''Aceria campestricola'', is a species of

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...

in the family Eriophyidae. The mite causes

galls Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

on the leaves of elms (''

Ulmus Elms are deciduous and semi-deciduous trees comprising the flowering plant genus ''Ulmus'' in the plant family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of Nor ...

'' species) and was described by

Georg Ritter von Frauenfeld Georg Ritter von Frauenfeld (3 June 1807, Vienna – 8 October 1873) was an Austrian naturalist and one of the leading scientists on board the Austrian frigate ''Novara'' during its round-the-world voyage. He was heavily involved in the develo ...

in 1865.

Description

The mites pass the winter hidden in bark crevices and in the spring attack the leaves. The gall is a small pimple or pouch, 1–2 mm across, on the blade or the veins. They are rounded above and have a hairy opening below, with or without a conical projection. Galls are greenish-yellow and redden when exposed to sun, they can be numerous and contain mites. There is some disagreement as to which species is involved in forming the galls. Mite pimples on elms with small leaves, vary in size and some of the large galls have stalked dimples The small galls have been described as '' Aceria ulmicola'' (Napela) and the stalked galls as '' Aceria brevipunctata''. Galls have been found on the leaves of the following trees; wych elm (''

Ulmus glabra ''Ulmus glabra'' Hudson, the wych elm or Scots elm, has the widest range of the European elm species, from Ireland eastwards to the Urals, and from the Arctic Circle south to the mountains of the Peloponnese and Sicily, where the species reaches i ...

''), Dutch elm ''Ulmus'' x ''hollandica'', European white elm ('' Ulmus laevis''), field elm (''

Ulmus minor ''Ulmus minor'' Mill., the field elm, is by far the most polymorphic of the European species, although its taxonomy remains a matter of contention. Its natural range is predominantly south European, extending to Asia Minor and Iran; its northern ...

'').

Distribution

Found in most of Europe and North America.

References

{{Taxonbar, from=Q50363714 Eriophyidae Animals described in 1865 Arachnids of Africa Arachnids of Europe Galls Taxa named by Georg Ritter von Frauenfeld