Polyphagous shot-hole borer
785. Hon Dr Brad Pettitt to the Minister for Agriculture and Food:
My question without notice of which some notice has been given is to the Minister for Regional Development.
I refer to the 2023 research paper Cost effectiveness of spread mitigation strategies for polyphagous shot hole borer Euwallacea fornicatus (Coleoptera: Curculionidae: Scolytinae),which states:
A third strategy using a mix of chemical suppression and tree removal was also considered in light of new information about the pest's host preferences … this strategy was only slightly more expensive than using chemical suppression alone and could actually lead to eradication …
(1) Given the 2023 paper co-authored by Department of Primary Industries and Regional Development staff, why has complete tree removal remained the government's primary source of PSHB strategy to date?
(2) What is the government's current treatment of PSHB and, if it changed, when did this shift?
(3) Does the treatment in (2) include any chemical treatment and, if not, why not?
Hon Jackie Jarvis replied:
I thank the honourable member for some notice of the question. The question has been redirected to me. As the Minister for Agriculture and Food, I have carriage of biosecurity matters.
(1) The paper referred to was written early in the response when the potential host range of PSHB in Australia was not well known and was based on hypothetical options to mitigate impacts of PSHB if eradication was not feasible. It was based on desktop modelling of data available at the time and did not involve any field research into control methods. Tree removal or pruning remains the only proven method of eradicating PSHB in Western Australia.
(2) The National Management Group determined that PSHB was no longer technically feasible to eradicate in June 2025. As a result of this decision, DPIRD is now delivering an 18-month transition to management program. This includes surveillance and tree removals or pruning in strategic locations to slow the spread and manage the impact of PSHB.
(3) A number of chemical treatments are being used by local governments and other landholders in respect of PSHB management. Research into PSHB modelling, surveillance and controls is being delivered by the University of Western Australia, Murdoch University and Curtin University in partnership with DPIRD and funded by the WA government through the WA Agricultural Research Collaboration.
