Pemphigus populitransversus also known as poplar petiole gall aphid or cabbage root aphid, induces galls on the leaves of poplar trees.

They lack cornicles on the abdomen and have relatively short antennae and legs compared to other aphid species.

The female P. populitransversus then lays her eggs inside of it.

These galls are green or red, fleshy, smooth, and up to 14 mm in diameter.

A slit allows the aphids to exit the gall.