The gypsy moth is one of the major insect pests of hardwood trees in the East. The gypsy moth is not native to this country and was introduced into the United States in 1869 by a French scientist living in Massachusetts. The first major outbreak occurred in 1889 and since that time, gypsy moth populations have moved steadily from New England toward the southwest.

Gypsy moth caterpillars cause damage to the forest by defoliating and stressing trees. This provides an opportunity for secondary organisms to weaken the trees further and to cause mortality. When gypsy moth populations are dense, the caterpillars will feed continuously until the tree is completely stripped. Gypsy moths prefer hardwoods, but may feed on several hundred different species of trees and shrubs. In our region, the preferred food of the gypsy moth is oak.

The first reported defoliation by gypsy moths in West Virginia was in 1985 when slightly over 3,000 acres were defoliated in the Eastern Panhandle. The gypsy moth subsequently spread down the ridges into Pendleton, Pocahontas, and Greenbrier counties, crossed the higher mountains of Preston, Tucker, and Randolph counties, and spread southwest into Ritchie, Gilmer, Braxton, and Webster. As of 2003, over two million acres of hardwood forest in West Virginia had been defoliated. In 2008, the West Virginia Department of Agriculture imposed a quarantine in 33 counties to restrict further infestion by the gypsy moth. Despite its efforts, the WVDA reported that 44,000 acres had been defoliated in 2009. In 2010, plans were announced to spray 62,600 acres of timberland in southeastern West Virginia to slow the spread of the gypsy moth.

The state Division of Forestry still considers the gypsy moth to be the most potentially destructive forest pest in West Virginia. The greatest concentrations are in Jefferson, Berkeley, Morgan, Hampshire, Hardy, Pendleton, Grant, Mineral, Tucker, Randolph, Pocahontas, Preston, Taylor, Barbour, Monongalia, Marion, Hancock, Brooke, Ohio, Marshall, Wetzel, Harrison, and Upshur counties.