Rhizoctonia root rot of horseradish
Rhizoctonia solani
What you will see
On the cuttings (side roots) and on the main roots there are round to oval sunken dark brown spots 0.5–2 cm, with white fungal mycelium in damp conditions; they may be cracked or canker-like thickened. Yield loss up to 30%.
How to protect
- Prevention
- Keep to a crop rotation of at least three years; the fungus attacks many other crops.
- Cooler, quick-drying soils reduce infection.
- Side roots are the planting material for the next year, so the disease spreads through planting stock.
