poplar leaf-base gall

Poplar leaf-base gall is a plant parasitic, gall making aphid. Like similar aphids, it is most often identified by the plant species on which the gall is found, by the location of the gall, and by the gall’s appearance.

In Minnesota this species is found on balsam poplar, Lombardy poplar, and plains cottonwood. A gall is formed by the tree in response to an aphid feeding on the petiole. The gall appears at the junction of the leaf stalk (petiole) and the leaf blade. It is light green, smooth, spherical, and ¼″ to ½″ in diameter. There is a slit-like opening in the gall parallel to the direction of the petiole.

The adult female is ⅛″ long from the head to the wing tips. The antennae are thick and stout. The wings are transparent and colorless.

Total length: ⅛″

Poplar petiolegall aphid (Pemphigus populitransversus) forms a gall near the middle of a leaf petiole. The opening in the gall is a slanted, sideways (transverse) slit.

Breeding takes place within the gall. Adults escape the gall through the slit-like opening.

balsam poplar (Populus balsamifera)

Lombardy poplar (Populus nigra)

plains cottonwood (Populus deltoides ssp. molinifera)

Sources

7, 24, 29, 30, 82, 83.

Common and widespread; wherever its host species occur.