Unsightly galls form where aphid colonies have attacked. These can split, letting in diseases such as apple canker. Woolly aphids don’t attack the roots, but they can infest the base of the trunk.

They feed by sucking sap through fine tubular mouthparts, which they insert into the plants' cells. Greenfly are part of the larger group known as aphids, which also includes blackfly, root aphids and ...

The pests cause many issues for the hosts as they feed on sap, and the signs of damage show on branches and roots. Woolly ...