Pesticide free fruit fly control – is it possible?

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I was very interested at the last field trip to hear of Bruce’s success with fruit fly control. It set my mind wondering how a pesticide free trap might compare. As I am a Certified Organic grower I am unable (and unwilling) to use chemical pest controls. I have spent some time in the past trapping fruit fly but have never kept any records – there is plenty of anecdotal advice around on non-toxic options but no one seems to have documented any. As well as being interesting for my own use, I thought it might interest other members and inspire them to conduct their own research and report back, especially anyone able to compare chemical and non-chemical traps (which I am unable to do).

My traps consisted of two commercially available ‘baits’ and two home made ‘baits. Information given with the commercial baits is as follows –

Fruit fly lure – Yeast Autolysate. Used as an attractant with a compatible insecticide for the control of a range of fruit fly including Qld fruit fly and Mediterranean fruit fly. The attractant is mixed with an insecticide (chlorpyrifos, trichlorfon or maldison and applied as a coarse spray to the foliage of the trees. Highly attractive to female fruit flies. Suggested application – 20 ml in one litre of water, 50 ml per tree or 15 litres per hectare apply at 5-7 day intervals. Cost – about $12 per 250 ml. Supplier- Bugs for Bugs (07) 4165 4663 or your local produce store.

Wild May Fruit Fly Control System. Two products – Blue label eliminates the group of male fruit flies which include the Qld fruit fly and a number of species that attack stone and citrus fruits and a number of vegetable crops.  Red label for the control of Papayan fruit fly and a number of species that attack fruit and vegetable.  Suggested application 300ml per trap, two traps of appropriate attractant per acre.  Cost – about $7.50 per litre. Supplier – Wild May Essential Oils Mt Gravatt (07) 3349 5283

My trapping experiment

Use a small (300 or 500 ml) soft drink container and drill (about 6 mm), cut or burn (with hot skewer) three holes about a quarter of the way down the bottle. Place approximately 50 ml of selected attractant in the container replace lid and hang in tree (mine were as shady as possible). The bottles used were clear except for one which was blue, this was included because Bruce reported Dr Dick Drew as saying the female fruit fly was attracted to blue – if this was so the blue bottles should contain more dead flies! These traps work by attracting the flies into the small holes. They cannot find their way back out again and therefore perish.

Yeast autolysate – about 5ml dissolved in water to make about 50 ml (about 50 traps for $12).

Wild May – about 50 ml of each of the attractants in separate bottle (about 20 traps for $7.50).

Urine – about 50 ml in bottle (very economical !).

Sugar, flour, banana skin – about one tsp sugar, one tsp flour, water to make a thin paste and about a quarter of a very ripe banana skin cut into centimetre squares (to get it into the bottle (also very cheap).

The number of flies in each trap were counted and results recorded as follows:

The results show that fruit fly trapping without poison is possible. My trials will continue and I encourage other people to undertake research and report back.