Just two millimetres in size, the tiny shot-hole borer can kill a tree in two years.
At least 3,000 trees in Perth have already been destroyed in an effort to stop this pest.
Tunnelling through trunks and branches, they infect trees with a fungus that stops the transfer of water and nutrients.
Associate Professor Theo Evans, from the University of Western Australia, studies the behaviour and genetics of insects.
"It's about 1-2 millimetres in size, it's about a sesame seed. It attacks trees and it eats the wood, not directly but it has a fungus. The fungus attacks the wood and then the beetle attacks the fungus, and it can attack and kill hundreds of species of trees."
Concerns have also been raised within the community.
"Urban heatload is a massive, massive issue we're dealing with, with climate change. And then now we've got trees being impacted. I don't think we have a clear understanding of which trees are being impacted. It is impacting flowers and trees that give you honey, shade - all sorts of issues."
Originally from south-east Asia, the beetles were first detected in Western Australia in 2021.
Authorities say it is unknown how the beetle entered Australia.
Both the federal and state government have allocated money for a beetle eradication plan, with $20 million from the Albanese government and $4.7 million from the state government.
More than 160 full-time local employees are helping to implement the plan, which includes removing infected trees to stop the spread.
The invasive pest was previously thought to be contained within Perth's metropolitan area.
But, it's now been found in box elder, and, coral trees outside the quarantine zone.
Vincent Lanoiselet is the chief plant biosecurity officer from the WA Department of Primary Industries and Regional Development.
"Twelve trees have been found to be infested with the borer outside of the quarantine area. The good news is that the infestations are not very far from the boundary or the edges of the quarantine area, and also the detection were identified as part of a normal surveillance. We basically do a lot of work on the edges of the quarantine area to make sure that if the pest managed to escape the quarantine area, we can detect it very quickly and very fast to remove that infestation."
He says unfortunately there are no chemical controls available, to get rid of this pest.
They are engaging with international researchers that have more than 20 years of experience dealing with the shot-hole borer to find a collaborative solution.
The good news is that the infestation is not very far from the boundary or the edges of the area. And also the detection were identified as part of normal surveillance. We basically do a lot of work on the edges of the quarantine area to make sure that if the pest managed to escape the quarantine area we can detect it really quickly and act very fast to remove that infestation."
Associate Professor Theo Evans believes there could potentially be another way the beetle is spreading in Perth.
"So if people prune their trees, perhaps they have a tree branch near a power line. They will cut their branch off and take it away to be disposed of. And that might mean taking it outside of the quarantine zone."
He says the beetle can still spread even after an infected tree has been destroyed, as parts of the tree is turned into chips and then into mulch, which could then be transported and used in other locations.
"It's very concerning. It's bad in Perth. Perth already has a very low canopy and we will lose even more. But if you live in Sydney or Brisbane or Melbourne it might be worse. The beetle is probably better adapted to living on the eastern seaboard because it's more humid; and it also attacks figs. And figs are more prominent in the urban canopy in Brisbane and Sydney and it attacks London plane trees, which are very common in Melbourne. So they might lose 50 per cent or more of their urban canopy."
Authorities are now concerned the tiny beetle could spread to the east coast.
They are urging the public to check trees and report any sightings.
With the Spring breeding period fast-approaching, scientists are in a race against time to eradicate the beetle.
New warning signs are being put up across Perth, and the quarantine boundary is under review.
