E. betulae is mainly green in colour but the body of the adult aphids is dusted with a pale bluish wax, which may also form a furry coating on the antennae and legs. A very similar species, Euceraphis punctipennis, is found on Downy Birch and detailed examination is needed to separate them.

Euceraphis punctipennis

On Silver Birch (Betula pendula).

Spring to autumn.

This species produces several generations of young each year. In summer all the adults are winged females that are produced without mating - parthenogenesis. They are very active and fly when disturbed. In autumn, when winged males and wingless egg-laying females are produced, sexual reproduction occurs and eggs are laid which survive over winter. In warm dry spells the aphids can build up large populations on the trees' leaves and rain droplets of sticky honeydew down onto anything or anyone underneath.

Common and widespread in Britain.

Common in Leicestershire and Rutland

https://influentialpoints.com/Gallery/Euceraphis_betulae_Silver_birch_aphid.htm