Sclerotinia timber rot has been widely reported on high tunnel tomato this year, and has been found on tobacco and cucumber in greenhouse systems. It also occurs on peppers and ornamentals.
Like Pythium, Sclerotinia is benefited by wet weather and moderate (50° to 70°F) temperatures. Because of this, Sclerotinia usually only produces spores at the beginning of the season, which may be blown into tunnels or greenhouses by wind. Although it does not produce secondary spores, Sclerotinia is important because it may infect many crops and because its sclerotia (hardened balls of fungal mycelium) may survive in a dormant state for up to 7 years in soil.
Disease Management Approaches
Preventing the introduction of Sclerotinia
- Completely remove previously infected plants and plant debris from field or high tunnel area.
- Sweep fabric floor to remove any sclerotia and disinfest using 10% bleach.
- Keep area around high tunnel free of broadleaf weeds.
- Ensure adequate fungicide spray coverage of stems.
Management when Sclerotinia is identified
- Remove from area by carefully digging up entire infected plant, bagging, and disposing far away (at least 500 feet) from areas that will be cropped with susceptible plants.
- In greenhouse or high tunnel, protectant sprays with mancozeb may prevent Sclerotinia infections, and Fontelis used for Botrytis management may have some activity.
- In the field, Cabrio or Priaxor are labeled for management of Sclerotinia.
By Emily Pfeufer, Extension Plant Pathologist