any plant louse of the family Aphididae, characterized by a waxy secretion that appears like a jumbled mass of fine, curly, white cottony or woolly threads, as Eriosoma lanigerum(woolly apple aphid or American blight) and Prociphilus tessellatus(woolly alder aphid).
any of various aphids that produce white waxy threads, as Adelges piceae(balsam woolly aphid).
