The Emerald Ash Borer (EAB) is an invasive insect that has been decimating ash trees throughout the Great Lakes states. It was first discovered in Minnesota in 2009 and is now found in four counties (Hennepin, Houston, Ramsey, and Winona). EAB poses a particularly serious threat to Minnesota because it is home to nearly 1 billion ash trees that occur throughout the state - the second most of any state.
Native to the western United States and Canada, mountain pine beetle is considered the most devastating forest insect in North America. Trees usually die as a result of infestation and an unprecedented outbreak in the west is currently decimating pine forests there. While mountain pine beetle is not presently believed to reside in Minnesota, there are risks posed by an expanding species range resulting from warming climate and the potential for accidental introduction via lumber imports from infested areas.