GreenlyChocolate spot: how to recognise and treat it
Disease
Symptoms
- Small round red-brown spots on leaves, stems, flowers and pods; they later get a grey dead centre with a red-brown margin.
- In wet weather the spots spread aggressively, turn darker brown and merge, and the leaves shrivel; in dry weather they stay small.
- Severe attacks cause flowers and leaves to drop, and infected stems may collapse.
Organic treatment
- At the end of the season destroy infected plants and all debris; there is no curative spray for gardeners, so control relies on growing conditions and hygiene.
Chemical treatment
- No fungicides are available to home gardeners for chocolate spot; fungicide sprays at flowering are used only on farm crops.
Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.
Prevention
- Space plants more widely to let air move between them, and avoid damp, humid, sheltered sites.
- Remove common vetch growing nearby — it carries the fungus over winter.
- Do not save seed from infected plants, and do not sow where broad beans grew recently.
- Choose cultivars with good resistance to chocolate spot where available.
Plants it affects
Sources
Figures checked against these sources.