Emerald ash borers killing trees in Sudbury, Ont.

The emerald ash borer hasn't been in Sudbury, Ont., long, but the insect is already changing the local landscape.

Emerald ash borers are green beetles native to parts of Asia that can devastate ash trees.

Last year, Sudbury's Science North had to cut down ash trees the insects killed, and now the city is also removing infected trees on public property.

Jennifer Babin-Fenske, the city's climate change co-ordinator and an entomologist, said it's game over if emerald ash borers settle in an ash tree.

"If it's in the area, your ash trees are going to die," she said.

Babin-Fenske said females lay their eggs on the trees' bark, and it's their larvae that borough through the trees and chew on the wood.

"They're moving all around the outside of a tree," she said.

By chewing through the bark, the larvae cut off the tree's food supply and it eventually dies.

Babin-Fenske said one way the insects spread to new areas is through firewood. That's why it's important for campers not to buy or cut firewood in one area, and use it somewhere else, she said.

She added diversity, especially in tree species, is especially important with such a destructive invasive species. Because they only target ash trees, if a city has other species of trees in its parks, for example, they at least won't be affected.

Babin-Fenske said there are some insecticides that work on emerald ash borers, but they have to be injected in the trees, and before an infestation takes hold.

With files from Markus Schwabe