See:
Radish (Raphanus sativus) - White Rust
Cause The fungus-like organism Albugo candida has been found in a commercial operation in Oregon and in gardens in Washington and Oregon. Dew, fog, or periods of extended rainfall and cool temperatures favor disease development. Other hosts include canola, horseradish, and radish
Symptoms White to cream colored, blister-like lesions on leaves and siliques. Infected production plants were stunted and had overall poor growth.
Cultural control
- Select fields away from established radish fields.
- Control wild mustards around the field.
- Incorporate plant debris into soil soon after harvest.
Reference Glawe, D.A., Glass, J.R. and Putnam, M.L. 2004. First report of white rust of Lunaria annua caused by Albugo candida in North America. Online. Plant Health Progress doi:10.1094/PHP-2004-0317-01-HN.