Hemlock Woolly Adelgids, (Adelges tsugae), on the branch of an Eastern Hemlock, (Tsuga canadensis), in the temperate forest of the Appalachian Mountains, southern North Carolina, USA. This aphid-like insect kills hemlocks by feeding on the sap at the base of the needles. Each tiny insect wraps itself in a white fuzzy covering which measures only 1mm across. Native to Asia, hemlock woolly adelgids have spread widely over the Appalachian Mountains in the eastern United States.