The Glengarry News - Glengarry Supplement
Ash borer: Battling a tiny threat
The emerald ash borer is a forest pest native to Asia that has killed millions of ash trees throughout North America.
Due to its major economic and environmental threat, the Canadian Food Inspection Agency has prohibited the movement of firewood and any material made from ash trees outside of designated areas under an Infested Places Order.
All of Eastern Ontario falls under the restrictions.
There are tree treatments on the market, however, the insects
seem to be unstoppable as they continue to wreak havoc.
The hope is that by stopping the movement of firewood, the spread of the bugs can be impeded.
What can the average person do? Learn how to identify the borers and infested trees, as well as which host trees they target. Don’t move infested wood material from the regulated zone to new areas. Firewood should always be obtained locally and burned locally.
If you see a borer or signs of infestation, call the Ontario Ministry of Natural Resources and Forestry at 1-800-667-1940 or the Canadian Food Inspection Agency at 1-800-442-2342. Report sightings to the toll-free Invading Species Hotline at 1800-563-7711 or visit EDDMapS Ontario to report a sighting.
The emerald ash borer attacks both healthy and stressed Ash trees when its larvae tunnel through the tree’s vascular system which delivers water, nutrients and sugars throughout the tree.
The bug was first discovered in North America in 2002. It is thought to have been shipped to Canada in untreated wooden packaging materials. The range of the borer in Ontario is rapidly expanding through the movement of infested materials.
It has no known natural enemies.
Once infested, mortality of ash trees is nearly 100 per cent.
How to Identify Emerald Ash Borer
Trees appear to be thinning at the crown, dead branches and yellowing of leaves. Adults emerge from a D-shaped exit hole between mid-May and late June. Adults are metallic bluegreen. Bodies are narrow and 8.5 to 14 mm long. Larvae are a creamy white colour with a light brown head.
In Canada, beginning in late May and early June adults of the emerald ash borer emerge by chewing out through the bark of the host tree, creating a characteristic D-shaped hole.
The adults feed on the host foliage for a period of up to two weeks prior to mating and egg laying. Males locate females for mating by a combination of pheromonal and visual cues. Females lay their eggs in bark crevices or under bark scales on the branches and trunks of the host trees. Larvae hatch from the tiny (0.6 by 1.0 mm) disk-shaped eggs after one to two weeks of incubation, depending on the temperature. The newly hatched larva tunnels out the bottom of the egg, down through the layers of the bark until it reaches the interface between the bark
and the wood. There it feeds and excavates an S-shaped tunnel, where it grows and develops through four moults of its exoskeleton. The larva then chews a tunnel into either the wood or the bark, forming a chamber in which it will pupate. The larva doubles over on itself in the chamber and becomes a Jshaped prepupa. This is the stage in which most of the population overwinters in southern Ontario. A small number of larvae in southern Ontario, and a greater number in more northerly climates, don’t reach maturity and require a second winter to complete development. In spring, prepupae transform into pupae in these chambers and eventually into adults.
On average, prepupae of the emerald ash borer are able to withstand minimum temperatures of about –30°C, in part through the production of antifreeze compounds. Underbark temperatures where the prepupae overwinter are often higher than air temperatures. These two factors suggest that the beetle may be able to survive in most areas where ash occurs naturally or has been planted.
In more northerly climates, the preponderance of a two-year life cycle will slow population increase and natural spread.
The French common name is
Agrile du frêne. The scientific name: Agrilus planipennis Fairmaire. In Canada, emerald ash borer has been detected throughout the eastern counties, southwestern Ontario, Ottawa and nearby counties in eastern Ontario, and in Sault Ste. Marie and on Manitoulin Island in northern Ontario.
In Québec, the beetle has been found in the vicinity of Carignan and nearby municipalities, in Gatineau, on Montreal Island and in Ville de Laval. The pest has also been confirmed in 21 states in the United States.
The areas in Canada currently regulated for emerald ash borer can be found on the Canadian Food Inspection Agency’s website. A map showing the current North American distribution of the emerald ash borer is available from the Cooperative
Emerald Ash Borer Project. Principal hosts are Green ash, white ash, black ash, pumpkin ash and blue ash. In northeastern North America, five species of native ash have been attacked by emerald ash borer.