woolly adelgid noun Etymology: adelgid ultimately from New Latin Adelges, probably irregular from Greek adēlos unseen Date: 1987 either of two aphids (genus Adelges ) with a white woolly coating that have been accidentally introduced into North America:, one ( A. piceae ) native to Europe that is a serious pest of fir trees, one ( A. tsugae ) native to Asia that is a serious pest of hemlocks
