Botrytis

Botrytis cinerea

Symptoms

• Lesions often at the edge or point of the leaf
• Alternating light grey and dark bands within infected tissue
• The edge of the lesion is often light green to yellow
• Infected tissue shrinks
• Grey mycelium on both sides of the leaf
• Stem infection is possible after haulm destruction
• Stems become hollow and papery white
• Elongated sclerotia (not bigger than 2mm) firmly attached to the stem
• Seldom infects tubers

Infection and spread

• Is generally found on dying and dead tissue
• Spores are always present
• Often occurs in combination with sulphur deficiency

Possible confusion with

• Late blight (Phytophthora infestans)
• White mould (Sclerotinia sclerotiorum)