First detected in Minnesota in May 2009, the emerald ash borer has spread throughout St. Paul and Minneapolis, as well as counties in southeastern Minnesota. As of mid-April, the Minnesota Department of Agriculture had logged nearly 1,300 infestation sites. Thanks to data provided by the MDA's chief bug hunter, Mark Abrahamson, my colleague Alejandra Matos pulled together this map to show the pest's mounting toll on our forests.