Pests & diseases › Halo Blight
Halo Blight
Bacterial disease of French and runner beans. Small angular brown spots ringed by a pale yellow halo.
Symptoms
- Small dark spots with bright yellow halos on leaves
- Greasy patches on pods
- Stunted growth, yellowed seedlings
- Seed-borne — affected plants often come up sick
Lifecycle
Bacterium overwinters on infected seed and crop debris. Spreads in rain splash during cool wet weather.
What to do
- Remove and bin (don't compost) affected plants
- Avoid working among wet plants — bacteria spread on tools and hands
- No effective spray once established
If it's bad
- No chemical control available to UK gardeners
Stop it coming back
- Buy certified disease-free seed
- Don't save seed from infected plants
- Rotate beans on a four-year cycle
- Wide spacing, good airflow
Crops it goes for
Plan the plot, track every sowing, cook the harvest
Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.