DPIRD entomologist Elsie Kinniard (right) checks damage caused by the exotic pest Polyphagous Shot-Hole Borer.

DEPARTMENT of Primary Industries and Regional Development staff removed the box elder maple tree at the centre of an exotic borer scare in East Fremantle last week – right down to the roots (“Deadly borer finds Aussie foothold in East Freo,” Herald, September 18, 2021). 

The polyphagous shot-hole borer hasn’t been detected in Australia before, but in California where it’s established the US Forestry Service expects it will eventually wipe out 27 million trees.

It is also having a noticeable effect on Johannesburg’s remarkable urban forest, with fears the South African city will eventually suffer worse pollution and hotter streets as a result of the dramatically thinned canopy.

DPIRD entomologist Elsie Kinniard, who oversaw the removal of the tree, said the campaign to track down any spread of the shot-hole borer could take months.

Officers would focus on a 400-metre radius around the Dalgety Street property – the insect’s flight range – and if any further infestations were discovered another radius would be added, until it’s outermost limit had been detected.

Favourite host

The presence of the borers doesn’t necessarily result in the removal of a tree unless it poses a significant risk to safety or the spread of the pest, but homeowner Joanne Taggart unfortunately chose it’s favourite host for her backyard and her maple is beyond saving.

The department has asked residents to check for any bored holes about the size of a pallpoint pen in their trees and report anything unusual via the MyPestGuide app or to the Pest and Disease Information Service on 9368 3080 or padis@dpird.wa.gov.au

by STEVE GRANT