Pythium Seedling and Root Rot
Symptoms:
- Pythium can attack and rot seeds and seedlings prior to emergence, and can cause post-emergence damping off under wet conditions.
- The characteristic symptom of most Pythium infections is soft, brownish-colored, rotting tissue.
- In established plants, secondary roots can be soft and rotted and plants may be stunted or killed in some cases.
- Phytophthora is a related pathogen that causes similar symptoms and the two can only be differentiated with laboratory examination.
Pathogen Involved:
- Pythium infects at all stages of development, and is active in wet soils.
- Pythium is a soilborne, fungal-like pathogen. Several different species of this pathogen damage soybeans.
- The various species of Pythium that infect soybean have a wide host range that can include corn and many other crops.
Time of Occurrence:
- Spring and early summer, although infection can also occur later in the season.
Conditions Favoring Disease:
- The disease occurs in wet and cool conditions and in low, poorly drained areas, particularly on clay, compacted soils
Disease Management:
- Plant in soils warmer than 55°F.
- Resistant varieties are not available.
- Soil drainage should be improved if possible, and low areas of fields should be avoided, especially if a field has a history of seedling or root rot problems.
- Some seed treatments can reduce seed and seedling rot.