Pacific Pests, Pathogens and Weeds

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Summary

• Worldwide distribution. On Vigna species, crops (cowpea, long bean) and weeds. Another species infects Phaseolus. Rust comes late, and the impact is relatively small.
• Reddish-brown, circular pustules with yellow halos on leaves and pods, producing powdery spores.
• Spread by spores blown 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.