About Aceria ilicis (Canestrini, 1890)
Aceria ilicis is a gall mite in the family Eriophyoidea that causes felt-like galls called erinea, which form as patches of glandular hairs on holm oak (evergreen oak) leaves. These galls most often produce a 2–3 mm high bulge on the upper surface of a leaf, with a several-mm-wide depression on the lower leaf surface. Several galls typically appear on a single leaf, and the mites live inside the dense mass of tangled hairs that make up the gall. Occasionally, the bulge forms on the lower leaf surface instead, with the corresponding depression on the upper surface. This species is distributed across multiple European countries: Belgium, Croatia, France, Germany, Greece, Italy, the Netherlands, Portugal, Slovenia, Spain, Switzerland, and England (United Kingdom). It is also found in Turkey, which is in Asia.
