Polyphagous shot-hole borer
Polyphagous shot-hole borer is an invasive beetle species that infests a wide range of trees, causing damage by boring into the wood and spreading pathogenic fungi. A Quarantine Area divided into two zones is in place with rules applied to the movement of wood or plant materials.
About the Polyphagous shot-hole borer
Polyphagous shot-hole borer (PSHB, Euwallacea fornicatus) is a small beetle native to Southeast Asia that tunnels into the trunks, stems and branches of trees and plants. This beetle is highly invasive and attacks a wide range of plant species, with over 500 documented globally to have been affected.
The department is responding to a detection of this invasive pest in the Perth metropolitan area and has implemented a Quarantine Area (QA). This restriction aims to prevent the spread of the pest by limiting the movement of wood and plant materials.
PSHB was detected in WA in August 2021. Since then, the department 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.
Current situation
To date, PSHB has been contained to the Perth metropolitan area. Intensive surveillance and management activities are underway across the metropolitan area which include:
• Surveillance to determine the distribution of PSHB.
• Containment of the pest to prevent further spread to non-infested regions within Western Australia.
• Removal of infested plants to eradicate the beetle and save healthy, non-infested plants.
• Providing information and advice to the public, industry and other stakeholders.
• Ensuring all response activities are conducted safely, consistently and efficiently.
In addition to the Perth metropolitan based surveillance, the department has deployed PSHB surveillance traps in multiple regional areas including Harvey, Mt Barker, Manjimup and Bunbury. To date these traps have not returned any positive PSHB detections.
Suspect an infestation?
Report a suspected PSHB infestation by using the MyPestGuide® Reporter app.
Report via MyPestGuide
Quarantine Area
A Quarantine Area Notice restricting the movement of wood and plant material has been put in place to help stop the spread of PSHB. The quarantine area covers the entire Perth Metropolitan area, spanning 30 local government areas. The QA encompasses two zones:
- Zone A covers an area with high numbers of infested plants and has intensive control activities, such as plant removal, underway. This zone has more restrictions on the movement of high-risk materials.
- Zone B covers an area with fewer to no infested plants and has heightened surveillance underway to identify and control any new infestations discovered. This zone will help create a buffer between areas of high infestations and the rest of WA to further protect our flora.
Enter an address into the interactive map below to see if a property is in one of these zones.
What plants are affected?
PSHB causes serious damage to many types of trees and plants with a global host list covering over 500 species. When infested, a plant can show symptoms such as dieback, shotholes, galleries, frass and gumming.
Reproductive hosts are susceptible trees in which both the beetle and the fungus successfully establish and reproduce. The global host list is extensive with over 100 reproductive hosts.
View the list of affected plants and trees in Western AustraliaKeep an eye out
Detection of PSHB can be difficult as they are very small – roughly the size of a sesame seed. However, there are several symptoms that can indicate a plant may be infested.
Watch the animation below on YouTube to learn more and find out how to report PSHB sightings.
How does PSHB spread?
PSHB is a tree-boring beetle that has a symbiotic relationship with a Fusarium fungus. It cultivates this fungus inside of plants as a food source for themselves and their larvae. In susceptible species, the fungus kills the plant by restricting or preventing the movement of water and nutrients. This causes symptoms such as Fusarium dieback that eventually leads to plant death. The beetle also causes structural damage by creating tunnels, known as galleries, throughout the plant.
Native to Southeast Asia, PSHB has spread to countries including Israel, the USA South Africa and Argentina, and is now in WA. It is possible PSHB ‘hitchhiked’ its way to Australia on untreated wooden articles and packaging materials. Subsequent spread can be aided by the movement of infested wood (such as pruned trees, firewood) or wooden products such as furniture.
Actions to minimise the spread
- Monitor susceptible species including your local street and park trees for signs of PSHB damage and report any suspicious infestation signs to the department.
- Talk to your family, friends and neighbours to spread awareness to this invasive beetle
PSHB does not move far on its own but can travel long distances when people unknowingly intervene. Firewood can catalyse and provide a great mechanism for the distribution of PSHB without you knowing.
- Don't move firewood long distances including when you go camping - buy it where you burn it.
- Don't burn wood from host trees, especially if it looks like it has borer damage. PSHB beetles disperse when infested wood is burnt.
- Use grass clippings or compost as mulch as possible in your garden as wood chips from non-reputable places can spread PSHB
- While pruning or gardening check your plants and branches for sign of PSHB
- Disinfect pruning tools. Any tools (including chainsaws and woodchippers) that come into contact with infected wood should be sanitised before using on uninfected trees
- Avoid moving plants or wood products too far from your local area inside your QA zone.
- Don’t move plants, wood or green waste from a known PSHB infestation area
- Follow the current QA requirements
- Plant native species over exotic plants. See the recommended plant list here
- Don’t take it upon yourself to dispose of a possibly infested plant
- Contact the department regarding any questions or advice
Management of infested trees
PSHB can severely damage host plants by excavating tunnels in plants in which they cultivate the Fusarium fungus. This fungus occludes the vascular system of the host plant preventing the transport of water and nutrients. Consequently, some plants can die within a period of two years. Plants infested by PSHB can quickly become a public safety hazard and a breeding ground for the beetles to then disperse to neighbouring plants, causing spread.
Unfortunately, there are currently no effective chemical treatments for PSHB as the Fusarium fungus prevents systemic insecticides and fungicides from reaching the borers. Furthermore, surface application of chemicals is ineffective as PSHB spends most of their lives inside the host plant.
The department recognises the significant value of plants to individuals and the community. Treatment of infested trees, via pruning or removal, is determined by a number of factors including tree species, level of infestation, risk of further spread and risk to public safety. We are working closely with local councils, other government agencies and residents in the Perth metropolitan area to respond to detections of PSHB.
If you suspect PSHB activity in your plants, contact the department for advice and do not take it upon yourself to treat suspected symptoms. Incorrect treatments can cause further damage to the plant and can aid in the spread of PSHB. A direction to remove an infested tree will only come via the department following the issue of a Pest Control Notice (PCN).
Legal duty to report
Euwallacea fornicatus (Eichhoff, 1868) is a declared pest in WA. It is a prohibited organism under section 12 of the Biosecurity and Agriculture Management Act 2007.
This means that any person who finds or suspects the presence of polyphagous shot-hole borer must report it to the department.
More information
-
PSHB Alert factsheetpdf (537 KB)
-
PSHB Quarantine boundary mappdf (423 KB)
Polyphagous shot-hole borer Quarantine Area - September 2024
-
PSHB Quarantine Area Noticepdf (201 KB)
-
PSHB Affected plants list - WApdf (322 KB)
-
PSHB Affected plants list - Globalpdf (634 KB)
-
PSHB Approved green waste sitespdf (144 KB)
-
PSHB Frequently Asked Questionspdf (386 KB)