Brown rot

Ralstonia solanacearum

Symptoms

• Sudden wilting of the leaves; leaves eventually turning brown
• No yellowing, necrosis or chlorosis of the leaf
• Wilted leaves hang along the stem
• Sometimes just one single stem but eventually the whole plant dies
• Bacterial slime from vascular bundles
• Sometimes only latent contamination (no symptoms)

Infection and spread

• Via seed tubers and volunteer potato plants
• Notifiable disease
• Can survive in the soil
• Can also be spread by irrigation water
• Alternative hosts include other Solanaceae eg. nightshades, tomato etc
• Bacteria rapidly spread to all parts of the plant
• Bacterial slime from roots, eyes and via soil

Possible confusion with

• Ring rot (Clavibacter michiganensis)