How to: protect against fruit fly

Photo - Linda Ross

The most feared pest of the fruit and vegetable grower is the Queensland fruit fly (Bactrocera tryoni). 

Hard work turns to horror when fruit is full of fruit fly grubs. 

Follow these tips to ensure that cutting open your home-grown treasure is thrilling rather than chilling.

Set Eco-Naturlure Traps

Fruit fly are most active from October to April but also occur outside this period so traps are most effective when set in late winter or early spring. One or two traps will cover the average garden. Eco-Naturlure traps attract male fruit fly only so are not a complete solution.

Monitor traps

Check traps regularly (daily if possible) for fruit flies. Any fruit flies in the trap will be males, and that means it’s time to:

Target females

After hatching, the female fruit fly must feed on a protein source to become fertile. Eco-Naturlure and Yates Fruit Fly Control contain an appetising protein and a hidden surprise, ‘Spinosad’, which knocks them dead. The female fruit fly needs to eat the solution so a fine spray is ineffective as it’s likely to dry before the fruit fly can feed. We like to use half a paint roller, soaked in the solution, and then hung in a PET bottle with the bottom cut out. The females can drink directly from the roller. When it dries it needs to be soaked again. One half-roller will be enough unless you have quite a few fruit trees.

Clean up any affected fruit

This step breaks the fruit fly’s lifecycle. Once the fruit fly eggs hatch in affected fruit and the larvae have had their feed, they drop into the soil to pupate, emerging as full-grown adults. If larvae inside affected fruit reach maturity, your chances of controlling the population are reduced. Pick up any damaged or leftover fruit, tie it in a plastic bag and bin it.

Exclusion products

Exclusion bags are an alternative solution. These waxed paper or fabric, re-usable bags are placed over individual or bunches of fruit. The bag prevents fruit fly and other pests damaging the fruit. Exclusion bags are time-consuming but effective. For more go to www.greenharvest.com.au

Text: Jake Byrne