CHARLESTON, W.Va. -- A West Virginia program aimed at a pest killing the state's hemlock trees is expanding.

The pilot project combatting the invasive woolly adelgid is being expanded to Summers and Raleigh counties. Those two are in addition to Fayette and Nicholas counties that were included in the program last year.

Native to Asia, the beetle was discovered in Virginia in 1951. Since then, it has spread to suck up the sap of the stately evergreens in at least 16 Eastern states.

The West Virginia program helps private land owners combat the pest in private woodlots with treatments that protect the trees for four to five years.

The expansion was announced Wednesday by Commissioner of Agriculture Gus R. Douglass.