The Department of Primary Industries (PIRSA) expands its Sterile Insect Technique (SIT) program in the Riverland to combat outbreaks across 16 different areas.
The incident controller for Fruit Fly Emergency Response, Jason Size, said that the success of the SIT program relies on low wild fly population numbers.
Hence being used as a response tool after on-ground eradication activities have ceased.
“The increase in the number of locations where we are now releasing SIT flies reflects our eradication efforts,” said Size.
This program is an effective weapon against the fight against the fruit fly and is usually implemented following on-ground eradication activities including:
• baiting;
• ground treatments; and
• spraying.
These combined activities, along with efforts by local growers, and residents against the pest, are yielding promising results in the Riverland.
Over half of the Queensland fruit fly outbreak areas in the region have not recorded new fruit fly detections in the last three months.
PIRSA SIT’s rear out facility manager, John Trappel, explained the outnumbering of the wild fruit fly population during SIT releases to crowd control.
“It’s like going to a football game to meet a friend,” he said.
“If you’re there and no one else is around, you will more than likely find your friend – and in our instance another wild and fertile fly – easily.”
“But if you put millions of people in the same area at once – as we do with a SIT release – it’s very unlikely you’d be able to meet up. becomes unlikely that a fertile wild Q-fly can find a mate.”
The SIT program works by collecting pupae and irradicating them at PIRSA’s Port Augusta SIT Facility before being transported to the rear out facility in Barmera, where they are then reared to sterile flies before being released across the outbreak areas.
Once released from the plane, the sterile Q flies will then breed with any remaining wild fruit flies thereby disrupting the fruit-fly life cycle.
“You want the wild fly population to be at a certain level when SIT flies are released, they easily outnumber the wild fruit fly population, making it difficult for wild Q-flies to actively search out other flies to mate with, impacting the breeding cycle,” said Size.