World:Queensland fruit fly aerial attack targets fruit-growing areas of Cobram and Hillston

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Millions of sterile Queensland fruit flies are being released from aircraft over two fruit fly-populated areas of New South Wales and Victoria during the spring and summer period.

Key points:

  • Two new areas have been chosen because the Queensland fruit fly is not native there
  • The reproduction of the fruit fly is reduced because female mates with the sterile fly
  • The dropped-in flies have a dye on them to easily identify the sterile flies

Sterile fruit flies have so far been only released from an aircraft in an emergency when fruit flies were found in a suburb of Adelaide which is a fruit fly-free area.

Examining a sterile fruit fly in the laboratory
Looking at a sterile fruit fly in the laboratory. (Supplied: PIRSA)

The inaugural experiment with the sterile fruit fly involves a number of states including South Australia where the flies are bred and Tasmania which is helping to fund the trial.

Professor Phil Taylor, a Director of the ARC Centre for Fruit Fly Biosecurity, said two fruit-growing areas of Cobram in Victoria and Hillston in NSW had been chosen.

“From now until April next year around 2 million sterile fruit flies will be released each week from a plane flying over farmland and the town areas of those two places.”

He said Hort Innovation was funding this unique trial where it would have scientists on the ground monitoring the effect the sterile fly would have on the normal fruit fly population.

“The two areas were chosen because the Queensland fruit fly is not native to the towns and the fruit fly population is not huge,” Professor Taylor said.

The sterile fruit flies are bred at the special breeding facility in Port Augusta in South Australia where production can rise to tens of millions of flies a week.

The sterile flies are then shipped out to holding centre in Tatura in Victoria and Yanco in New South Wales waiting for dispatch to the target areas.

A sterile fruit fly on citrus
A sterile fruit fly on citrus. (Supplied:PIRSA)

“Female fruit fly which mate with the sterile fly will fail to reproduce and this means a reduction in the wild population without the use of chemicals.”

“It’s something that’s safe to use in production areas and safe in townships and is a sustainable means of controlling this terrible pest,” Professor Taylor said.

“Basically we have an aircraft with a chilled device in it containing the flies and an augur is used from the plane to drip the sterile flies out of the back as it covers the test areas.”

“The flies have a dye on them and so we can easily identify the sterile flies, and each week we change the dye colour to see how long they survive in the wild.”

“Over the next few months we should see a decline in the numbers of wild flies but the program will take time to have a big effect,” Professor Taylor said.

A close up of a hand holding a container of pink dye for marking the flies.
Flies are marked with a bright pink dye so they can be identified in the wild. 

The sterile insect program does not kill the wild fly population but it’s a form of birth control that will affect numbers of the next generation.

Professor Taylor said he expected a carryover effect late in the summer next year and predicted low numbers of wild fruit fly at the start of next spring in the two areas.

“We can’t eliminate Queensland fruit fly across Australia as it is a native species but we can make areas like Cobram and Hillston fruit fly free zones.”

“In West Australia we can have programs to eliminate the Mediterranean fruit fly, as that is not a native to the west,” Professor Taylor said.

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