Queensland Fruit Fly Blog #6 – Essential Action Now

Now is the time to net your fruit trees and vegies as pollination has taken place. When netting trees, secure the bottom of the net to the tree trunk or ground and make sure there are no holes. When using net bags make sure the fruit is not against the mesh as it can be stung through it (insert a stick or wire to spread the bag open).

Protein baits for QFF must be placed in fruit trees now at the latest. Early positioning in August – September is ideal as once QFF is around it is too late but if you have not done that, do not delay. You may be in time for fruit that will be harvested in 6 weeks.

If spraying with kaolin clay, continue to monitor trees and reapply when it wears off.

The best protein baits are store bought such as Ceratrap and Biotrap. These will last the season if properly positioned. They should be placed high (at least 2m high in the canopy under the leaves on the north-east side). If they become full of insects, decant through a strainer lined with paper towel and reuse the liquid.

Home-made protein baits need to be replaced weekly. As they begin to rot they give off ammonia which attracts blowflies and some beneficial insects and this causes more deterioration as does catching large numbers of QFF. As the protein bait deteriorates it becomes ineffective.

Dispose of infected fruit immediately by solarising (7 days in double black plastic bags), freezing (24 hours or until the centre of the package is frozen solid), cooking: boiling (10 minutes), microwaving (3 – 10 minutes depending on quantity). Verify by cutting fruit open and checking that larvae are not moving.

Do not transport fruit or vegetables to areas that are free of fruit fly.

Do not bury or compost infected fruit as QFF pupate in the soil.

Finally, QFF females inject a bacterium into fruit and vegetables that make, even the unaffected parts, unsuitable for human consumption.

Read all our posts on Queensland Fruit Fly.

Written by Paul Gale-Baker