Published on Monday, 30 June 2025 at 3:48:53 PM
PSHB was detected in WA in August 2021. Since then, the Department of Primary Industries and Regional Development (DPIRD) has been leading a nationally funded and coordinated biosecurity response. Allowing this pest to spread in WA could have a significant impact on our urban canopy and may pose a threat to our valuable agricultural industry.
PSHB is a serious pest threatening trees, agriculture, and bushland. This small beetle bores into trees and spreads a damaging fungus, affecting over 100 tree species. The fungus spreads inside the galleries and disrupts the plant vascular system and the flow of water and nutrients. The galleries reduce the structural integrity of branches which will lead to branch failure and even tree death. This disruption also makes systemic insecticides and fungicides ineffective in treating PSHB.
PSHB is NOT currently in the Shire of York — let’s keep it that way.
Help Prevent the Spread:
- Do NOT bring firewood, tree pruning’s, green waste, or potted plants into the Shire.
- Avoid moving wood or plant material without proper treatment (grass clippings are exempt).
What do PSHB look like?
- Female PSHB: 2 mm in length, brown to black, the only gender capable of flight.
- Male PSHB: 1.6 mm, wingless.
- Larvae: White, C-shaped, 3.5 mm long, with reddish heads.
Signs of Infestation:
- Small entry holes (like a sesame seed).
- Sawdust-like material around the base of the tree.
- Tree dieback or wilting.
Look for this Pest:
Beetle entry holes
The entrance holes are approximately the size of a ballpoint pen tip.
Discolouration or staining of wood
The fungus cultivated by the beetle can cause dark discolouration
"Galleries"
Tunnels excavated by the beetles where they cultivate a fungus.
Gumming
Thick resin or sap sometimes pushes the beetle out of the gallery.
Frass
Produced by the beetle’s tunnelling, frass or ‘noodles’ may be present extruding from trees. This can indicate the infestation level is high.
Dieback
In susceptible trees the Fusarium fungus kills tree vascular tissue causing branch dieback and tree death.
If you spot any signs of PSHB, report them immediately using the MyPestGuide app, or contact DPIRD’s Pest and Disease Information Service at:
Phone: +61 (0)8 9368 3080
Email: padis@dpird.wa.gov.au
Further information including an interactive map showing the zones and requirements can be found at below resources.
https://www.agric.wa.gov.au/borer
Polyphagous shot-hole borer | Department of Primary Industries and Regional Development
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