This is the notorious emerald ash borer, responsible for the death of thousands of ash trees all through the eastern US into Canada as far north as Ottawa. It was thought that our cold winters would kill the larvae, but that hasn't happened. Last winter (2012-2013) the dying ash were particularly easy to pick out as hairy woodpeckers were busy feeding on the ash borer larvae and the trees with the bark scaled off by the woodpeckers were noticeable across the region. The woodpeckers don't kill the trees, the larvae of this pretty beetle do. In fact the woodpeckers probably helped to control at least some of the insects, though not nearly enough to make any difference.

We searched about 40 ash trees in a greenbelt area in the east end today, and found three adults, all on one tree. The other trees all showed extensive damage. We saw many of the distinctive D-shaped exit holes, and also the 'galleries' caused by the larvae under the bark, as they feed.