The polyphagous shot-hole borer has proven too tough to handle as the Western Australian government announces it will transition to managing the pest rather than eradication strategies.
"The chief plant biosecurity officers from around Australia (initially) determined that eradication was possible," WA Agriculture Minister Jackie Jarvis said on Thursday.
The southeast Asian native pest was first identified in Perth in 2021 and tunnels into the trunks and branches of a wide range of species, including Australian native paperbarks and eucalypts.
The only effective treatment for affected trees is removal with thousands of trees having suffered the fate in Perth parks, including Kings Park and Hyde Park, and many more likely to follow.
"Protecting Perth's tree canopy and our valuable horticulture sector from shot-hole borer remains front and centre for WA," Ms Jarvis said.
While the insect is confined to the Perth metropolitan area, the news it can no longer be wiped out has horticulture experts concerned about a national spread.
"This is tragic news not just for Western Australia, but potentially for native trees, towns and cities, and the horticultural industry across the entire country," Invasive Species Council policy director Carol Booth said.
"Hundreds of native species across the country could be at risk if the borer spreads.
"The regular arrival of harmful new invaders shows our prevention systems are not strong enough."
Dr Booth expressed concern about the impact of the borer on the urban tree canopy, saying risks to habitats and human health were "immense" if the spread was not contained.
Thursday's state budget allocated $26.5 million to the amended borer management plan.
But the shift in strategy hasn't gone down well on the other side of the political aisle, with the WA opposition saying the minister must go.
"Minister Jarvis has admitted she failed to keep Western Australia protected," shadow agriculture minister Lachlan Hunter said.
"That is an extraordinary admission of failure, and she should resign."
Opposition Leader Basil Zempilas called on Premier Roger Cook to step in should Ms Jarvis refuse to step down.
"The premier should stand up, accept responsibility on behalf of the government and sack Minister Jarvis," Mr Zempilas said.
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