Wednesday, December 05, 2007

Emerald Ash Borer Arrives in Toronto

We knew it was on the way but didn't expect it to get here so fast. An article in the Toronto Star says that the Canadian Food Inspection Agency has found some ash trees infested with the Emerald Ash Borer (Agrilus planipennis) in the Highway 401/404 area. This is in the northeast section of the Don watershed so it definitely concerns us.

I remember attending a seminar last year on forest pests and the talk was about the Asian Long-horned Beetle (Anoplophora glabripennis) which infested a large area in northwest Toronto. The Emerald Ash Borer had been found in Windsor and was advancing steadily east. The thinking was that the beetle would probably arrive in Toronto in about 5-10 years so it's a surprise to find it so soon.

Once it infests a tree it eats into the sapwood. This is the part of the tree that transfers water and nutrients to the top of the tree. When this is gone the tree dies quickly. If this finds its way into the Don Valley this could have serious implications for our forests. Ash trees constitute about 10% of the trees in our forests so this could have a big impact on our forest canopy.

Efforts are underway to contain the outbreak but there is little anyone can do. They are very difficult to detect. As an introduced insect it has no natural enemies and no pesticides are known to kill it. Unless a miracle fix is found, we may be looking at a permanent change to our forest.

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