The emerald ash borer is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. In the years since its discovery, the beetle has spread across North America. The beetle feeds exclusively on ash trees, killing virtually every ash within 3-5 years of infestation. Since 2002, the emerald ash borer has killed more than 40 million ash trees in 25 states. It has cost municipalities and property owners hundreds of millions of dollars to remove, treat, or replace trees.