An increase in fire ant infestations along Queensland’s Logan River is raising concerns Australia’s worst invasive species could form floating rafts and spread downstream.
The Invasive Species Council advocacy manager, Reece Pianta, said governments should urgently ramp up eradication efforts along the Logan River, in south-east Queensland.
Pianta said the colonies posed a “very high risk” of further spread.
“These fire ants along the Logan river are growing in density and becoming a problem, because they can get into turf, soil and hay, and move to other areas,” he said.
“They can spread in flood events, to land on and reinfest properties where the fire ant colonies had previously been destroyed.”
The invasive insects can float on flood waters by forming large balls or floating rafts. The fire ants can lock their legs together and form air pockets to protect the queen and her eggs.
Once they arrived on dry land, they can reform their colonies in new locations, Pianta said.
“In Queensland, we’ve just come off a couple of weeks of fairly solid rain, and we’re starting to see our first evidence of fire ants rafting,” he said.
“Our concern is that suppression doesn’t seem to be working because the fire ant infestation numbers are growing in that zone,” Pianta said. “More resources are clearly needed, more community engagement and probably some federal government funding support.”
Fire ant incursions into New South Wales have occurred since late 2023. In November this year, the NSW government placed a temporary suspension on turf movements from heavily infested areas of south-east Queensland, after the pests were found in turf delivered to Clunes, near Byron Bay.
“Fire ants won’t march into NSW; they will either be carried with materials such as soil, mulch, hay and turf, or fly in by natural spread from Queensland. Which is why we’re ramping up surveillance in these high-risk areas,” the NSW agriculture minister, Tara Moriarty, said at the time.
First detected in Queensland in 2001, fire ants were considered one of the worst invasive species to reach Australia, according to the federal government. They damaged agriculture and wildlife, inflicted painful stings on people and animals, and restricted everyday outdoor activities like picnics and sporting events.
In previous years, the ants have used flooding in Queensland to spread into new areas, as rafts are deposited by rivers or flood waters.
