Leaf-mining weevil killing P.E.I. beech trees

Several beech trees on Prince Edward are showing signs of an invasive species called the beech leaf-mining weevil.

These weevils consume the leaves of beech trees, which can disrupt the flow of nutrients and kill entire trees. 

Simon Wilmot, coordinator for the P.E.I. Invasive Species Council, said it's uncertain how much damage the weevil will cause to the Island's beech trees, but "it can spread easily."

The weevils look like small black beetles about 2.5 millimetres long. They originate from Europe but it's suspected they've been present in Nova Scotia since around 2007, said Wilmot. 

There were a few reports of the weevil in P.E.I. last year, but the number of sightings has now increased.

How'd they get here?

It's hard to be certain where the weevils came from, Wilmot said.

"It could have hitchhiked here in a number of different ways but most likely it came over in some firewood from Nova Scotia," he said.

"This particular weevil spent the majority of its life in the cracks and crevices of barks of different trees. So it can be moved easily by human activity."

Though weevils can travel in the bark of a number of different types of tree, there are no signs yet that they eat the leaves of any tree other than the beech. 

The Invasive Species Council currently has reports of the weevil's presence in Charlottetown, Stratford and the Belfast area. 

No effective way to fight it

Wilmot said unfortunately there is no effective way to fight against the weevil. 

There is an environmentally friendly insecticide called TreeAzin that can be injected directly into beech trees and kill weevil larvae. However, the insecticide must be injected on a regular basis and therefore would not be an efficient large scale solution. 

The Invasive Species Council is not yet certain of how many trees on the Island have already been affected by the weevil, but Wilmot said "it is worrying how quickly [the weevil] can multiply."

Beech trees on the Island are already struggling with beech canker disease, so this new issue of weevils could potentially be very problematic for the beech tree population, he said.

Spotting the damage 

Weevils in a beech tree are not hard to spot, said Wilmot.

"The leaves will look scorched or wilted, kind of yellowy-orange," said Wilmot.

"You'll see sort of blotchy kind of holes in their leaves." 

As the weevils grow into adults, Wilmot said they will also start eating a leaf from its outer edges.

The Invasive Species Council asks anyone who spots weevil damage on beech trees to contact them. Islanders can reach the council through their Facebook page, website or by emailing peiinvasives@gmail.com. 

More from CBC P.E.I.