The youngest leaves start to wilt during the hottest part of the day and partly recover when temperatures are cooler. Under favorable conditions, the wilting may affect the whole plant and stay permanent. The wilted leaves maintain their green color and remain attached to the stem. The roots and lower part of the stem show a dark brown discoloration. The invaded roots may rot due to infection from secondary bacteria. When cut, stems can leak a white to yellowish, milky secretion.
Cause
The bacterium can live long in soils, it can survive in plant debris or on alternative hosts. It enters the plant through wounds in the root system during the emergence of lateral roots. Elevated temperatures (from 30°C to 35°C), high humidity and soil moisture, and alkaline soil pH favor disease development. Heavy soils that can retain soil moisture for long periods are particularly vulnerable. Main alternative hosts for Ralstonia solanacearum include tomato, tobacco, plantain and banana.
Hosts
Prevention
- Plant resilient varieties.
- Ensure pathogen-free soil, irrigation water, seeds, and transplants.
- Provide good drainage to the field.
- Crop rotation for periods of 5 years or more.
- Ensure a slightly acidic soil-pH of 6,0-6,5.
- Ensure a good nutrient supply.
- Remove infected plants to avoid spreading.
- Avoid transferring equipment from contaminated to uncontaminated soils.
- Disinfect tools with bleach before working on the next field.
- Destroy all infected plants as well as residues by burning.
Treatment
| Control Dose/Litre | Trade Names |
| 2-3 gram | Bactrinashak, Streptocycline, Plantomycin |