Pathogen 

• Urocystis occulta

Hosts

The disease is specific to rye.

Symptoms

This disease differs from the other smuts of UK cereals in that it affects not only the ears but also the stems and leaves. It is specific to rye, producing long dark blisters in stripes parallel to the veins which eventually rupture to expose the spores.

Life cycle

The disease is both soil-borne and seed-borne. The developing grains in ears are contaminated by windblown spores but the spores remain on the seed surface. Infection of the seed occurs at germination as with bunt. Soil-borne inoculum is more important with this disease than with the smuts affecting other cereals in the UK.

Importance

The disease is sporadic in occurrence but rarely causes significant loss.