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In 2021, the polyphagous shot-hole borer (PSHB) was found in Fremantle.
Since then, it has wreaked havoc on hundreds of tree species.
So far, the efforts to eradicate this tiny pest have been unsuccessful. But new research might finally give scientists the upper hand.
SMALL BUT MIGHTY
PSHB (Euwallacea fornicatus) is a beetle native to Southeast Asia. It is roughly the size of a sesame seed, yet capable of damaging thousands of trees. This is thanks to its symbiotic relationship with a fungus (Fusarium euwallacea).
Credit: Ken Walker/Wikimedia Commons (CC BY 3.0)
As the borer tunnels into trees, it harvests the fungus as food for itself and its larvae. The fungus keeps water and nutrients from flowing within the tree, leading to severe damage and even death.
When first detected, the WA Government launched a multi-million dollar biosecurity response. Quarantine areas were established and thousands of trees were removed from parks, streets and homes.
However, in 2025, the WA Government declared that eradication would no longer be feasible. The beetles are hard to detect, they reproduce too fast and there are no effective pesticides against them yet.
Instead, the focus will be on the long-term management of the pest.
A NEW HOPE FOR WA’S TREES
In January 2026, PhD student Md Shahidul Islam Khan and Associate Professors Wei Xu and Rob Emery from Murdoch University announced that they had grown the first successful PSHB lab colony.
Credit: © Ezra Kaye/Murdoch University
The team obtained beetles from infested sites and replicated their natural conditions in the lab. The beetles displayed their typical behaviours, including the creation of tunnels and subsequent growth of the Fusarium fungus.
This means scientists can now observe the borer’s life cycle under controlled conditions to understand how it behaves and how it responds to chemical cues.
“With a stable colony, scientists can now rapidly and safely screen potential attractants, repellents and environmentally friendly control tools that are essential for early detection,” says Mr Kahn.
The development of PSHB lab colonies could also contribute to the management of this pest.
”This project represents an important step forward in protecting WA … from the ongoing damage caused by [PSHB],” says Dr Xu.
”By understanding this pest more deeply, we can develop targeted tools that safeguard the health and resilience of our landscapes for the long term.”
