The emerald ash borer, an invisible and invasive insect killer

The word 'emerald ash borer' has been sending shivers down our spines for the past ten years or so, with the disappearance of tens of thousands of ash trees, particularly in urban areas.
As the Canadian Food Agency points out, the emerald ash borer is an extremely destructive invasive beetle that attacks and kills all ash species.

A beetle is an insect, and the borer is a member of the Buprestidae family. The adult female lays her eggs on the bark. To develop, the larvae then penetrate the bark to reach the tree's living, sugar-rich cells, where they feed. Agrilus planipennis is native to Asia and eastern Russia, and has only recently been introduced to temperate North America.

What's going on? The insect ravages the living tissues of the tree's periphery, destroying the vascular vessels within. These are the 'veins' that supply the tree with water and minerals. No water, no life. The tree dies fairly quickly.

Does it become a potential hazard? Yes. Its decline will weaken the anchoring of its branches, and eventually its main trunk.

What can I do about it? By the time abnormalities are visible and obvious to the owner, it's usually too late. All ash trees in areas defined by the Canadian Food Inspection Agency should be inspected by an arborist. An insecticide can be a preventive solution. Trees with low foliage density, dead branches or dead bark peeling away from the trunk or branches, as well as tiny holes in the wood in the shape of the letter D, rounded downwards, are anomalies potentially indicative of the presence of the insect. Are my other trees in danger? For the moment, the insect's diet is limited to ash trees.

Give your ash trees the opportunity to grow in a healthy environment, in soil that's rich in soil improvers and well aerated, so they're not predisposed to weakening their health.