Flat, often shield-like or strongly inflated aphids, often covered by white wool; needle/leaf-symptoms: spots; damage by sucking on shoots, twigs, stems: bark necroses, dieback, rarely death of the whole tree
Affected tree species
Alder; All tree species; Apple; Ash; Barberry; Beech; Birch; Bladdernut; Boxelder; Cedar; Cherry; Common grape wine; Common medlar; Common whitebeam; Cotoneaster; Dogwood; Douglas fir; Edible chestnut; Elder; Elm; English ivy; European Hornbeam; European mountain ash; Ex-Robinia; Forsythia ; Framire; Giant sequoia; Ginkgo; Hackberry; Hawthorne; Holly; Honeysuckle; Horse chestnut; Japanese Pagoda tree; Juniper; Juniper cultivars; Larch; Leyland cypress; Lilac; Linden, Lime; Magnolia; Maple; Mulberry; Myrtle, Creeping Myrtle; Oak; Olive tree; Pear; Plane; Poplar; Privet; Redwood; Rhododendron; Rose; Serviceberry; Southern Catalpa; Spruce; Thuja; Tree-of-heaven; Walnut; Wild service tree; Willow; Yew;
Leaf; Needle; Stem; Shoot/Twig/Branch;
Common on numerous plant species; effects are mostly loss of leaves or needles, which may weaken the plants, predisposing them to secondary damaging agents; some species may cause the death of plants by themselves.
Curative measures Only in case of epidemics and dependent on the aggressiveness of the species chemical control by insecticides (see official register of Plant Protection)
Scale insects on young maples: mass development within bark protecting columns