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Fusarium crown and root rot
Quick facts
- Fungus may result in stunted seedlings, rotting roots, stem discoloration, wilting and death.
- Hosts include tomato, pepper, eggplant, and a number of common weeds.
- The fungus can spread by root-to-root contact, the air, or surfaces such as equipment, other plants, and workers.
- There are some tomato varieties with resistance to Fusarium crown and root rot. Various cultural control methods are recommended.
Pathogen
The fungus Fusarium oxysporum f. sp. radicis-lycopersici (FORL)
Host range
Tomato, pepper, eggplant, and a number of common weeds. The complete host range is not known.
Identification
Signs and symptoms
- Stunted, yellowed seedlings.
Yellowing of tomato plant leaves due to Fusarium crown and root rot - Lower leaves turn yellow and drop prematurely.
- Plant wilts and may die.
Plant wilted from Fusarium crown and root rot. - Chocolate brown lesion girdles the main stem just above the soil line.
- Reddish to brown discoloration of the stem cortex when sliced lengthwise.
Lower stem infected with Fusarium crown and root rot - Rotted, discolored, and stunted roots.
Environment
- Cool temperatures (50 to 70°F optimum).
- Low soil pH.
- Areas of poor drainage, waterlogged soil.
Biology and disease cycle
- Spores produced on stem lesions can spread through the air and infect above ground plant parts.
- The fungus can spread by root-to-root contact, resulting in clusters of diseased plants.
- Spread through movement of soil and roots on equipment, plants, and workers.
- The fungus survives as thick walled spores (Chlamydospores) in soil, wooden stakes, and other high tunnel surfaces.
Management
Resistant varieties
There are some tomato varieties with resistance to FORL. In addition, susceptible varieties can be protected by grafting onto resistant varieties.
Cultural control
- Maintain a soil pH of 6 to 7.
- Promptly bag and remove infected plants, including roots to prevent spread.
- Remove and/or plow in remaining plant debris immediately after harvest to encourage decomposition.
- Reduce transmission year-to-year by using new stakes or new strings each year.
- Avoid wounding young transplants during planting.
- Use booties or disinfest boots by washing them between high tunnels. Begin working in cleanest tunnels first.
Chemical control
There are no fungicides that are effective for managing Fusarium crown and root rot.
Reviewed in 2016
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