Eriosoma lanigerum wingless females (apterae) are purple, red or brown and are the most often recorded form of this aphid.  They are usually found on their secondary host – Apple - causing lumpy irregular galls on branches, which become woody and persist after the aphids have left.  The aphid is a considered to be a pest of orchards and can cause damage to the tree.  

The aphids are covered in thick white flocculent (woolly) wax. This is produced by distinct wax glands on the head and along the thorax and abdomen. The body length of Eriosoma lanigerum apterae is 1.2 to 2.6 mm.

Gall Adult

Wherever the host plants occur.

Summer.

Wingless females of woolly apple aphids live in dense colonies on the roots, trunk or branches of the (secondary) host Apple (Malus) where it is a serious pest, often causing deformation and cancer-like swellings of bark which can be 1 cm across or much larger. Eriosoma lanigerum is also found on related species, such as Hawthorn (Crataegus) and Cotoneaster.

Status in Britain is difficult to determine due to lack of records but it is believed to be fairly frequent.

Status in Leicestershire and Rutland not known.

https://influentialpoints.com/Gallery/Eriosoma_lanigerum_Woolly_apple_aphid.htm