''Rabdophaga nervorum'' is a gall midge which forms

gall 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 ...

s on the leaves of

sallows Sallows is a fell in the English Lake District, rising between the valleys of Kentmere and Troutbeck. It is the highest point in the upland area to the south of Garburn Pass, variously termed Kentmere Park and Applethwaite Common on Ordnance S ...

(''Salix'' species). It is found in Europe and was first described by the French

entomologist Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arach ...

, Jean-Jacques Kieffer in 1895.

Description

The genus ''Salix'' supports many galls, some of which are difficult to identify, particularly those caused by the gall midges in the genus ''Rabdophaga''. ''Rabdophaga nervorum'' forms galls on the midrib of leaves on sallows. The gall, is an approximately 2–3 mm, spindle-shaped swelling on the underside of the midrib of a leaf. The swelling is not hard and contains a single, pale yellow larva. Pupation occurs within the gall. The gall has been found on white willow ( ''S. alba''), ''S. appendiculata'', eared willow ( ''S. aurita''), Babylon willow ( ''S. babylonica''), goat willow ( ''S. caprea''), grey willow ( ''S. cinerea''), olive willow ( ''S. elaeagnos''), crack willow ( ''S. fragilis''), black willow ( ''S. nigra''), bay willow ( ''S. pentandra''), tea-leaved willow ( ''S. phylicifolia'') and purple willow ( ''S. purpurea'').

Distribution

''Rabdophaga nervorum'' has been found in Finland, France, Germany and Great Britain (England, Scotland and Wales).

References

nervorum Nematoceran flies of Europe Gall-inducing insects Insects described in 1895 Taxa named by Jean-Jacques Kieffer Willow galls {{Bibionomorpha-stub