Woolly apple aphid—Eriosoma lanigerum
Adult woolly apple aphids have reddish to purple bodies and are completely covered with woolly white
wax. Unlike other aphids, they primarily infest woody parts of trees.
Identification of species | Life cycle
Woolly apple aphids infest roots, trunks, limbs, and shoots, producing galls at the site of infestation.
Root colonies cause swollen, nodular masses of gall tissue to form, stunting the tree. Aerial colonies
are found in growth cracks, wounds, or at the axils of leaves on first- and second-year wood. Cankers
and burs can develop on tree limbs.
The parasite Aphelinus mali, with the help of other
natural enemies, can completely control aerial colonies.
Sprays of insecticidal
soaps or horticultural
oils may control light populations on limbs. Root-infesting
populations cannot be controlled with pesticides. Where woolly apple aphid is a serious problem, consider
resistant rootstocks, such as M111 or M106.
For more information, see the Aphids
apple aphid adults
on limbs caused by woolly apple aphids