Aculus craspedobius

Aculus craspedobius is a species of mite which causes galls on the leaves of willows ("Salix" species). It was first described by Alfred Nalepa in 1925.
Description.
According to Redfern et al. (2011), the gall of "A. craspedobius" is similar to the gall of "A. magnirostris" and the mites need to be examined for firm identification. The gall of "craspedobius" is a short, 1–2 mm narrow twisted, downward roll on the leaves of eared willow ("S. alba"), crack willow ("S. fragilis") and their hybrids in Great Britain. The gall is lined with red hairs and contains the mites. Elsewhere it has been found on goat willow ("S. caprea") and purple willow ("S. pururea").
In comparison, the galls of "A. magnirostris" differ by a longer downward roll on the leaf edge. On the website "Plant Parasites of Europe", photographs of "A. magnirostris" are similar to the description for "A. craspedobius".
Distribution.
"Aculus craspedobius" has been found in Austria, Germany, Great Britain and Poland.