AUGUSTA, Maine (AP) — Officials in Maine have announced a formal quarantine to slow the spread of a beetle that has killed hundreds of millions of ash trees since its discovery in North America.

The emerald ash borer was first found stateside in Michigan in 2002 and has spread to dozens of states and four Canadian provinces. Loggers are cutting down large numbers of ash trees to try to stay ahead of the pest.

The Maine Department of Agriculture, Conservation and Forestry said Wednesday that the quarantine includes all of York County and the northeastern corner of Aroostook County.

The quarantine rules prohibit the movement of ash trees grown in nurseries from the quarantine area and regulate the movement of products such as untreated ash lumber.