Plant Health Initiative

Charcoal rot - Management

Reduce plant stress

Plants grown in conditions of high temperatures, drought, or poor fertility (too high or too low) are most susceptible. Therefore, any cultural practice that minimizes plant stress, especially moisture stress, will reduce the risk of charcoal rot.

Practices that lower plant stress include lowering plant populations, providing irrigation, controlling weeds, and optimizing fertility levels, especially phosphorus. Good fertility won't control charcoal rot, but it can reduce disease severity.

Variety selection

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.

Rotation

In fields with a history of charcoal rot, rotate out of soybeans for two years. Small grains and corn can be planted during the two-year interval between soybeans. Corn is a host for the pathogen, but generally supports lower populations of microsclerotia in the soil than does soybean.

Tillage

Plowing or other tillage does not readily destroy the charcoal rot organism because microsclerotia can survive for a long time in soil.

There are no chemical treatments for charcoal rot in soybean.

Contributors

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