Willowherb Rust - Puccinia pulverulenta

The rust causes galls on the leaves of Willowherbs (Epilobium) and the whole plant appears paler than usual, with curled leaves.  There is no host alternation.  Raised yellowish blotches bear orange aecia, usually on underside of leaf; brown uredinia and telia are present later.  

Where willowherbs are plentiful.

Summer

The fungus releases orange spores from the pustules and these are spread by the wind to initiate new infections on leaves.

Widespread and fairly frequent in Britain.

Thought to be fairly frequent in Leicestershire and Rutland.