| Brown rot: Ralstonia solanacearum |
Symptom:
- Bangle blight or bangili
- Leaf- turns bronze colour, shrivel and die
- Vascular system of stem, root, stolon and tuber turns brown
- Ring disease - brown ring in the tuber due to discolouration of vascular bundles
- Whitish bacterial exudate oozes from the vascular system of cut stems and cut tubers
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Vascular ring |
Oozing out of bacterial exudates |
Rotting of vascular tissue |
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Identification of pathogen:
- Gram –ve, rod shaped bacteria, polar flagellum
- Forms no spores and capsules
Mode of spread and survival:
- Infected soil and seed tubers - source of infection
- Decay plant parts release masses of bacteria in the soil - viable from season to season
- Infection through wounds in roots which spread through vascular system into the stem
Epidemiology:
- Soil temp - 25 to 35°C
- RH - 50%
- Optimum pH - 6.2 to 6.6
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Management:
- Crop rotation - potato-wheat
- High degree of resistance - clones of Solanum phureja
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Source of Images:
http://fera.co.uk/plantClinic/documents/factsheets/brownrot.pdf
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