Common crops affected
- Vegetables
- Greenhouse crops
- Cucurbits
- Field crops
What is it?
Pythium species live in soil and water and attack germinating seeds, seedling stems at the soil line, and fine feeder roots. They are closely tied to the damping-off complex and thrive wherever soils stay wet and cold.
How to identify it
- Poor, patchy or failed emergence (seed and pre-emergence rot).
- Seedlings collapsing at the soil line with pinched, water-soaked stems (post-emergence damping-off).
- Brown, soft, mushy roots and easily detached root “sleeves.”
- Stunting and uneven stands in wet, cool, compacted or overwatered areas.
Life cycle & spread
Survives in soil and debris as resting spores; produces swimming zoospores in saturated soil that infect roots and seedlings. Spreads in water, splash and contaminated media or tools.
Conditions that favour it
Cool, wet, poorly drained or overwatered soils; heavy or compacted media; sowing into cold, wet ground.
Damage and how it spreads
Kills seeds and seedlings (reducing stands) and rots fine roots (reducing vigour and uptake), with the greatest impact at establishment.
Monitoring & scouting
Watch emergence and seedling vigour; check roots of stunted plants; assess irrigation and drainage in problem areas.
How to control it
- Manage irrigation and drainage, avoid waterlogging, use clean media and good propagation sanitation, and support a healthy, biologically active root zone.
- Focus on prevention and root protection.
Recommended Vegalab solution: Spore Control
Spore Control — natural broad-spectrum fungicide (thymol) used preventively where label-supported as part of a soil-health and seedling-protection approach. - Charge Bioboost — soil inoculant that supports a healthy, biologically active root zone, helping seedlings establish under disease pressure.
| Role | Product | Use |
|---|---|---|
| Primary control | Spore Control | |
| Also apply | Charge Bioboost |
Preventing it next season
Right-size irrigation, ensure drainage, use clean media and trays, sanitise tools, and avoid sowing into cold, wet soils.
Claims and product availability vary by jurisdiction. Always read and follow the product label.