Tent caterpillars gone but new insect poses threat

By Jennifer Bowman

Tent caterpillars are not a concern anymore, but ash trees in the Quinte region may be in danger, said Ontario’s forest etymologist.

Taylor Scarr is the provincial forest etymologist, who says said the vast number of tent caterpillars may have helped in the bug’s sudden decline.

There’s a natural virus that attacks the tent caterpillar after two or three years, killing the population, said Scarr.

“The higher the population of the tent caterpillars, the more rapid the virus will spread through it,” he explained.

For the past two years, the Quinte area was battling an unusual influx of tent caterpillars. It began causing concern in 2009 when 9000 hectares in and around the Quinte area were infested with the caterpillars. It caused concern because it was outside the area forest tent caterpillars usually infest.

A recent survey done by the Ministry of Natural Resources says the forest tent caterpillars are now gone.

The forests will regenerate themselves, said Scarr, but if too much damage has been done to a tree or the tree is under another stress, it will be more vulnerable to other insect infestations and stresses which could cause the tree to die.

There is another threat on the horizon – the Emerald Ash Borer. The insect has destroyed ash trees in central and eastern Ontario, but hasn’t reached the Quinte area yet.

They expect it to come to Quinte soon, if it isn’t already here, said Scarr. It’s east and west of Belleville.

The Emerald Ash borer destroys 99.9 per cent of the ash population, said Scarr. Most towns have 10 to 40 per cent ash trees, many of them planted after Dutch Elm disease destroyed the elm population.

About 25 per cent of the trees in the Bay of Quitne area are ash trees.

There isn’t really any way of preventing its arrival and it’s mostly by luck the Quinte area has escaped, he said.

“It’s a matter of luck or distribution,” said Scarr.

The Emerald Ash borer moves on its own, but also through people moving infested materials, such as firewood. Areas along the 401 are particularly vulnerable.

The Canadian Food Inspection Agency places quarantines on areas that are infested, hoping to slow down the ash borer’s progress.

“There are obviously people violating that quarantine because we are finding occasionally we are still finding new infestations that are a long ways from a known infestation which means that people are still moving infested material,” said Scarr.

Once they arrives, they won’t leave.

“If you replant the ash, the emerald ash borer will come back,” said Scarr.

That leaves the only alternative as planting different species of trees.

There is one up side.

Woodpeckers are benefitting from it, they eat the larva, said Scarr, but they can’t increase the woodpecker population enough to eliminate the ash borer.

As for the tent caterpillars, Scarr said it’s the kind of prediction they expect with climate change – more frequent insect outbreaks, more severe insect outbreaks, and insects in areas they usually wouldn’t be.

“We don’t know if it’s climate change or not, but it certainly is unusual to see it [tent caterpillars] in the Kingston Belleville area,” said Scarr.