Tuesday, 19 June 2007

EAB, The Real Deal!

EAB, The Real Deal!

Over the years there have been many real and imagined pests and diseases that have destroyed or threatened to destroy our forests. With this in mind I was somewhat jaded when the Emerald Ash Borer was put to the top of the list as the latest threat to our trees. Not again must have rolled off the tongues of every tree lover in North America.

After following the progression of this pest from infesting a few counties in the Detroit Michigan area to its current extent of five states and the Province of Ontario, something less civil should roll off the tongue! This pest may very well turn out to be the real deal, decimating all species of ash trees in areas that it becomes established in.

Emerald Ash Borer, Agrilus planipennis Fairmaire, is an exotic pest that was introduced accidentally into North America in the late 1990’s. The original infestation was probably the result of green wood in the form of packing materials that originated from the beetles home range in Eastern Asia. Whether it came from Russia, Korea, China or Japan is of little importance now. Logs infested with the larvae of the beetle were probably used to shore up shipping containers and were off loaded in Detroit. From there the adults, who can fly several miles when mature, found a welcome place to lay there eggs in North American ash trees.

It took several years before any one found the initial colonization and by then this prolific insect had developed a large population. The adults themselves feed on the leaves of ash trees but cause little damage. In late June to early July, they lay there eggs on the bark of ash trees usually in cracks crevices and fissures. The eggs hatch, burrow into the inner bark, the cambium layer and begin to chew their way though the vascular cambium layer in up to foot long serpentine feeding galleries. The larvae pupate and over winter under the bark of the trees and emerge as adults the following May or June. The beetles emerge from a small D shaped hole around 1/8th of an inch in size.

The tree is unable to survive the injury to its vascular system, starts to wilt and die back and will last only one to three years once infested.

The initial area of North America has now expanded to over twenty thousand square miles and includes five states and the Province of Ontario. In the areas where the outbreak has been identified over 12 million trees have been removed in an effort to stop the spread of the Emerald Ash Borer. Official estimates in Ohio expect the prolific pest will cost 3 billion dollars in the next ten years.

Recently additional infested trees have been found further east in London, Ontario. Wood and wood products appear to be the primary means of transportation over long distances. Quarantines have been set up in infested areas.

Do not transport firewood from areas where the beetle is known to exist. As a measure of the severity of this threat, note that national agencies have begun an ash seed library to prevent ash tree extinction if quarantine measures are not successful.

Contact your local ISA certified arborist for up to date local information. Be on the look out for unusual die back in ash trees.


Unknown said...

Looks like a good start Brad. Let me know what I can do to help out. Bob

Tree Care Canada said...


Emerald ash borer found in PA.