- Worldwide distribution. On Phaseolus species. Usually, a major disease depending on variety.
- Circular pustules, 1-2 mm, light green at first on both leaf surfaces, with halos on the top. Bursting to produce reddish-brown spores.
- Spread is by spores in the wind.
- Cultural control: plant beans with maize, at random, not in rows; use a 2-year crop rotation; do not plant overlapping crops; resistant varieties; collect and burn trash after harvest.
- Chemical control: use mancozeb, starting when the spots are first seen.