Bacterial Wilt
Ralstonia solanacearum
Soil-borne bacterium that rapidly wilts tomatoes, potatoes and capsicums in warm wet soils. No cure once plants show symptoms.
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Identify from a photoBackground
Ralstonia solanacearum is a soil and water-borne bacterium that invades roots and colonises the plant's water-conducting system. Infected plants wilt without yellowing, sometimes within a day in warm weather. A cut stem in a glass of water produces milky bacterial ooze within minutes, a quick diagnostic that distinguishes bacterial wilt from Fusarium.
How to identify
- Sudden wilt of whole plant, often without yellowing
- Cut a lower stem lengthwise. Vascular tissue brown, dark ooze
- Place cut stem in clear water. Milky white bacterial streams from the cut surface
- Affected plants collapse in days
Life cycle
Survives in soil, water and host plants for years. Enters through root wounds. Moves through vascular system. Released back into soil on plant death.
Weather triggers
- Temperature: 22-35°C
- Warm wet soils are critical. Much less active below 20C.
Peak season (southern hemisphere)
Red = active season · Dark red outlined = this month
Affected vegetables & crops
Click any crop to see current prices and growing info.
Climate zones at risk
Organic & low-impact control
- No treatment once plants are infected. Remove and destroy (do not compost)
- Long crop rotation away from solanaceous crops (5+ years) in infested soils
- Solarisation in peak summer
Chemical control
- No effective chemical treatment
Always read product labels. Registrations change.
Prevention
- Plant certified disease-free seed potato
- Avoid moving infested soil on tools and boots
- Rotate away from solanaceous crops for 4+ years
- Improve drainage
Companion planting
No specific companion effect.
Biosecurity
Different strains have different host ranges; some race 3 strains are regulated.
Know when Bacterial Wilt is actually about
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