Woolly Aphid

Found on various host plants, especially on underside of leaves, twigs, and bark of trees like alder, beech, apple, and elm

Herbivorous; they feed on plant sap using piercing-sucking mouthparts

They produce a white, waxy, cotton-like substance for protection and often move together in colonies; some species alternate between two different host plant types

They are generally harmless to humans but can be a nuisance pest in gardens and agriculture by causing leaf curling, gall formation, and secreting sticky honeydew