Pythium Stalk Rot
Symptoms
- Usually limited to individual plants in small areas.
- Infection usually limited to first internode above the ground.
- Infection site will appear brown, water soaked, soft, and collapsed.
- Pith tissue may completely rot, stalks may be twisted or distorted,
but will not completely break off. - Vascular bundles remain intact, and the plant may remain green for
several weeks.
Pathogen Involved
- Pythium aphanidermatum (an oomycete fungal-like pathogen)
- Overwinters as oospores in the soil.
Time of Occurrence
- Can occur prior to flowering, but mainly infects after pollination.
Conditions Favoring Disease
- Extended periods of hot (90°F or more) and wet weather.
- Poor soil drainage
- High humidity
Disease Management
- Improve soil drainage.