Gardeners the world over dread the appearance of aphids on their plants. There are around 4,000 species of these sap-sucking insects and about 250 are pests that can wreak havoc on crops in a garden or orchard.
One of them is the woolly apple aphid (Eriosoma lanigerum). As its name suggests, this aphid attacks apple trees and is recognisable by the white, waxy excretions that cover and protect the insects.
