Common birch aphid (Calaphis betulaecolens)
European birch aphid (Euceraphis punctipennis)
Pest description and damage The common birch aphid is a large (0.12 to 0.14 inch in length) lemon-green aphid and the European birch aphid is a larger (0.12 to 0.2 inch long) pale green aphid with dark green to black bars on its back. 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
See "Aphid" in:
Ensure that the plant receives enough water through the season. Plant 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 the udersides of leaves as these are signs of aphid parasitoids.
See Table 1 in: