News

Apr 06, 2023

Return of the tent caterpillar in northern Ontario

Tent caterpillar infestations are a problem in northern Ontario every few

Tent caterpillar infestations are a problem in northern Ontario every few summers and it looks like they could be returning this year.

People in Timmins said tent caterpillars are already swarming their properties and experts said it's a sign that another outbreak is on the way.

When the cold goes away, the north's native caterpillars come out to play and it appears countless thousands of forest tent caterpillars are making a grand return to the Timmins area this summer.

Swarms of them recently made a rowdy appearance at a local elementary school, which had to keep students indoors for recess while pest control dealt with the problem.

The caterpillars have been carpeting nearby roadways and residences and even feasting on one local woman's apple tree before she could "shoo" them off.

"Normally, you can see at the bottom of my tree," Tammy Hachey said.

"I have some foil there with Vaseline on it. So, that would … prevent the caterpillars from climbing the tree, but I didn't catch it early enough this time. So, hopefully the tree blooms again."

Sault Ste. Marie entomologist David Dutkiewicz, of the Invasive Species Centre, said tin foil is the perfect way to protect trees from climbing caterpillars and as long as they’re native trees, their leaves will grow back, if the insects manage to sneak a bite.

Dutkiewicz said forest tent caterpillars tend to converge in large numbers about every decade and that the region may be due.

"Judging by the reports we’re hearing, we are looking at, we’re moving into a forest tent caterpillar outbreak season, whether it's this year or the next year," he said.

Dutkiewicz said native trees are evolved to be regularly feasted on by these insects, but that binge-eating can eventually become unhealthy for the forest.

"Then it really depletes the sugars in the trees and it can cause other types of diseases," he said.

And forest tree caterpillars have a huge appetite.

They can just keep eating, and leave rows of trees picked clean of their leaves.

Poplar trees tend to be their favourite snack and the Ministry of Natural Resources and Forestry said their leaves tend to grow back stronger later in the summer.

Hachey said she’ll be prepared "and be ready with the foil and Vaseline."

The MNRF is expected to release an annual forest health report in the coming weeks, but said forest tent caterpillars typically aren't a concern.

Spruce budworms are more dangerous right now, MNRF said, since they munch on coniferous trees and can contribute to forest fires.