Plant Health Initiative

Management of Charcoal Rot

Management of charcoal rot requires an integrated approach.

Death of young plant due to charcoal rot infection under extreme heat and drought conditions. Click on image to view a larger version. Photo credit: Chris Little, Kansas State University.

Reduce drought stress

Plants grown in conditions of high temperatures, drought, or poor fertility (too high or too low) are most susceptible.

Implement cultural practices that reduce plant stress, such as

• lower plant populations
• conservation tillage practices that conserve soil moisture
• good weed control
• irrigation
• optimized fertility levels, especially phosphorus. Good fertility won't control charcoal rot, but it can reduce disease severity.

Select less susceptible soybean varieties

Although no soybean varieties have complete resistance, varieties can differ in their levels of susceptibility to the disease. Select soybean varieties that are not highly susceptible to charcoal rot. Plant high quality, disease-free soybean seed.

Plant the fullest-season varieties that are practical. Plants are most susceptible to charcoal rot at the beginning at flowering. The longer-season varieties tend to flower later and are in a vegetative growth stage during the early part of the hottest, driest portion of the growing season.

 

Practice crop rotation

In fields with a history of charcoal rot, rotate out of soybeans for two years. Small grains such as wheat and barley are a good rotation choice, as they are poor hosts for the pathogen.

The charcoal rot pathogen has a wide host range that include corn, dry beans, sorghum, sunflower, alfalfa, and white clover.

Other practices

Tillage does not affect the charcoal rot pathogen, as the microsclerotia can survive for a long time in soil.

Foliar and seed treatment fungicides do not provide protection against charcoal rot.

 

Contributors

Doug Jardine , Kansas State University
Chris Little, Kansas State University
Craig Grau , University of Wisconsin-Madison 
Jason Bond , Southern Illinois University
Carl Bradley, University of Illinois