Common birch aphid (Calaphis betulaecolens)
European birch aphid (Euceraphis betulae)
Pest description and damage The common birch aphid is a large green aphid and the European birch aphid is a large green and black species dusted with a powdery wax. They both feed on the undersides of leaves and produce copious amounts of honeydew. Sometimes birch begins to lose its leaves by late summer; excessive aphid feeding may compromise the vigor of the host. Aphid honeydew is a sweet, sticky secretion that collects on underlying plant tissues and encourages growth of a black sooty mold. In addition to cosmetics, honeydew may become a sticky nuisance when it falls on decks, cars, or other landscape surfaces.
For biology, life history, monitoring and management
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Insure that the plant receives enough water through the season. Place birch away from driveways, patios and decks to minimize the nuisance of honeydew.
Check the tree trunk for ladybeetle adults, eggs, larvae and pupae. Also, check for swollen tan or gray aphids stuck to leaves as they are a sign of parasitoids.
See Table 1 in: