Box tree moths have infested Ontario and experts say more are coming. Here's what to do to protect your garden

An invasive moth species is on the rise in Canada and, if you've planted a certain shrub, it could stand to ruin your garden.

An invasive moth species is on the rise in Canada and, if you've planted a certain shrub, it could stand to ruin your garden.

The box tree moth, native to Asia and designated as an invasive species here in Canada, was first reported in the Greater Toronto Area in 2018. If left untreated, the moth's larvae destroy the only plant it is found on in Canada -- the boxwood shrub.

“Basically, they eat all the green material of the leaf and the tree starts to turn brown," Dr. Sandy Smith, professor in forest health at the University of Toronto, told CTV News Toronto. "It looks very raggedy."

 A second generation is hatched towards the end of summer, and the cycle repeats itself.

The shrubs, also non-native to Canada, are incredibly common in gardens across the country, Smith explained, largely because of their hardiness -- they stay green all year round -- and the ease with which they can be shaped into topiary.

Since the moth’s arrival in 2018, however, Ontario has declared an infestation. Quebec, Nova Scotia and New Brunswick, along with some U.S. states bordering Canada, have also reported a presence, prompting a warning from the Canadian government last week.

“This is very much an ornamental pest,” she said. “It’s not an issue of our natural landscapes.”