• Lesions - brown, slightly depressed and circular with fimbriate margins
• Dotted with minute black specks or sclerotia of the pathogen
• Organism invades only the cork cells which are destroyed and slough off forming a ‘scurf’

Identification of pathogen:

• Hyphae – septate, branched, hyaline and become brown with age
• Conidia- dark brown, club shaped, thick walled
• Hyphae form minute sclerotia
• Pathogen live from season to season on the affected tubers and in the soil
• Spread from diseased to healthy tubers in storage

• Use of disease free seed material
• Seed treatment- mercuric chloride - 0.1% for 30 min