The caterpillars have infested about one million acres of forest between Clearfield and Dauphin counties in central Pennsylvania, said Barry Towers, chief of forest pest management for the state Department of Conservation and National Resources. By comparison, the 1991-1992 outbreak claimed about four million acres statewide, Towers said. The caterpillars can kill trees by eating their leaves. But they pose other unique problems in populated areas, Towers said. They can invade homes, and soil sun decks and porches.
Some people develop rashes if they are around the caterpillars' hair.
Towers said that all depends on a fungus. It remains to be seen, Towers said, whether this year's wet spring will result in healthier fungi next year which will eat into the gypsy moth numbers. Herb Landis, a state forester who oversees eight western Pennsylvania counties and investigated Warman's claims, said the fungus killed most of the moths in his jurisdiction. The bugs are native to China but were brought to Massachusetts in 1863 by a French scientist who hoped to crossbreed them with silkworms, until they escaped from his laboratory. Slowly, the caterpillars infested New England states and the eastern seaboard, arriving in Pennsylvania in the early 1960s.