Deadly Pest Killing Ash Trees in City

By Debra Black
Toronto (December 5, 2007)- The highly destructive and invasive emerald ash borer- which kills only ash trees- has been found for the first time in Toronto. And according to city officials it could have a devastating impact on the city’s urban forest- killing hundreds of thousands of ash trees on city and private property. The city has about 30,000 ash trees on its streets, said Ubbens. But there are also hundreds of thousands of ash trees in its parks, ravines, and on private property.


The eggs of the beetle are tiny- almost microscopic- and once hatched, the larvae eat away at the connective tissue of the ash tree, ultimately killing it. It’s destroying a whole genus of tree, Ubbens said. “We’re talking about hundreds of thousands of trees dying in a period of four or five years.”
The CFIA said that for the moment the infestation seems to be contained to less than 100 trees in the area. The trees have likely been infected for a number of years, said Ken Marchant, a specialist in the emerald ash borer at the agency. Sadly, he said, little can be done to prevent the spread of the beetle since no known pesticide can be used to kill it. All officials can do is try to slow down the spread of the infestation by restricting movement of the ash trees and firewood.
The beetle first came to North America from Eastern Asia in the 1990s in wooden packing materials. It was first found in the Detroit area in 2002, Marchant said. Since then it has spread, eventually infesting trees in Canada in the Chatham-Kent area as well as Essex, Elgin, Lambton, Middlesex and Norfolk counties. Now it has made an appearance in Toronto.
The beetles are capable of flying from tree to tree up to a radius of about 10 kilometres, said Marchant. They tend to stay in one area until all the ash trees are dead. Then they move on. It is believed that the emerald ash borer has killed more than 20 million ash trees as it has traveled across the countryside.
The city’s infestation was first detected after an inspector with the Ontario Ministry of Natural Resources noticed some dead ash trees. Tests conducted by the CFIA revealed that the beetle was present. “Emerald ash borer is a serious tree killer,” said Marchant. “But by the time you find it, it’s too late.”
For the full article, visit the Toronto Star.