It will be interesting indeed to see what sort of strategy the city comes up with in response to the nightmare threatened by the emerald ash borer.
A lot of ash trees were planted in Canadian cities after another beetle, the elm bark beetle, devastated many urban streets in the late 1960s and 1970s. City hall estimates Guelph has 10,000 ash trees along its streets, as well as many more on private property and in parks, woodlots and conservation areas. It boggles the mind to think they could all be gone within 10 years “unless significant measures are taken to mitigate the spread” of the emerald ash borer, as city hall is warning.
A new city report grimly states that tree removal has to be considered as an option in any cost-benefit analysis of how to deal with the situation, given that the only chemical measure approved for use against emerald ash borer is expensive and is only effective for two years or less. City hall says there’s no long-term evidence that this chemical alone can defeat the spread of the half-inch-long, iridescent green beetles, which are native to Asia and now causing havoc in North America.
It’s not the adult beetle that do the tree damage. The beetle’s one-year life cycle starts with eggs being laid in bark crevices from late May to the end of July. After the eggs hatch, the larvae bore in and under the bark layer, growing to an inch or more. The larvae overwinter under the bark, grow into adults the next spring, and the cycle repeats. The larvae interrupt the flow of water and nutrients of the tree, causing great stress and eventual failure.
The federal Canadian Food Inspection Agency has regulatory control over the emerald ash borer and has imposed a firewood movement ban on many parts of southern Ontario, including Guelph. While the adult beetle flies well, human movement of infected firewood, logs and nursery stock is seen as the most common way emerald ash borer has been spread. But although the emerald ash borer is federally regulated, neither the federal or provincial government has offered any direct financial support so far to affected municipalities to help in the struggle against the destructive beetle, the new city report says.
It’s not acceptable for this lack of support to continue, given the chilling scope of the problem.