Cavity Spot
Pythium violae and Pythium sulcatum
Pathogen
Fungus
Hosts
Carrots
Symptoms
Small sunken lesions on the root surface. Usually less than 1.3 cm in diameter and extending in a horizontal direction. These lesions, usually associated with the top third of the tap root, can be further invaded by other saprophytic bacterial and fungal pathogens.
Development
Soil borne Pythium disease which can penetrate early in the crop growing season and enlarge as the roots develop.
Favourable factors
Heavy rainfall and cool, wet growing conditions.
Importance
All varieties are susceptible and also a disease of parsnips.
More visible after washing and can severely affect crop quality rendering produce unmarketable for processing or the fresh market.
Control
Raised beds
Reduced irrigation
Long rotation
Start protective fungicide programme in furrow at drilling
Grow on light soils
Harvest early
