What is PSHB?

Polyphagous shot-hole borer or PSHB (Euwallacea fornicatus) is a beetle native to Southeast Asia. About the size of a sesame seed, PSHB excavates tunnels in trees where they cultivate fungus as a food source.

This fungus spreads in the tunnels of trees disrupting the flow of water and nutrients.

Trees damaged by PSHB can become a constant source of beetles that can disperse and impact neighbouring trees.

Check out the explainer video below:

How is it being managed?

The City of Vincent is following the lead of DPIRD as part of a nationally funded and coordinated emergency response to eradicate the borer from Western Australia.

DPIRD's response activities include:

• Conducting surveillance to determine the distribution of PSHB.
• Containing the pest to prevent further spread to non-infested regions within Western Australia.
• Providing advice and information to residents, industry and other stakeholders.
• Ensuring that all response activities are conducted safely, consistently and efficiently.
• Removing infested trees to save healthy trees.

Quarantine area

Vincent is included in DPIRD’s Quarantine Area.

It is important that people living or working within the Quarantine Area are aware of the restrictions on the movement of wood and plant material from their properties as they could act as hosts and potentially spread the borer.

PSHB does not affect grass so lawn clippings can be disposed of as normal.

Vincent is working with DPIRD to stop the spread of PSHB.

Quarantine area sheet

What happens to trees after they are removed?

DPIRD have a Tree Management Plan in place to guide the removal of trees and tree limbs in a way that will ensure the beetle is destroyed. Under this plan, all material from infested trees is chipped on site to a size less than 2.5cm. At this size, PSHB is not able to survive in the wood. The woodchips are then securely transported to a facility in Jandakot. 

What are the signs a tree is infested?

The top hosts of PSHB include Maple (Acer), Plane (Platanus), Robinia (Robinia), Poplars (Populus), Oak (Quercus), Avocado (Persea), Fig (Ficus) and Coral Tree (Erythrina).

Symptoms of infestation vary from species to species. The main things to look for include:

• Beetle entry/exit holes - approximately the size of a ballpoint pen tip.
• Galleries - when pruning branches or inspecting fallen branches, check for evidence of galleries caused by the tunnelling action of PSHB beetles.
• Discoloration/staining - this is caused by the Fusarium fungus.
• Gumming - thick resin or sap.
• Frass - produced by the beetles tunnelling, frass or 'noodles' may be seen on the tree exterior. This can indicate a high level of infestation.
• Sugar volcanoes - a common sign of infestation on Avocado trees, crystalline foam is exuded from entry/exit holes.
• Dieback and tree death - the fungus disrupts the tree vascular symptom causing dieback and death.

The female beetles are approximately 2mm in length, range from brown to black in colour and can fly to other close by trees.

The male beetles are smaller, at around 1.6mm in length, they don’t have wings and prefer to stay inside the tree.

Symptoms are not always obvious, if a tree is looking generally unwell, or there are early signs of dieback, inspect the tree closely for evidence of small bore holes.

If you see one, you are likely to see more, as they are often clustered in a shotgun pattern.

Removal of trees from the lakes at Hyde Park

DPIRD has confirmed that trees will need to be removed from the two islands in the middle of the lakes at Hyde Park. As part of this work, approvals and controls will be in place to protect wildlife. The City already has plans to revegetate the islands and restore habitat as quickly as possible after DPRID's works.