Managing the Q Fly Menace

The Queensland fruit fly is spreading south. It is the pest that makes me think twice before eating stone fruit because of the systemic sprays involved in the chemical control of this pest. However, there are other management options, including the following:

Control Strategies

The most widely employed strategy at this point is blanket spraying with dubious systemic insecticides, which have proven to be a danger to those applying the spray and those eating the treated fruit. I have identified some alternative options below:

1. A strategy called “splash baiting” involves a yeast attractant tied to an insecticide that is sprayed only on the lower leaves of the fruit trees. This has been shown to be up to 90% effective and it is vastly preferable to the systemics, in that the fruit is not directly sprayed.

2. Cloth and paper fruit bags can be tied around the fruit as soon as it has formed. The waxed paper bags can also help keep out codling moth, but the reusable cloth bags can also offer protection against fruit bats and possums. This is only applicable to home gardeners or high value fruit as it is often too labour-intensive for other commercial production.

3. Chooks are worth their weight in gold in an orchard and it is really time for more growers to realise their potential. A single chook (chicken to the Americans amongst you) can eat thousands of weed seeds in a day. Weed seeds can lay dormant in the soil for up to 70 years awaiting the right conditions to trigger their germination. The chooks deprive them of that choice and reduce your need for herbicides. More importantly, in relation to Queensland fruit fly, these eagle eyed rovers will effectively convert maggot-filled, fallen fruit into high quality eggs, with almost as much value as the lost fruit. When the adult fruit fly emerges from the pupae it is trapped on the ground for 24 hours after emergence while the wings harden. If you have chooks present at that time they will rapidly identify this vulnerability and will fight each other to reduce your fruit fly problem. They will even scratch out the pupae that have yet to hatch when they realise that this delectable snack may be present.

4. Insects love colour and their preference varies from species to species. Queensland fruit fly favour the colour blue and, if we are intent on working with nature rather than against her, we should be utilising this “understanding”. In this case, it is as simple as depositing blue painted styrofoam balls on the ground and in the trees. These balls should be covered in non-drying glue. They will need replacing from time to time because they will be so encrusted with both male and female Queensland fruit fly.

5. Pheromone traps are often used as a monitoring tool, where the number of insects trapped are used as an indicator of spray requirements. However, there is one trapping technology that has proven so effective that many growers now use it as a primary control strategy. I am referring to the NTS product, Fly Bye™.

Fly Bye™ Breaks Breeding Cycle

Fly Bye™ was developed by a researcher who spent many years experimenting with combinations of essential oils from native plants. He eventually developed a formula that is such a powerful attractant of the male fruit fly that the besotted insects simply cannot resist their lust-driven urges. Hopeful males have been seen to travel hundreds of metres to the baited traps. In fact, when we originally trialled this formula, we were trapping multiple males in the midst of an industrial estate.

This strategy simply involves pouring a little of the liquid formula into plastic hanging containers, which are hung in the fruit trees at a rate of 5 per hectare. The traps need to be emptied and recharged from time to time, but they have proven a remarkably effective tool to remove the male from the equation. Unfertilised eggs cannot hatch and the destructive maggots remain the dream of a disappointed female. We have had so much positive feedback about this technology. Here is part of an enthusiastic “thank you” letter from North Queensland chilli grower, Craig Zwetsloot:

“When we used Fly Bye™, I struggle to describe the relief we experienced. We have never lost a fruit since the traps have been in place. Do not buy anything else because you will be wasting your time! This stuff is incredibly effective! We only have two trap stations per acre and we now have zero incidence of Qld Fruit Fly damage.”

Craig is using Fly Bye™ as his primary control strategy. The best approach is to set the traps in late winter/early spring so that they will pull the males from the equation as soon as they become active. This is a proactive strategy and, as such, it is essential to get in before the problems begin. If you would like to order Fly Bye™, please contact NTS on +61 7 5472 9900 or sales@nutri-tech.com.au.

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