Tent caterpillars are back, but it should be the last year of infestation

Since 2016, communities in northern Ontario have been overwhelmed by forest tent caterpillars. But provincial officials say this will likely be the last year our region sees the native insects in such numbers. (Jairus Patterson/CTV News)

Sault Ste, Marie — Since 2016, communities in northern Ontario have been overwhelmed by forest tent caterpillars.

But provincial officials say this will likely be the last year our region sees the native insects in such numbers.

“What we’re starting to see this year -- and we noticed it last year, as well -- is the weaning of the population,” said Dan Rowlinson, the provincial lead for the forest health monitoring program with Ministry of Natural Resources and Forestry.

"So we’re starting to see the population collapse naturally.” Rowlinson said forest tent caterpillar outbreaks typically last for three to five years before going dormant for a decade.

This is year five that the caterpillars have been active in northern Ontario.

According to Natural Resources Canada, the forest tent caterpillar can cause serious damage through the widespread eating of leaves and shoots.

Trees weaken by repeated defoliation and can be more vulnerable to various stresses, such as drought or infestation by other insects.

Forest tent caterpillar outbreaks are an expected part of boreal forest ecology and are considered a natural disturbance, just like fire. Widespread outbreaks have been recorded in much of the boreal forest since the 1930s.

The forest tent caterpillars defoliated 4.8 million hectares of Canadian forest in 2015. Large outbreaks among aspen trees have been recorded in Alberta, Ontario and Quebec.

We will have more on this story tonight at 5 and 6 on CTV news Northern Ontario.