The national fire ant eradication program has extended its biosecurity zones around south-east Queensland, adding nearly 60 new suburbs across Brisbane, Moreton Bay, and the Scenic Rim.
The move comes as efforts return to cutting down fire ant numbers in Brisbane, Ipswich and Logan, while still working to contain the invasive pest's spread west through the Lockyer Valley.
Under the 10-year, $411 million program, two biosecurity zones were established to control the movement of soil, hay, and other ant-carrying materials, after incursions from the Port of Brisbane a decade ago.
But fire ants have proved challenging to stamp out, with the program last year announcing it needed more money to meet its 2027 eradication deadline.
Without eradication, the devastating agricultural pest is predicted to cost Australia an estimated $1.65 billion annually.
Controlling movement
Program manager Graeme Dudgeon said adding more suburbs to the zones meant controls would now govern how businesses and residents could move materials such as soil, hay, and plants.
"This particular update, while it sounds like a lot of suburbs … it's not a great increase in the area of the zones," he said.
"They're on the edge, so you would expect that to happen — there's been a little bit of spread on the edge, or we're worried about spread on the edge."
The western zone, covering much of the Scenic Rim and Lockyer Valley, has been the main focus of surveillance and treatment efforts to date.
The eastern zone covers Brisbane's southside, Ipswich, Beaudesert, Logan and the northern Gold Coast, and has had no treatment – although residents are encouraged to report or treat fire ant nests in their own back yards.
Mr Dudgeon said while focus had initially been on surveying and killing ants on the western boundary in the Lockyer Valley, the east now needed attention.
"In the area we're not eradicating, that eastern area, it was thought initially that responding to public reports of fire ants and immediately killing the fire ants when found and reported would be enough to keep those fire ants down to a reasonable level," he said.
"We found that's not the case, because there are more fire ant nests that you can't see than you can."
Thousands of fire ant reports have been made across Ipswich and Logan over the past 12 months, with new housing developments a popular home for the pest.
In comparison, the western zone — where treatment has been under way for several years – has had fewer than 200 fire ant reports in the past year.
Mr Dudgeon said said another $37 million had been put into the program over the next five years, prioritising the eastern zone.
North and south
Moreton Bay suburbs including Murrumba Downs and Griffin were on Thursday added to the eastern zone for the first time, along with a host of northside Brisbane suburbs such as Fortitude Valley and Northgate.
"In the [Moreton Bay] area, there's quite a few suburbs added there — there has been on-and-off fire ant activity there for a number of years," Mr Dudgeon said.
"It's not a lot of activity, but there's enough now for us to be concerned and we've added those suburbs in."
To the south-west, the western zone now the foothills of Main Range near Aratula, where fire ants have moved deeper into the Scenic Rim.
"That's an area where fire ants have been pushing quite hard," Mr Dudgeon said.
"We're not sure why there rather than somewhere else, but it seems the conditions for this breed there are quite favourable and that's where they seem to be moving."
Murray Darling fears
Fire ants in the Scenic Rim are edging closer to the Murray Darling Basin, a concern that has long been held by agricultural groups and the federal government.
But the Great Dividing Range still blocks their path.
"They could get there by human-assisted movement if someone takes infested hay across the range, for instance," Mr Dudgeon said.
"So it's really, really important we make sure that doesn't happen.
"If they get into the headwaters of the Murray Darling Basin, then there will be a problem."
Australia's agriculture ministers will meet later this year to review the program.
