''Rabdophaga degeerii'' is a

gall midge Cecidomyiidae is a family of diptera, flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small in ...

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. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...

s on the shoots of

willow Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...

s (''Salix'' sp).

Description

The gall can be a smooth, globular or a spindle-shaped swelling on a shoot. The gall chamber is in the pith and contains pale orange larvae or pupae in separate chambers. Correct identification of the host species is important, as the gall of ''R. degeerii'' is similar to ''R. salicis''. In Britain the gall on purple willow (''Salix purpurea'') is recorded as ''R. degeerii''. Elsewhere the gall has been found on ''S. daphnoides'' and ''S. elaeagnos''.

Distribution

The insect or gall has been found in Denmark, France and Great Britain.

References

degeerii Nematoceran flies of Europe Gall-inducing insects Insects described in 1847 Taxa named by Johann Jacob Bremi-Wolf Willow galls {{Bibionomorpha-stub