Symptoms of (pink) snow mould disease in cereals

Under persistent snow cover, this pathogen can cause serious infections. Mainly a disease of winter barley, this page provides life cycle and symptom information.

• Snow mould – Monographella nivalis (Microdochium nivale) – is mainly a disease of winter barley, although other winter cereals are also occasionally affected
• Spring-sown crops are rarely affected
• Although it is commonly recorded, damage is rarely severe, except in isolated cases – especially where snow cover is more common and prolonged

When snow cover makes leaves touch the soil surface, infection occurs from hyphae growing from perithecia or from plant debris. Infection may also occur via the stem base or infected seed.

Typically, symptoms appear after snow melts in the spring.

Infected plants often have an extensive covering of white mycelium, which spreads on overlapping leaves and causes a matting of leaf tissue.

Later, as spores are produced on the mycelial mats, the affected patches assume a pink colouration (the disease is sometimes called pink snow mould).

It can cause patches of dead plants.

If large areas are affected, the crop may need to be redrilled (e.g. with spring barley).

However, most plants recover – especially in good growing conditions.

Affected plants or dead plant material carrying perithecia or mycelial growth are returned to the soil after harvest.