News

There has been recent media coverage about the impact of an invasive pest, Polyphagous Shot Hole Borer (PSHB) and the efforts to eradicate this beetle in Western Australia, including potential impact on macadamia which has been misreported. The beetle was first detected in the Freemantle region of WA in 2021 and as signatories to the national Emergency Plant Pest Response (EPPR) Deed, the AMS was informed and gave supporting evidence to the eradication response. Infestations of PSHB and the eradication activities are centred around the Perth/Freemantle metropolitan areas where it is affecting backyard and public amenity trees. You can see a map of the quarantine area and pest identification information here.

PSHB has previously been detected in other countries such as Israel, South Africa and the United States and specific research into the pest and its fungal symbiont in macadamia was conducted. Studies showed that like many other tree species singular macadamia trees can be susceptible to infestation, but that macadamia is not a reproductive host of PSHB and the fusarium symbiont had little effect on multiple macadamia cultivars. The media reports that this invasive pest has ripped through other countries causing significant damage is true for other tree species, but not macadamia. Work from our colleagues in South Africa who have been studying the pest since 2019 and the information from incursions in Israel, California and Hawai’i give us confidence that PSHB poses a low risk of infestation were it to advance outside of the quarantine area. Additionally, PSHB has been classified under the EPPR as a category one pest meaning that the eradication response is fully government funded, with no industry levies.

For those in WA it is important to follow quarantine restrictions and remain on the lookout for sign of PSHB within known susceptible trees such as:

1. Maple (Acer)
   
2. Black Locust (Robinia)
3. Coral tree (Erythrina)
4. Plane tree (Platanus)
5. Fig (Ficus)
6. Poinciana (Delonix)
7. Mulberry (Morus)
8. Willow (Salix)

 You can find more information about PSHB here.

Image credit: Polyphagus shot-hole borer in a maple tree. P Scanlon DPIRD, WA