Violet Smut - Urocystis violae

The smut fungus Urocystis violae induces elongate swellings on the petioles and leaf veins, and/or leaves of Viola. Affected parts are usually swollen and strongly distorted and may also be recorded as a gall. The swellings open to release a black spore mass, composed of many individual balls of spores.

Petiole swellings and Black spore mass.

Unless identified by a recognised expert, photos of the smut and the host plant is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

The smut may be seen wherever the host Viola species are found.  These are Viola odorata, also on V. riviniana, V. reichenbachiana and V. hirta (but not yet recorded on these last three hosts in VC55).

Spring

It seems to be nationally scarce: only 11 records in the NBN post-2000, 5 from England.

Rare in Leicestershire and Rutland. The 2023 record is the first for VC55.