Polyphagous shot-hole borer (Euwallacea fornicatus)

Euwallacea fornicatus (polyphagous shot-hole borer - PSHB) is a tiny beetle. It bores into tree trunks, stems, and branches and can lead to tree death. The beetle is an agricultural and environmental pest. It attacks amenity, native and horticulture production trees.

Detection in Australia

PSHB was detected in East Fremantle, Western Australia (WA) in August 2021. It’s unknown how and when the pest entered Australia.

There have been no detections of PSHB outside the Perth metropolitan area.

Response program

On 18 June 2025 the National Management Group (NMG), on advice from the Consultative Committee for Emergency Plant Pests (CCEPP), agreed that PSHB was no longer technically feasible to eradicate.

Reasons for this include the difficulty of detecting and controlling new infestations at early stages, and that there are no known effective chemical treatments available.

The response will now move to the initial phase of an 18-month transition to management program. Activities will focus on continuing to slow the spread of PSHB, and minimising the risk of spread beyond the Perth metropolitan region.

Over the next 18 months, the WA Government will work with industry, community and local government partners as part of the transition to build capacity to manage the pest.

The WA Government is also investing an additional $2.17 million through WA Agricultural Research Collaboration (WAARC) towards new research which aims to improve detection, surveillance and control methods for PSHB.

Movement restrictions remain in place and are critical to minimising the risk of human-assisted movement of PSHB out of the Perth metropolitan area.

WA government’s response activities

See more

How we coordinate a response to an outbreak.

Your obligations

Report sightings

You must report immediately if you:

• live in WA and have a box elder maple tree (on your property or street). The WA Government will check it for infestation by the borer.
• see signs of the polyphagous shot-hole borer in trees or plant material. Keep the material on your property.

If you suspect a pest or disease outbreak, report it. Even if you’re not sure.

Report to the WA Department of Primary Industries and Regional Development (DPIRD) through the MyPestGuide Reporter app or call the Exotic Plant Pest Hotline on 1800 084 881

For signs of exotic pests and diseases in imported goods, sea containers or parcels, call See. Secure. Report on 1800 798 636 or use our online form.

Follow the rules

Keep exotic dangerous pests and diseases out of Australia and follow domestic quarantine arrangements. Never ignore our strict biosecurity rules.

Import shipments may need to be treated and certified. Before you import, check our Biosecurity Import Conditions system (BICON).

Movement controls

A quarantine area remains in place across 30 local government areas in Perth, WA. This helps contain the spread of the borer. It also allows for surveillance activities to be undertaken.

The QA now encompasses two zones, Zone A and Zone B. The requirements for each zone are outlined on the WA DPIRD website.

You cannot move bark, potted plants, firewood, tree pruning's, logs, plant cuttings, mulch, timber, wood or wood chips out of the QA. These can act as a host and spread the beetle.

The polyphagous shot-hole borer does not affect grass. Lawn clippings can be disposed of as normal.

Check WA quarantine area requirements and map

About the pest

Polyphagous shot-hole borer is native to southeast Asia. The beetle is an agricultural and environmental pest. It has over 400 host species including amenity, native and horticultural production trees.

One of the main reproductive hosts in WA has been the box elder maple tree (Acer negundo).

The environmental impact of this species is likely to be high. Establishment of the pest in WA would have a significant impact on the urban tree canopy.

The adult female beetle is 2mm long. It tunnels into the tree’s stems and branches, causing damage and dieback. The borer spreads with the movement of infested trees, firewood, and green waste material.

See how to identify the polyphagous shot-hole borer (WA DPIRD).

The polyphagous shot-hole borer has a symbiotic relationship with the Fusarium fungus. This fungus is a food source for the beetle and its larvae.

The fungus colonises the tissue of susceptible trees. It’s likely the beetle and fungus complex, not the fungus alone, is what kills susceptible trees. Symptoms are wilting and dieback of tree branches and leaves, often starting in the upper canopy.

Female borers look for suitable host trees and may fly up to 400 metres. Spring and autumn are when it’s most likely to be seen, when it moves to new trees.

Trees in which the beetle can breed and multiply include maple, oak, plane, coral tree, avocado and willows.

Experience to date has shown that Australian and WA natives are not preferred hosts for PSHB. The overwhelming majority of all infested native hosts have been found in proximity to a highly infested preferred host.

Although globally PSHB is known to infest some fruit trees, the number of detections in fruit trees in WA has been less than one per cent of total infestations.

Euwallacea fornicatus and the fungi Fusarium euwallaceae, are listed on the National Priority List of Exotic Environmental Pests, Weeds and Diseases (Department of Agriculture, Fisheries and Forestry)