24-05-2025
Aussie council's innovative idea to combat invasive pest taking down city's trees
An Aussie council believes it has found a way to fight back against an invasive pest that is infecting and destroying trees across the city. In most cases, when the bug is found, there is nothing that can be done other than to chop off affected limbs or cut down the tree.
Native to Southeast Asia, the polyphagous shot-hole borer was first found in Fremantle, WA, in 2021 — confusing experts on how it got into the country and sparking fears the destructive beetles could wipe out forests and agricultural crops. The issue has since escalated rapidly, with entire sections of greater Perth put into quarantine in September last year as authorities scrambled to thwart the tiny critter.
In November, the City of Canning, which overseas the southeastern suburbs of the Western Australian capital city, urged residents to help in the fight by keeping an eye out for the pest, especially if they had a particular list of trees in their garden.
Earlier this year, the council began a state-first trial by pioneering a new technique to thwart the invasive pest. The council has been injecting infected trees with small pills filled with fungicide and insecticide in a bid to kill of the pest and restore tree health.
And the early data is very promising.
"The City is continuing its trial of chemical treatment of Polyphagous Shot Hole Borer (PSHB) at Bicentennial Adenia Reserve to gather further data supporting the current findings," the city's mayor Patrick Hall told Yahoo News on Friday.
"Following a recent inspection from Department of Primary Industries and Regional Development (DPIRD) representatives a reduction in the number of live beetles and active fungus in borer galleries has been confirmed."
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According to Hall, every local government in WA "is under threat" from the species. While the City of Canning is confident the early signs from the trial could put them on path to some sort of panacea, the results are still being reviewed by the council's academic partners "for validity".
"While not a complete solution to PSHB, this trial is part of the City of Canning's commitment to sustainable urban forest management and is a key step in an integrated pest management approach, combining tree health initiatives, pruning, and innovative control methods," Hall said in a statement to Yahoo.
The council will release further information as additional trial data is reviewed.
Speaking to Nine News Perth this month, John Szymanski from BioHerbicides Australia, which is helping carry out the field work in the trial, explained the simple idea.
"I thought hang on, it's an insect, it's a fungus, why can't we put an insecticide and a fungicide in the capsule, and put it in the tree?
"It's the difference between keeping a tree alive, and just removing it," he said.
The council wants state government endorsement and funding to conduct further trials and hopes the treatment ultimately means fewer trees will have to be cut down and the door opened to potential eradication. If so, it's a technique the council says could be used in other parts of Australia where the pest has caused trouble.
Meanwhile residents in WA are urged to keep doing their part and remain vigilant for the bugs.
If anyone discovers tiny holes the size of a ball point pen in clusters, they are urged to report the suspected infestation to DPIRD.
Affected trees can "quickly become public safety hazards and a constant source of beetles that can disperse to neighbouring trees, causing spread," the department's website says.
Originally from southeast Asia, the tiny creatures have now invaded several countries including the United States and Israel. One of the worst impacted countries is South Africa where it's estimated to have caused $28 billion in damage.
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