An emergency biosecurity response to a fire ant outbreak in northern New South Wales appears to have contained the extremely invasive species.
In November, three red imported fire ant (Rifa) nests were found in Murwillumbah, 13km south of the Queensland border. The pests were detected by a member of the public and were suspected to have been transported from south-east Queensland, where there is a widespread infestation.
The invasive species can kill people and livestock as well as damage infrastructure and ecosystems. The National Fire Ant Eradication Program response to the detection included chemically eradicating the nests, baiting the surrounding area, using sniffer dogs to search for further nests and imposing strict limits on movement of farming materials within 5km of the site.
At the time, the NSW minister for agriculture, Tara Moriarty, urged vigilance, encouraging the public to be part of surveillance efforts.
New figures from the state government show the community has made 512 calls to the NSW biosecurity hotline, with all reports of suspected fire ants deemed negative.
There have been 283 inspections by staff and detector dog teams since the detection and more than 1,200 drop-ins to the NSW government’s fire ant information bus.
A further part of the response was to genetically test the ants to determine whether they were linked to the existing infested area in south-east Queensland.
Moriarty confirmed the results showed the ants were connected to the known outbreak, suggesting they had been transplanted to the site, possibly in a delivery of turf.
“At the time of detection, all fire ant nests were destroyed by direct nest injection and surveillance activity focused on the immediate area to check for additional nests – none were detected,” she said in a statement.
“The NSW government is not resting after eradicating the fire ant nests found in South Murwillumbah in late November last year.”
Reece Pianta of the Invasive Species Council cautioned the community had a way to go, with an outbreak only truly deemed eradicated when 24 months passed without further detections of Rifa.
While the spread beyond containment lines in Queensland was “not great”, it was being addressed effectively, he said.
In December, he visited the site with Craig Huf, chair of the Far North Coast branch of the NSW Farmers Association.
In addition to the positive genetic link to Queensland and a quick response by authorities and the community, Pianta said the terrain of the site was “in our favour”.
“The nearby terrain is open and suitable for efficient helicopter fire ant prevention treatments,” he said.
Helicopters are expected to bait the area with an insect growth regulator targeted at fire ants. Any worker ants remaining would take the bait to the nest and feed it to the queen. The bait turns off fire ant foraging instincts – preventing new colonies from forming.
“After decades of under-resourcing, increased fire ant funding is having a positive impact on fire ant responses,” he said.
State and federal governments have committed $593m to the eradication of Rifa between 2023 and 2027.
“Funding levels should be constantly reviewed to match resource needs on the ground. Eradication is a long complicated process but only eradication can prevent fire ants from spreading into NSW again.”
Huf said he welcomed the response so far but the infested area in south-east Queensland was “supposed to be contracting not expanding”.
He encouraged more random compliance checks on vehicles travelling from the infested area.
Vehicle checks as part of the November operation resulted in 75 heavy vehicle inspections. None were turned around, with the majority showing compliance.
Two checkpoints overseen by the NSW Department of Primary Industries and NSW police in September stopped 99 vehicles moving fire ant carrier materials, seven of which were non-compliant and returned to Queensland. Two penalty notices were issued.
