You may remember spongy moths, the invasive species formerly referred to as LDD moths, that caused a headache for many GTA municipalities last year.
Experts say those hairy insects are making a comeback in southern Ontario, with just as big of an appetite for local trees.
“It now lives in Ontario. It’s a resident. It’s here now to live with us for good,” says Natural Resources Canada research scientist Chris MacQuarrie.
MacQuarrie says outbreaks of the caterpillars can happen every seven to 10 years, which each outbreak spanning up to three years.
“Every once in a while we get these giant outbreaks where they defoliate millions and millions of hectares and people notice them.”
Spongy moths typically lay their eggs on the bark of different types of trees including oak, maple and birch, on city property and in private yards. When their eggs hatch in the spring, the insects ascend the trees, feeding on new foliage.
A number of GTA municipalities including Toronto and Mississauga were extensively impacted in 2021. Parts of Toronto including Scarborough, North York and Etobicoke saw the most damage.
Dan Giannobile, who lives near the Scarborough Bluffs, remembers all too well.
“The droppings just make the deck a mess. We just can’t use it.”
“It’s a real impact. You can’t have people over, you can’t have the kids playing out in the yard,” he said.
According to the province, defoliation caused by the caterpillars increased from 586,385 hectares in 2020 to almost 1.8 million hectares in 2021. This is more than three times the size of Prince Edward Island.
“This year’s strategy is basically to employ an aerial spray by helicopter, where we’ll be spraying several different pesticides,” said Joel Harrison-Off, a forest health care inspector with the City of Toronto.
“This is the second or third year of high levels of spongy moths and they have done a lot of damage to both private trees and city-owned trees.”
Harrison-Off says the city’s spray campaign will begin in mid-May with efforts focused most on North York and Scarborough. For other municipalities like Mississauga, spraying will also begin in a few weeks.
Experts say residents can also take matters into their own hands and wrap burlap around their trees.