❓ Dr. Pettitt questions the government's PSHB strategy, focusing on tree removal over other methods suggested in a 2023 paper. The Minister responds, explaining the shift from eradication to management due to the pest's spread and ongoing research into control methods.
AnsweredQoN 785Legislative Council
QuestionView source ↗
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?
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?
AnswerView source ↗
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.
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.
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