Horticulture, forestry industries concerned as State waves the white flag on polyphagous shot hole borer

WA’s horticulture and forestry industries are bracing for potential costs in the billions after the State Government gave up on eradicating polyphagous shot-hole borer and switched to trying to managing the pest. The small beetle, which burrows into trees and infects them with a fungus, has wreaked havoc across the Perth metropolitan area since it was first detected in 2021 — infecting about 4800 trees. The Cook Government last week announced it could not eradicate the pest and said the Department of Primary Industries and Regional Development would instead transition to a management phase to minimise its spread and impact. It came after the National Biosecurity Management Group — responsible for the strategic direction of exotic plant pest and disease eradication programs — determined it was no longer “technically feasible” to eradicate it from WA due to the “difficulty of detection and lack of defective chemical treatments”. The only way to stop the borer — which tunnels into trunks and branches of a wide range of species — is to remove infected trees. While the pest has so far only affected trees in Perth, it also poses a risk to a range of horticulture crops including avocado, mango, pear and apple, and has a taste for native paperbarks and eucalyptus. WA Agriculture Minister Jackie Jarvis said she hoped research could come up with new solutions to eradicate the borer but it might be a biosecurity threat that WA farmers will have to learn to live with. “The hard work we have done over the last few years has been incredibly successful in keeping the borer out of our regional locations and the people of Perth will still be asked to report possible sightings of shot-hole borer,” she said. “Part of the transition to management is to actually slow the spread and we obviously hope that science can come up with an answer before it becomes a concern. “The fact that a national management group have said it’s no longer technically feasible to eradicate indicates that we may have to learn to live with this pest in the near future.” Shadow agriculture minister Lachlan Hunter called for Ms Jarvis to resign, labelling it “the most shameful chapter of WA’s biosecurity history”. WA industry representatives and stakeholders were advised of the National Management Group decision on June 19. The admission that it is not currently possible to eradicate the borer has horticulture experts concerned about a national spread. “This is tragic news not just for WA, but potentially for native trees, towns and cities, and the horticultural industry across the entire country,” Invasive Species Council policy director Carol Booth said. Warren-Blackwood MP and shadow forestry minister Bevan Eatts said the forestry sector in particular was “gravely concerned”. “The State Government needs to throw everything at this to make sure this pest does not spread into regional areas,” he said. The Australian Forest Product Association — which represents the entire supply chain from producers to processors — issued a damning statement “lamenting” the State Government’s decision to move to a management phase. AFPA chief executive Diana Hallam said the “insidious” pest now also posed a risk to the productive capacity of the country’s blue gum plantations and had the potential to destroy Australian forests. “The likelihood it spreads from metro Perth to other parts of the country has increased as a consequence of the decision to move from an eradication to a management strategy,” she said. “The cost borne by our industry and other stakeholders, like local councils, to prevent its spread and manage its risk will unfortunately likely increase.” Ms Hallam pointed to countries where the borer was already established, such as South Africa and California, where the losses of cost and management were in the “billions of dollars” — footed by local government, horticulture, forestry and environmental groups. The WA Government implemented and funded a three-year response plan, with costs borne by the Federal Government, and last week set aside $26.5m in the State Budget to bankroll projects to help prevent the pest’s spread. Research is about to start on projects that will potentially help protect WA’s agriculture industries from the borer, with $26.5m in the State Budget and the WA Agricultural Research Collaboration also investing more than $2m across three new projects. WA director-general for biosecurity Mia Carbon said the fight against the pest would go on, and plant movement restrictions will remain in place across the Perth metropolitan area. “In any biosecurity response, sometimes you get to the point where we say that the cure is now potentially worse than living with the the problem long term,” she said. “We’re better to find long term management strategies that minimise the impact.” Manjimup avocado farmer Vic Grozotis said farmers had accepted the announcement but were concerned they would end up bearing the cost of management down the track. Mr Grozotis said he was “really hoping” it did not make its way to the South West. “We definitely need to be vigilant, to make sure it does not spread within the industry,” he said.