 Asian Long-horned Beetle
by Rosemary Tessier
On January 17th, we had possibly the most important speaker we have ever had at one of our meetings. Howard Stanley, from the Canadian Food Inspection Agency, spoke on the battle against the Asian Long-Horned Beetle in the Toronto area. Since the discovery of the ALHB in the Toronto/Vaughan area in September, 2003, Howard has been an ALHB project officer and has seen both the beetle and the battle at close quarters.
We have become accustomed, perhaps, to hearing about various insects and diseases that threaten our trees and other forms of vegetation, but this beetle is in a class all its own. It has no natural predators, not even in China, where it originates. It usually attacks healthy trees, not ones with existing problems. The larvae kill the host trees by tunneling within the trunk, disrupting the sap flow and weakening the tree until it dies. A tree with a 7 to 8 inch diameter will die within 2 or 3 years of infestation. Larger trees last longer, but once the beetle larvae are in the tree, there appears to be no way to save that tree. The insect attacks many deciduous trees: horse chestnut, willow, elm, birch, poplar, and others but its favourite is the maples. Under threat, therefore, are the maple syrup, hardwood, nursery and landscape industries, as well as our park and conservation areas, our roadside plantings, and many trees on private property
The pesticide Imidacloprid has been licensed in Canada to be used against the beetle, and Howard mentioned that even environmentalists in the Toronto area who are usually dead against any use of pesticides were willing to make an exception in this case because the beetle poses such a threat.
Unfortunately, this chemical does not seem to be really effective against the ALHB because the larvae burrow into and live in the very heart of the tree and the chemical does not reach them. If a healthy tree is injected with this chemical, it makes the wood unpalatable to the beetle, but does not necessarily kill it. Therefore, the insect will just move on to another, untreated, more tasty tree.
However, checking information on websites that Howard left with us indicates research is continuing on the chemical approach both in North America and in China, so in the long term, a pesticide may be found that is effective.
In the meantime, however, the beetle-fighters believe the only answer is to cut down and destroy not only an infected tree but any possible host trees within 400 meters of the infected one. Between September 2003 and March 2004, about 15,000 trees were removed from the infected area. All the wood from these trees was taken to a special site for grinding and chipping to a size not bigger than five-eighths of an inch. The experts believe no larvae or beetles can survive this fine a grinding and let’s hope they are right!
Howard mentioned that he had never before experienced so great a spirit of cooperation between the 3 levels of government (federal, provincial and municipal) as was demonstrated right from the start of the anti-beetle campaign. Clearly this is a sign that everyone who really knows about this insect is very alarmed at the possible consequences.
Since September 12, 2003, approximately 40 inspectors per day have been checking trees. Since trees can be infected at any level, it is necessary to check them both high up with ladders and buckets and at ground level. Even so, some infected trees are missed: when the potential host trees are cut down and examined before being destroyed, inspectors always find a few infected ones among the presumed healthy specimens. This is seen as another argument for cutting down the potential hosts in the 400 meter radius.
The infected area (called the regulated area) is roughly a square bounded by: Highway 401, Highway 27, Rutherford Rd. and Dufferin. Obviously, some people reading this newsletter are in the area and should be checking their own trees for possible infestations. Anyone in Toronto who cares about our trees should know what to look for:
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the insect has a shiny black body, about ¾ to 1&1/4 inches long with white spots and very long antennae with black and white bands
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signs of infestation on a tree are; exit holes in the bark, just under ½ inch across; oval wounds on the bark from egg-laying, which often leak sap; and saw-dust on the branches or at the tree base
If you think you have found an infested tree, call 1-800-442-2342.
If you live in the “regulated area” mentioned above:
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Do not move any branches or other tree material from your property and make sure anyone who does pruning on your property does not take away any of the wood. Call (416) 665-5055 to find out how to dispose of the wood. Howard mentioned the “nightmare scenario” of a property owner taking infected wood to a cottage in the Muskokas for firewood. Can you imagine what the beetle could do to cottage country?
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Check the exterior surfaces of your vehicle before you drive away from home. (The first beetle identified in our area was found on the windshield of a car in a parking lot).
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If you find and trap a beetle, put it in a container and into your freezer and call the 1-800 number above.
The following website gives more information: www.toronto.ca/trees/index.htm (2005-04-07) |
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