Polyphagous Shothole Borer

PSHB Origins

Polyphagous Shothole Borer beetle (PSHB, Euwallacea fornicatus) is a beetle native to Southeast Asia which is affecting various counties including USA, South Africa, Argentina and now WA. It is theorised that this pest hitchhiked its way to WA on untreated wooden products, subsequently spreading across WA in the similar manner (such as movement of infested wood as pruned trees or unseasoned firewood). This beetle is highly invasive and attacks a wide range of plants species (trunk diameter >2cm) with a global host list covering over 500 species.

PSHB affected  in Western Australia.

PSHB has a symbiotic relationship with a Fusarium fungus, cultivating it inside the plants as a food source, benefiting themselves and their larvae. In susceptible species, the fusarium kills the host plant by restricting movement of water and nutrients from their vascular vessels. This causes fusarium dieback in the host plant that eventually leads to plant death. The galleries created by the beetle, also causes structural damage throughout the plant. 

Signs of infections

PSHB are roughly the size of a sesame seed (~2mm), rendering detection extremely difficult however, they have common indicative symptoms:

  • 1mm perfect circular shotholes
  • staining/lesion
  • resin drops/gumming
  • frass noodles
  • sugar volcanos
  • black galleries

Please keep in mind that symptoms vary between different the plant hosts.

If residents notice any of the following symptoms on their property or public land, it is recommended to report it on the MyPestGuide app or contact the Pest and Disease Information Services (PaDIS) on 0893683080 or padis@dpird.wa.gov.au with clear pictures of the area of concerns.

How does it spread?

PSHB cannot travel for long distances, however they can be unknowingly translocated to long distance through the movement of infected dead and live wood (e.g. plants >2m diameter trunk, firewood, mulch).

What can you do?

  • Be cautious of moving out plants or wood products from the established   
  • When moving green waste to the tip, please ensure that they are not transported in open vehicles.
  • While pruning or gardening check your plants and branches for any signs of PSHB.
  • Do not move firewood long distances, including camping – buy it where you burn it.

Burning infected host plants or plant materials will not kill the beetle, it will encourage it to flee to surrounding trees.

  • Be on the lookout for any signs of infestations and report it.

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