Just four months into a new chemical trial, the City of Canning believes it has found a way to combat the polyphagous shot-hole borer. In the trial, 131 infested trees were injected with a small vitamin-like capsule containing insecticide and fungicide, and are now showing no signs of live beetles or larvae. The tiny invasive tree-killing pest was detected in 2021 and has since led to the destruction of more than 4,000 trees in the Perth metropolitan area as the state government follows an elimination strategy. …City of Canning Mayor Patrick Hall said the method did not pose a risk to wildlife, as the trees absorbed the capsule. “The insecticide is a very small dose, injected deep into the tree, and then we put a plug behind it to make sure it can’t leach out. And that traps the insecticide inside the tree — that then goes up the vascular system.”