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Holey trees make a stir near Cowichan Bay

Specialists believes cause is insects and climate change
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What started as holes in the leaves of some of the deciduous trees on the property of Cowichan Bay’s Jennifer Lawson has quickly led to some of the trees being as bare as skeletons.

Lawson said the problem began about two weeks ago on some of her maple trees, but it has spread to Garry oak, fruit trees and some other species all through the area of the Cowichan estuary.

“I’ve lived here for 16 years and I have never seen anything like this,” she said.

“I think it may be connected to the increasing drought conditions that have been hitting the Valley in recent years.”

Davey’s Tree Services’ David Hunter, who is a consultant on tree diseases for the company, said he has seen a “ridiculous” amount of leaves being eaten through on a variety of deciduous trees in the area this year.

He said, while he hasn’t seen the trees that Lawson is concerned about, he thinks it may be caused by the predation of aphids and certain species of moths.

“It’s an unusual occurrence, but we have been having an increasing number of milder winters recently,” Hunter said.

“That has led to many insects, like aphids and some species of moths, now over-wintering in the trees’ bark and leaves and they don’t die because of the warmer temperatures, which means there are a lot more of them than there used to be.”

But Hunter said most trees are fairly hardy and can survive such onslaughts by predatory insects.

“Many species of trees can lose up to 80 per cent of their leaves and still survive,” he said.

“Trees have evolved to survive alongside insects.”



Robert Barron

About the Author: Robert Barron

Since 2016, I've had had the pleasure of working with our dedicated staff and community in the Cowichan Valley.
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