The shot-hole borer has been detected on the WA holiday island of Rottnest.(ABC News: West Matteeussen)
The tree-killing shot-hole borer has been detected on Rottnest Island, where less than 10 non-native trees have been killed or infested by the beetle.
The detection raises concerns for the island's long-established Moreton Bay fig trees.
Mulch is now being treated before being sent to Rottnest to prevent the pest being transported to the island.
The shot hole borer has been detected on Rottnest Island and has already destroyed several trees, raising concerns for the island's long-established Moreton Bay figs.
Tourism Minister Reece Whitby confirmed the arrival of the invasive pest on the WA holiday island, off Perth, in response to a question during a budget estimates hearing in state parliament on Tuesday.
The tree-killing beetle has spread across the Perth metropolitan area,and there is a nationally-funded effort to stop it breaking out into agricultural areas and other parts of the country.
The wood-boring beetle beetle has impacted the tree canopy in Kings Park and Hyde Park.(ABC News: Nicolas Perpitch)
On Friday, the pest was detected in the City of Wanneroo, in Perth's north, for the first time, after previously mainly being found in the southern and central metropolitan areas.
The WA government recentlyconceded it had lost the multi-million dollar fight to eradicate the shot-hole borer, instead shifting its focus to managing it.
Most of the trees on Rottnest Island are native, which the beetle does not target.
However, Mr Whitby told budget estimates less than 10 non-native, or exotic, trees had been killed or infested by shot-hole borers.
There are fears for the Moreton Bay Fig trees on Rottnest Island after the beetle infested trees at Kings Park.(ABC News: West Matteeussen)
There is particular concern for the island's long-established Moreton Bay fig trees.
"We're very mindful of ensuring that they are protected," he said.
"There's a lot of work about that given that they are not natives and I guess they are more susceptible."
Moreton Bay fig trees have already been removed from Perth's Kings Park and Hyde Park as part of efforts to eradicate the polyphagous shot-hole borer.
The shot-hole borer devastated trees on the islands at Hyde Park.(ABC News: Nicholas Martyr)
According to the Department of Primary Industries and Regional Development, there have been no confirmed detections outside of the Perth metropolitan area.
But the national biosecurity strategy to deal with the pest is currently in transition from eradication to management, in recognition that it is not possible to wipe them out.
It is suspected the destructive beetle came to Rottnest Island in a batch of mulch from the mainland.
Thousands of South Australia's trees and some crops will be threatened if a tiny beetle makes its way across the state border from WA.
All mulch is now being treated before being sent across to the island.
"It's being monitored very closely, and we haven't seen any further issues, " Mr Whitby said.
Trees native to Rottnest Island were already being propagated in a nursery to try and re-establish the woodland that once covered much of the island.
Mr Whitby said that would continue and will be part of the re-planting of trees impacted by shot-hole borers.
Topic:Disaster and Emergency Response