Emerald ash borer could soon be attacking Thunder Bay trees

It's only a matter of time before the emerald ash borer, a hungry, invasive beetle, arrives in Thunder Bay, according to city forester Shelly Vescio.

The beetle has been confirmed in Duluth, Minn., which is about 300 kilometres southwest of the city — the closest confirmed site yet of the invasive insect.

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Vescio said the insect will eventually make its way to Thunder Bay. The beetle usually spreads via firewood transportation, but she said firewood inspections at the Canada-US border could help slow down its arrival.

"We've yet to detect it, but knowing that it's in Duluth, if it's not here already, it's just a matter of time. The border is the place is has to be stopped," she said. 

Vescio said the beetle could have a major impact on the forest canopy in Thunder Bay.

"It's inevitable. And, when it gets here, it's going to be a very costly management program. We're going to lose all of our ash trees," she said.

Thunder Bay has about 6,500 ash trees, making up about 25 per cent of the total tree canopy.

She said there is a chemical that can be injected into ash trees to save them from the beetle, but it costs about $200 per tree. Even then, it's a cheaper solution than planting new ones, although the city no longer plants ash trees.

Vescio said because of the cost, the city would not be able to treat every ash tree. The city did a tree inventory this year - the results of which should be ready soon. Vescio said that study will help to identify which trees to save.

The beetles can infect both healthy and unhealthy ash trees, which can live to be more than 100 years old.