Worldwide distribution. On members of the cabbage (brassica) family, e.g., broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, radish. An important disease.
Bacteria enter natural openings at the leaf edge, and travel along veins, causing V-shaped rots, yellowing and death. Head rots develop, too.
Spread in rain, in seedlings, soil on machinery, shoes and in seed. Survives in debris and weeds.
Cultural control: certified seed or hot water (50°C for 25 mins); nursery hygiene: clean trays, pasteurise soil or use soilless mixes; monitor, and discard infected plants; well-drained fields, if necessary use raised beds; space plants for air circulation; weed; collect and burn debris or plough in remains after harvest; 3-4-year crop rotations.