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Polyphagous Shot-Hole Borer

Learn about the PSHB and your role to help in the City of Kwinana. . Find out how to identify this invasive pest, its impact on trees, and the steps you can take to help prevent its spread.

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Polyphagous Shot-Hole Borer (PSHB)

What is PSHB?

The polyphagous shot-hole borer (PSHB) is a tiny beetle from Southeast Asia that can harm many types of trees and plants. It tunnels into tree trunks, stems, and branches, leaving behind small holes and creating spaces to lay its eggs. While boring, the beetle spreads a fungus that feeds its larvae. This fungus can damage the tree by blocking the flow of water and nutrients, which can lead to stress, dieback, or even the tree's death. PSHB is a serious problem because it attacks a wide variety of trees, including native and decorative species, threatening urban areas, farms, and natural ecosystems.

How does PSHB harm trees?

PSHB beetles have a relationship with a fungus called Fusarium. They grow this fungus inside the tree to feed themselves and their larvae. The fungus stops water and nutrients from moving within the tree, making the tree sick and eventually causing it to die. PSHB also weakens the tree by damaging its structure.

Current situation in Perth

The Department of Primary Industries and Regional Development (DPIRD) has found PSHB in the Perth area. Kwinana is now within Quarantine area B to prevent the spread of this beetle. This means wood and plant materials cannot be moved out of the area for further updates on this please visit the DPIRD website.

Why is this a problem for WA?

If PSHB spreads in Western Australia, it could seriously harm our city trees and may also impact agriculture. Since 2021, DPIRD has been running a national program to stop the spread of this beetle.

What You Need to Know

  1. Check Your Trees.
    If you see signs of this beetle on your trees (like small holes or sawdust), report it immediately. PSHB is very small, about the size of a sesame seed.
  2. Follow Quarantine Rules.
    If you live in a Quarantine Area, do not move untreated wood or large plant materials from your area without checking the rules
  3. Help Stop the Spread.
    Be careful when moving wood or plants and buy local firewood for camping. If you cut branches or plants, check for signs of PSHB.
  4. What Can You Do? 
    Use mulch from trusted sources, keep tools clean, and avoid moving green waste out of the Quarantine Area. Inspect, asses and be sure to purchase new plants from trusted sources.

What to Look Out For  

  • Beetle entry hole

    The entrance holes of PSHB are approximately the size of the tip of a ballpoint pen tip.

  • Discolouration or staining of wood

    The Fusarium fungus grown by the beetle can cause dark stains. These may appear in the tunnels they make and sometimes on the outside of the tree near the entry holes.

  • Gumming

    Gumming is a thick resin or sap that the tree produces when the beetle bores into it. Sometimes, this sap forces the beetle out of its tunnel.

  • Sugar volcano

    When the PSHB tunnels into a tree, the tree reacts by producing a thick, sugary sap or resin, which can sometimes look like a small, volcano-like eruption around the beetle's entry point. This "sugar volcano" is part of the tree's defence mechanism, trying to push the beetle out by oozing sap.

  • Frass

    Frass, which looks like sawdust, is created by the beetle as it tunnels. Seeing frass or "noodles" coming out of trees can be a sign of a severe infestation.

  • Dieback

    In vulnerable trees, the Fusarium fungus blocks the tree's vascular system, stopping the flow of water and nutrients. This leads to the branches dying off, causing the tree to lose its leaves and eventually die.

How to Report PSHB

If you think your tree might be infested, contact the Department of Primary Industries and Regional Development (DPIRD):

For more details, click below.

 DPIRD Website

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City of Kwinana kaditj kalyakoorl moondang-ak kaaradj midi boodjar-ak nyininy, yakka wer waabiny, Noongar moort. Ngala kaditj baalap kalyakoorl nidja boodjar wer kep kaaradjiny, baalap moorditj nidja yaakiny-ak wer moorditj moort wer kaditj Birdiya wer yeyi.

The City of Kwinana acknowledges the Traditional Custodians of the land on which we live, work and play, the Nyoongar people. We recognise their connection to the land and local waterways, their resilience and commitment to community and pay our respect to Elders past and present.

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