Sclerotinia

Sclerotinia sclerotiorum

Symptoms

• Infection starts in the leaf axils, on damaged tissue and flower remnants on the leaves
• After long periods of rainfall typical cottony white mould forms on lower stem parts and leaf axils
• In the stem the mycelium contains typically large sclerotia up to 1cm in length
• Sclerotia are loose within the stem
• Foliage becomes yellow and wilts
• Stems become hollow, woody and papery white

Infection and spread

• Survives in soil as sclerotia
• From sclerotia grow small, orange apothecia on which develop sexual ascospores
• Spores are dispersed by wind and infect wind or rain damaged crops
• Alternative host plants: peas, beans, chicory and carrot

Possible confusion with

• Stem rot
• Grey mould (Botrytis cinerea)