticky insert rather than a pesticide which is safer for you and the environment.

For the BioTrap, the pheromone (male) lures have a reach of approx. 400 meters and the protein lure about 15 m2. Other products / brands may have a different reach. In an average backyard garden one pheromone (male) and one or two proteins (female and male) should suffice.

You can also make your own protein trap with an old bottle - click here(PDF, 2MB)

The BioTrap lures should be refreshed approximately every 3 months, and the traps should be inspected regularly (e.g. weekly) to determine if Qfly is around.

Place the monitoring traps in a tree approx. 1.5 meters off the ground, facing the morning sun with some protection from hot afternoon sun as if they get too hot, the Qfly won’t enter.

In winter move the trap to a warm spot in the garden e.g. on an evergreen tree near a wall, as this is where the Qfly may overwinter.

Bating is an effective control in some environments, but it can be challenging in a suburban / urban context.

A bait is a mixture of protein and pesticide which is placed on a tree (branch, trunk, leave) e.g. as a spray on a weekly basis or after rain. As it is protein based it attracts both male and female Qfly, they will consume the protein and insecticide and die.

Baiting is not an effective control for a home gardener working alone and needs to be organised and coordinated through a neighbourhood, suburb or town wide program.

Having good garden hygiene practices is a very effective way of minimising the risk of Qfly infestation. Good garden hygiene practices included:

• Thinning / removing fruit from the tree early if you are not going to harvest it
• Regularly checking your fruit for sting marks as it grows and matures
• Pick fruit as it is ripening therefore preventing it from falling to the ground
• Invite friends / families in to harvest your (Qfly free) harvest, especially if you are on holidays
• Remove damaged fruit and process / destroy appropriately (see section 6)
• Don’t let fruit fall into the gathered netting around the trunk
• Pick up any fallen fruit
• Running poultry under fruit trees can be effective in managing fallen fruit and exposing and eating pupae in the soil, but is not fool proof
• Inspect any fruit / veggies from produce swaps for signs of Qfly BEFORE bringing it home
• Warning - Don’t put infected fruit in the compost (refer section 6 – disposal)

Exclusion through the use of netting is one of the most effective control strategies for the home gardener to reduce the risk of Qfly. There are options to net the whole tree, individual branches or just clusters of fruit.

To be effective the insect netting needs to have a very small aperture of either 2mm x 2mm or 1mm x 3mm. Anything larger and they can get through. You also need to make sure that the net doesn’t touch the fruit as the Qfly can still sting through the netting.

If you are netting the whole tree the options are

1. Drape the net over the tree, gather and tie it off around the trunk; or (Add image)
2. Place the net over a structure and secured the net to the ground with no gaps (add image) 

It is important that the netting has no holes to let the Qfly in so be careful when removing and storing the nets.

At Edendale we sell some netting options for the home gardener (add Link)

2mm x 2mm VegNet	Tree Netting	Branch Netting

If you do end up with Qfly damaged fruit it is very important you dispose of it correctly so as to break the life cycle.

The first rule is NEVER put Qfly damage / infected fruit directly into a compost bin, worm farm, landfill bin or green waste bin and do not bury it in the garden. In all these scenarios the Qfly will likely move to the pupae stage and the life cycle will continue.

You need to destroy the eggs and grubs before disposing of the fruit. Depending on the size of the crop the options include:

• Freezing the fruit till it is solid. This could be from 3 days to a week, depending on the freezer and the quantity of fruit
• Boil, bake or microwave
• You can also solarise the fruit in a black plastic bag but you have to make sure there is LOTS of hot sun for about a week and that the bags won’t attract dogs / foxes / possums etc that can rip the bags open to get to the fruit.

When convinced that all eggs and larvae are dead you can then

• Feed to the chooks
• Feed to the compost
• Add to the FOGO bin (if you have access to this system)

Another option is, after treating per above, to double bag the processed fruit and send it to landfill.

Qfly at its most active during the summer with an accelerating life cycle.  Adult flies are feeding, breeding, searching for suitable hosts, and laying eggs whilst also Resting in shady plants

Summer Actions

• Install and maintain monitoring traps
• Refresh lures and insecticides / stickies
• Thin crops to what you want to harvest
• Net crops after fruit / veggie set and thinning (before ripe)
• Harvest any damaged fruit
• Pick up any fallen fruit
• Dispose of affected fruit suitably
• Summer pruning (after harvest) to maintain tree size
• Get someone to harvest your fruit if you are on holiday
• Inspect any fruit / veggies obtained from produce swaps before you take it home

Qfly is still active in autumn (March to May). Its  Life cycle will be slowing down but late ripening fruits like citrus, apples and pears are still susceptible to attack

 Autumn Actions

• Continue with monitoring traps
• Refresh lures and insecticides / stickies
• Thin fruit load to what you will harvest
• Continue netting unharvested fruiting trees and vegetables
• Clean up fallen fruit
• Late summer pruning to reduce growth
• Inspect any fruit obtained from a food swap before taking home

Qfly is largely inactive during winter with adult flies with looking for a sheltered warm spots around the garden to spend the winter. Eggs / larvae in fallen fruit and pupae in the soil may survive over winter if the conditions are right.

Winter Actions

• Move monitoring traps into ever green trees in a warm spot (e.g. lemon tree)
• Refresh lures and insecticides / stickies
• Cleaning up any fallen fruit
• Winter pruning to manage size of trees
• Remove unwanted / unmanageable trees
• Plant trees on dwarf fruit stock
• Plan you spring program
• Get your netting repaired and ready

Overwintering Qfly start to become active when temperature increases to about 15-16 ℃ (Late Aug / Sep).  Female Qfly search for protein to fuel egg development. By late spring Qfly may have laid eggs in early ripening fruit so the cycle has begun and accelerates

Spring Actions 

• Install male (Pheromone) traps to try and disrupt the mating cycle
• Install protein traps to monitor and capture females and males
• Refresh lures and insecticides / stickies
• Starting to monitor too late could allow Qfly to build up rapidly undetected
• Ensure your nets are repaired and ready to go
• Inspect any fruit you get from a food swap before taking it home (e.g. Lemons)

 Webinar 1 - Qfly for the Home Gardener

 Presented September 2021 by Richard Rowe (Edendale Farm), Bronwyn Koll (QFF Regional Coordinator  Yarra Valley), Stephanie Orive (Land Management Officer Nillumbik)

Copy of Slides(PDF, 3MB)

Webinar 2 - Qfly for the Gardening Industry

Presented by Andrew Jessup - Horticultural Entomologist

• Nillumbik Website - Pest Animals - Queensland Fruit Fly

Videos on Qfly

• Fruit Fly Management for Vegetable Growers - Horticultural Innovation Australia
• Controlling Queensland fruit fly in home gardens – Agriculture Victoria
• Gardening Australia story at Edendale
• Meet Ernie the Fruit Fly
• Prevent Fruit Fly
• Make your own Qfly Trap(PDF, 2MB)