The tree-killing emerald ash borer has now spread to every county in Wisconsin, state officials said on July 26.
The state Department of Natural Resources said agency staff responded to a report of a possible emerald ash borer infestation in two trees at a private residence in the town of Meenon in Burnett County on June 13.
Tests the U.S. Department of Agriculture Animal and Plant Health Inspection Service conducted on insect samples taken from the trees confirmed the specimens were emerald ash borer.
Native to Asia, the emerald ash borer was discovered in the United States in southeastern Michigan in 2002. Officials believe the beetle has been moving around the country by hitching rides on firewood.
By 2008, the invasive pest had made its presence known in Wisconsin, detected in the southeastern part of the state.
The lifecycle of the emerald ash borer is simple yet devastatingly effective. Adult beetles lay eggs on the bark of ash trees. Upon hatching, larvae burrow into the tree, feeding on the inner bark and disrupting the tree’s ability to transport water and nutrients. The process effectively girdles the tree, leading to its inevitable death within three to five years of infestation.
The economic impact has also been significant, with municipalities and homeowners facing substantial costs for tree removal and replacement, as well as for implementing preventative measures.
Quarantines and regulations were initially established to restrict the movement of ash wood and firewood from infested areas, attempting to curb the spread to uninfested regions. Despite these efforts, the outlook for Wisconsin’s ash trees remains grim.
According to the USDA’s Animal and Plant Health Inspection Service, it is currently present in 36 states and the District of Columbia. It was first discovered in Wisconsin in 2008 in Ozaukee County.
Emerald ash borer larvae bore into ash trees, killing them. The DNR expects that the beetle will eventually kill more than 99% of Wisconsin’s white, black and green ash trees.
