Common crops affected
- Vegetables
- Potato
- Cotton
- Turf
What is it?
Rhizoctonia is a widespread soil fungus that attacks seedlings (damping-off), stems at the soil line (canker), roots and tubers, and turf (brown patch). It survives in soil and debris and is favoured by warm, moderately moist conditions.
How to identify it
- Seedlings collapsing with reddish-brown, sunken cankers at the soil line (post-emergence damping-off).
- Sunken stem/root cankers and brown root rot; in potato, dark 'black scurf' sclerotia on tubers.
- Patchy stunting and uneven stands; in turf, circular brown patches.
- Web-like brown mycelium on stems/soil under humid conditions.
Life cycle & spread
Survives in soil and debris as mycelium and sclerotia; infects seedlings, stems and roots directly; favoured by warm soils and crop debris; spreads on contaminated soil, media and tools.
Conditions that favour it
Warm, moderately moist soils; crop debris; compacted or crusted soils; continuous susceptible cropping.
Damage and how it spreads
Kills seedlings (stand loss), cankers stems and rots roots/tubers (reducing yield and storage quality), and damages turf — with the biggest impact at establishment.
Monitoring & scouting
Watch emergence and seedling vigour; check stem bases and roots of stunted plants; assess soil debris and history in problem areas.
How to control it
- Use clean media and sanitation, manage residue and soil moisture, support a healthy/competitive root zone, and apply protectant programs preventively at the seedling stage.
- Established rot can't be reversed — 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 seedling-protection and soil-health approach. - Charge Bioboost — soil inoculant that builds a competitive, biologically active root zone to help suppress soil pathogens and support seedling establishment.
| Role | Product | Use |
|---|---|---|
| Primary control | Spore Control | |
| Also apply | Charge Bioboost |
Preventing it next season
Clean media/tools, residue and moisture management, healthy/competitive soil biology, rotation, and preventive protection at establishment.
Claims and product availability vary by jurisdiction. Always read and follow the product label.