Snow rot (grey or speckled snow mould) disease in wheat and barley

Snow rot infection rarely leads to serious levels of damage and yield loss. Find out which cereals and cropping situations favour disease infection and development.

• Snow rot is commonly recorded but damage is rarely severe
• The disease is generally more damaging where snow cover is more common and prolonged
• It is of higher risk in continuous winter barley stressed with manganese deficiency
• The disease also affects winter wheat
• Spring-sown crops are rarely affected

Note: This disease is also known as grey or speckled snow mould.

The pathogen (Typhula incarnate) overwinters as sclerotia in soil and on crop debris.

The sclerotia germinate and produce spores and/or mycelia, which infect emerging winter-sown crops – often under snow cover.

The fungus infects the oldest leaves first.

Plants affected by snow rot usually have abundant red-brown resting structures (sclerotia), which are 2–3 mm in diameter, embedded in the lower leaf sheaths and on dead leaf tissue.

Eventually, the whole plant can turn yellow and start to wilt.

However, good growing conditions often allow crop recovery.

Surviving tillers compensate for dead shoots, so yield loss is usually small.

In extreme situations, plants can die.

Where large areas of crop die, redrilling with spring barley may be necessary.

Resting structures (sclerotia) of snow rot on lower leaf sheaths