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Bean rust
Uromyces appendiculatus
Fungal diseaseMedium impact
A common fungal disease of beans producing distinctive orange-brown pustules on leaves and pods. Most problematic later in the season and in humid conditions. Can reduce yield and plant vigour if established early.
Currently in peak season - extra vigilance worthwhile.
Key facts
- Type
- Fungal disease
- Affects
- Bean
- Active season
- Jun - Sep
- Peak season
- Jul - Sep
- Vulnerable stages
- Growing · Harvesting
- Spread rate
- moderate
- If confirmed
- Act soon
Signs & symptoms
- -small orange or rust-brown powdery pustules on the underside of leaves
- -corresponding pale or yellow spots on the upper leaf surface
- -leaves yellowing and dropping prematurely in severe cases
- -pustules occasionally appearing on pods
Management
Do now
- -Remove and bin badly affected leaves - do not compost
- -Improve airflow around plants by removing crowded growth
- -Avoid overhead watering which spreads spores
Prevention
- -Rotate bean crops to reduce soil-borne inoculum
- -Space plants at recommended distances to allow airflow
- -Clear crop debris promptly at the end of the season
Further reading
- -Bean rust spores are released from pustules and spread rapidly by wind and rain splash to neighbouring plants
- -The disease is rarely fatal to established plants but can significantly reduce late-season yields
- -Infection is most damaging when it establishes early in the season before the plant is cropping well