The Hyalopterus pruni aptera is a small to medium sized aphid, with an elongate shape. It is usually pale green with a fine darker green mottling, covered with wax meal, but on the summer host (reeds) there are dusky red as well as green forms.

Aphid records cannot always be confirmed from images.

Associated with Prunus species (all year) and reeds (especially Common Reed (Phragmites australis) in the summer.

April to September.

The eggs of Hyalopterus pruni overwinter on Prunus species. They hatch in April. The population of Hyalopterus on plum continues to increase through June and July, and many aphids may remain on plum all year rather than migrating to the secondary host. Others move to the summer host (reeds) and on this host the species exhibits colour polymorphism, with two colour forms - green and dark red.

True status in Britain is difficult to determine to lack of records.

Status in Leicestershire and Rutland not known.

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