Plantwise Factsheets for Farmers
Management of Damping off Disease in Tomato
Rhizoctonia spp., Phytophthora, Pythium
Recognize the problem
Damping off is a major disease of young tomato seedlings and losses can reach 80 - 100%. The disease can be caused by several different pathogens (Pythium, Phytophthora and Rhizoctonia species) but the same symptoms occur. The seedlings either fail to emerge from the soil or fall over and die immediately after emergence.
These fungal pathogens can survive for several seasons in wet soil. Poor drainage, compacted soil and inadequate air flow increases the chances of this seedling disease. Infection spreads through the soil and is generally worse when temperatures are cool and the weather is wet.
- Select a well-drained site for your nursery and do not over water
- If the disease affects seedlings in the nursery, consider relocating the nursery to another site before replanting
- Use certified disease-free seeds
- The heat from sunlight or burnt straw can be used to kill the fungus prior to planting
- Follow the recommended sowing densities, do not plant seeds too close together
- Plant spacing is 10cm between rows at the nursery stage
- Proper spacing for transplanting in the field is 60 x 70cm
- The soil can be treated with fungicides before transplanting such as metalaxyl (Ridomil WP) 3kg/ha or copper oxychloride 2kg/ha to prevent the disease in the field
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.
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