Polyphagous Shot-Hole Borer found in WA for the first time

Polyphagous Shot-Hole Borer.
Camera IconPolyphagous Shot-Hole Borer. Credit: Pia Scanlon

A potentially-devastating tiny beetle with potential to cause major issues for WA’s highly-valuable avocado and citrus industries has been detected in Australia for the first time.

Biosecurity experts are in overdrive after the Polyphagous Shot-Hole Borer was confirmed in a backyard maple tree in East Fremantle this month.

Department of Primary Industries and Regional Development chief plant biosecurity officer Sonya Broughton said the borer was detected by a resident who reported signs of dieback and dead branches in their maple tree through the department’s MyPestGuide Reporter app.

Native to South East Asia, the exotic borer attacks a wide range of trees, but the top five to check are maple, oak, plane, coral tree and avocado.

“If established, the borer would have a significant impact on a number of industries including avocado, citrus, forestry, nursery and gardening,” Dr Broughton said.

“The borer can spread by flying up to 400m to neighbouring trees or by the movement of infested firewood and green waste material, which is why it is important that local residents do not remove any wood or green waste from their properties, unless it is through an approved council collection, as we continue our tracing and surveillance.”

The department has asked residents to check trees and report any signs of borer damage and wilting, and is also undertaking surveillance in the East Fremantle and Fremantle areas to determine the spread of the borer.

Local residents have been urged not to remove wood or green waste material from their properties unless it is through an approved council collection to help contain potential spread.

Polyphagous Shot-Hole Borer.
Camera IconPolyphagous Shot-Hole Borer. Credit: Pia Scanlon

Dr Broughton said the borer and their larvae would be hard to spot as they spent most of their lives inside a tree, however there were a number of symptoms to look out for that indicates the borer could be present.

“These include multiple entrance holes on the trunk or branches that are approximately the size of a ballpoint pen tip, frass extruding from the tree and crystalline foam (sugar volcanoes) exuded from the entry holes,” she said.

“Other signs to look out for are thick resin or sap on the tree branches or trunk, dark brown to black staining of the wood around entrance holes and dying branches and tree death.”

WA Agriculture Minister Alannah MacTiernan said the community had been “exceptional” at supporting DPIRD’s emergency response efforts in the past.

“The WA community has been exceptional at supporting our emergency response efforts as we saw earlier this year when we were able to successfully eradicate Queensland Fruit Fly in the Perth area,” she said.

“A strong biosecurity system is critical to growing our State’s economy and regions by protecting our $11 billion agriculture, aquaculture and fisheries industries and our natural resources.

“Each year we are seeing more animal and plant pest and diseases incursions across our State and we need to be well prepared to act quickly.”

The surveillance effort is backed by the State Government’s recent $15.1 million boost to strengthen biosecurity management and responses to pest and disease incursions.

To find out more about Polyphagous Shot-Hole Borer and the symptoms to look for in backyard trees, agric.wa.gov.au/borer

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