Bean IPM

Legume ipmPIPE Diagnostic Series

Southern Blight

Sclerotium rolfsii


Infection appears as a slight yellowing on lower leaves, water soaking and darkening of hypocotyls above the soil line, and destruction of the cortex; followed by wilting, leaf drop and death. Small (1-2 mm diam), spherical, brown sclerotia form on coarse mycelium at the plant base. The pathogen has a very wide host range.

Factors favoring
  • Presence of previously infested crop debris
  • Lack of crop rotation
  • Poor sanitation of previous legume and weed debris
  • Contaminated seed
  • Susceptible varieties
  • Moderate to high moisture conditions favor slugs
  • Infection at V2 – R2 results in plant death, and/or reduced pod set, poor seed fill, and yield loss
Southern Blight
Southern Blight at the base of the stem
Additional Resources

H. F. Schwartz, Colorado State University and S. K. Mohan, University of Idaho

Photo credits

H. F. Schwartz, Colorado State University,