Aceria

Aceria is a genus of mites belonging to the family Eriophyidae, the gall mites. These tiny animals are parasites of plants. Several species can cause blistering and galls, including erineum galls. A few are economically significant pests, while others are useful as agents of biological pest control of invasive plants such as rush skeletonweed (Chondrilla juncea), creeping thistle (Cirsium arvense), and field bindweed (Convolvulus arvensis). There are over 900 species in this genus.