Fusarium crown and root rot
The fungus Fusarium oxysporum f. sp. radicis-lycopersici (FORL)
Tomato, pepper, eggplant, and a number of common weeds. The complete host range is not known.
Signs and symptoms
- Stunted, yellowed seedlings
- Lower leaves turn yellow and drop prematurely
- Plant wilts and may die
- Chocolate brown lesion girdles the main stem just above the soil line
- Reddish to brown discoloration of the stem cortex when sliced lengthwise
- Rotted, discolored, and stunted roots
- 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.
There are some tomato varieties with resistance to FORL. In addition, susceptible varieties can be protected by grafting onto resistant varieties.
- 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.
There are no fungicides that are effective for managing Fusarium crown and root rot.