ELKINS, W.Va. -- U.S. Forest Service scientists have identified 40 sites in the Monongahela National Forest as treatment areas for combating the spread of the hemlock woolly adelgid, a non-native insect that has been killing hemlock trees throughout the East for decades.

First reported in the United States near Richmond, Va., in 1951, the tiny pest had established itself in 16 states from Georgia to Maine by 2005. It was first detected in West Virginia in 1992, and has now spread throughout the range of the hemlock within the 920,000-acre Monongahela National Forest.

Scientists believe the insect could infest the entire range of the eastern hemlock within 30 years. After a stand becomes heavily infested, trees can start dying within five to six years, and more than 90 percent are dead in 10 to 12 years.

Current treatment procedures for protecting hemlocks from the pest are so costly and labor intensive that it is impractical to launch a forest-wide treatment scheme. As an alternative, a plan is being developed to limit treatment to zones containing rare, hemlock-dependent species, brook trout streams that depend on hemlock shade, dispersed recreation areas, old-growth hemlock stands and scenic areas.

Developed recreation areas in the Monongahela with hemlock stands have been treated to guard against the spread of hemlock woolly adelgid since 2005.

The planned effort to check the spread of the insect in 40 treatment zones would involve insecticide injections into the soil around the trees, or directly into the trees to save genetically viable hemlocks over the short term. A second treatment phase would involve the release of adelgid-specific predator beetles to help control the pest.

The Forest Service is encouraging the public to identify treatment areas in addition to the 40 zones already being considered. A list of the 40 zones identified so far is available by writing to David Ede, forest planner, at 200 Sycamore St., Elkins, WV 26241, sending email to ...@fs.fed.us, or calling Ede at 304-636-1800, extension 233.