Tent caterpillars sweeping through Boreal forest

Jun 7, 2013 | 12:54 AM

A tent caterpillar outbreak just north of Prince Albert could be ground zero for a province-wide invasion.

Several pockets of hardwood forest near Christopher Lake, Emma Lake, and Montreal Lake have become overrun with the insects during the last week.

“This is sort of an epicentre of areas that have been defoliated so far that we’re aware of at this point in time,” said Rory McIntosh, provincial forest etymologist and pathologist for the ministry of environment.

“Some of the reports I’ve heard from the folks up at Emma Lake say that last Thursday they saw maybe two or three caterpillars but by Friday or Saturday there were thousands, tens of thousands of them everywhere,” he said.

That’s the scene that unfolded on Ed Moretto’s property.

The long-time resident of Emma Lake said he first noticed them on Wednesday night when his kids were playing with couple caterpillars that they found in the yard.

But the situation quickly got out of hand. “On Thursday I noticed dozens and on Friday morning there were hundreds … and Saturday I had thousands crawling on my house,” said Moretto.

They have become a nuisance for his family, in addition to completely defoliating the area’s white poplars. “It takes a few hours every day to clean up and we can’t use our yard, the kids can’t even jump on the trampoline,” he said, adding it gets covered with a layer of droppings every day.

Bevin Andres, with Ever Green Arborist in Christopher Lake said the damage, although localized within several smaller pockets, has been extensive.

“They defoliated the poplars within a day, they really came on hard and fast,” said Andres. “They won’t kill a poplar tree in one attack but it weakens it and the weak ones will die from it but poplars will survive a couple years of being defoliated,” he continued.

McIntosh said the poplars aren’t even the caterpillars’ preferred food source. “Depending on their population density sometimes what they’ll do is stray from their preferred [food source] and start to feed on other hardwood species but trembling aspen really is their preferred host.”

McIntosh said his team is working very closely with their colleagues in Alberta to track the progression of the tent caterpillars.

“We realize that this likely part of a much, much larger regional outbreak, we know there’s an outbreak building in Alberta too,” said McIntosh.

The province will conduct their annual aerial surveys in the next few weeks. These should give McIntosh and the ministry a better idea of the presence, distribution, extent and severity of the outbreak.

sleslie@panow.com

On Twitter: @_seanleslie