The aphid Pemphigus populi causes a green or greenish-yellow club-shaped gall to form on the leaves of Black Poplar and its hybrids such as Lombardy Poplar. The gall is found close to the base of the leaf. Mature Pemphigus populi alatae are greyish green with abundant wax. For extra information follow the ‘Further info:’ link below.

Gall Adult

If recording the gall, please provide photographs and state the host plant. If aphids are present within the gall, please also include images to show them. The position of the gall on the leaf is important when recording this species.

Galls may be noted where the host trees are found. 

Galls may be found when the host trees are in leaf.

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

Rarely recorded in Leicestershire and Rutland.

https://influentialpoints.com/Gallery/Pemphigus_populi_club-shaped_poplar-gall_aphid.htm