Saskatoon
Guides
Eriosoma americanum
Woolly Elm Aphid
Eriosoma americanum, commonly known as the woolly elm aphid, is a North American aphid species that alternates between two host plants: American elm (Ulmus americana) and Saskatoon (Amelanchier alnifolia). The species produces distinctive woolly or cottony wax secretions that give it its common name. Heavy infestations on American elm cause leaf curling and produce visible dark patches and cottony masses. Like other aphids, it excretes honeydew while feeding on plant sap.