Acalitus ferrugineum is a species of eriophyid mite.

[1] This microscopic organism induces erineum galls on the leaves of American beech, and is known from the United States and Canada.

[2] Leaves affected by this species of mite will present with pale or light yellow erineum patches which progress into a reddish-brown later in the season.

These galls are not known to have any consequences on the health of the tree beyond aesthetics.

This article about a mite or tick is a stub.