The Emerald Ash Borer is an insect native to Russia, China, Japan and Korea. Until 2002, it had never been seen in North America. It is suspected that they came on cargo ships. Originally found in ash trees only in Michigan, the Emerald Ash Borer has now been found in many areas in the United States and is fast becoming a nationwide problem. When a tree becomes infested, the canopy of the tree begins to thin because the borer destroys the water and nutrient conducting tissues under the bark. One-third to one-half of the branches may die in one year. Most of the canopy will be dead within 2 years of when symptoms are first observed. Healthy ash trees are just as susceptible as stressed trees. The borer can be controlled with a chemical injection. This injection method places the chemical directly where the insect is active without harming the tree. One application per year will kill the borer larvae and prevent further damage. It is important to note that treatment of trees showing no symptoms as a preventative is recommended due to the severity of the infestation and the lethal consequences of the Ash Borer.