GreenlyPotato blackleg: how to recognise and treat it
Disease
Symptoms
- Early in the season, some stems are stunted and pale green or yellow, with yellow leaves.
- Leaves at the top of affected stems stay small and stiff, with their edges rolled inwards.
- At ground level the affected stems are black and rotted.
- Tubers rot — the flesh turns grey or brown and soft, with the decay spreading from the stolon end.
Organic treatment
- Pull out and destroy affected plants as soon as you see symptoms, before the disease spreads through the soil.
- Lift tubers in dry weather and store them dry; discard any rotting tubers.
- Improve drainage on wet sites — the disease thrives in warm, damp conditions.
Chemical treatment
- There are no chemical controls available to gardeners for blackleg; rely on clean seed and removal of sick plants.
Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.
Prevention
- Plant commercially produced seed potatoes; if you save your own seed, take it only from healthy plants.
- Grow potatoes in a different place each year and dig out self-sown potatoes, where the bacteria survive.
- Choose resistant cultivars such as 'Charlotte', 'Pixie', 'Saxon' or 'Vales Sovereign'.
Plants it affects
Sources
Figures checked against these sources.