This year, we took the plunge, and spent about $650 to get it injected with some sort of magic elixir that will inoculate it for 2 years. That's a lot of green (a pun!). Apparently prices in Canada are so high because many of the alternative pesticides have not yet been approved. By the time they are, it may be too late. In any event, here's what it looked like right after it was injected. The plugs have since been removed.
We love our treed neighbourhood, so we were trying to dull the sharp wallet pain by thinking about how we were doing our part to preserve the look of our street, our property value, etc. etc.
Then we witnessed the destruction in action. An ash tree a few houses down from us got attacked, and showed its rapid decline this weekend.
I suspect that one is beyond saving now. Considering the appeal of a mature tree, and that removing one of that size can cost a few thousand dollars, I feel a little better about the cost of saving ours now.
I wonder if in a few years all the borers will be gone after the last un-protected ash goes, and we can return to normal?