KITTERY – The Maine Transportation Department has removed more than 20 hemlock trees from an interstate rest area to control the spread of the hemlock wooly adelgid, an invasive insect that defoliates the trees and can kill them.

About eight large trees and 12 to 18 smaller ones were removed last week from the Interstate 95 rest stop, officials said.

The pest, first detected in Maine in 2003, is such a threat to the state’s forest economy that it is under a quarantine in some York County towns by the Maine Forest Service.

Some of the trees that were removed were within 30 feet of the highway, so forestry officials decided to take them down so the insects wouldn’t hitch rides on cars, trucks or birds to other parts of the state.

The adelgid sucks the sap from hemlocks, causing the trees to wither and eventually die.

Since the insect migrated from Asia to Virginia in the 1950s, wind and birds have spread its eggs as far north as Maine and across the Appalachian Mountains to Kentucky.