DPIRD scientists are hoping to save these trees, some of which have already had limbs succumb.

FENCES have gone up around a chunk of Hyde Park to cordon off trees affected by the invasive polyphagous shothole borer as a new emergency chemical trial aims to eradicate the pest. 

Several trees have already had limbs removed as they were compromised by the tiny beetles. The borer excavates extensive tunnels through trees to cultivate fungus as a food source. 

Their farming disrupts the flow of water and nutrients and leaves branches withered, and can kill whole trees. Infested trees are also a constant source of more beetles.

The Department of Primary Industries and Regional Development is now starting trials of a chemical treatment to try to stop the borer. 

There are no registered chemical treatments to target the borer in Australia, but DPIRD obtained an emergency permit from the Australian Pesticides and Veterinary Medicines Authority to trial an injectable chemical derived from a type of soil bacteria that kills bugs.

It gets injected into the trunk and the tree’s own vascular system distributes the chemical to, hopefully, kill the borer. 

It’s been used on London plane trees by spraying the leaves before, and now an Australian company’s made an injectable form. 

The treatments take place across late May.

Since the borer was first spotted in East Fremantle in August 2021, it has spread rapidly to other Perth parks and backyard trees. 

In March the quarantine zone was expanded to cover almost all of Perth, from Hillarys to Wattleup.