Woolly aphids are typically found in large numbers feeding on the branches of trees. In addition, some species of woolly aphids develop initially on roots (e.g. woolly apple aphid, Eriosoma lanigerum) and then later on migrate upward from the soil to feed on plant stems and branches. Woolly aphids feed on plant fluids within the phloem sieve tubes. They withdraw large quantities of plant fluids resulting in the production of honeydew, a clear sticky liquid that serves as a substrate for black sooty mold.
Young woolly aphids are all females (stem mothers) and can reproduce asexually (without mating). Winged and non-winged forms may be present simultaneously. The cornicles or tubes that protrude from the end of the abdomen may be substantially reduced compared to other aphid species.
Woolly aphids feed on mature maple trees and are not likely to cause significant plant damage. However, one of the easiest and quickest ways to remove woolly aphids from maple trees is to dislodge them using a forceful water spray. If done whenever woolly aphids are present, a forceful water spray will prevent populations from building-up. Although there are predators that will feed on woolly aphids including green lacewings, ladybird beetles, and syrphid fly larvae, in most cases, the predators do not provide sufficient regulation of woolly aphid populations. (Raymond Cloyd)