Charcoal Rot

Tiny dark fungal structures on stem and root tissue look like charcoal dust. Click on image to see larger version. Photo © Doug Jardine, Kansas State University

Charcoal rot is a root disease caused by the fungus Macrophomina phaseolina. The pathogen is extensively distributed in soils worldwide. It can infect over 500 different kinds of plants, including important agronomic crops such as soybean, corn, grain sorghum and sunflowers.

Although the initial infection occurs in the spring when soil moisture is high, symptoms of charcoal rot develop in the hottest, driest part of the growing season. It is more prevalent in southern states, but can occur anywhere when hot, dry conditions prevail.

The fungus causes a general root rot in soybean, infecting the roots and lower stems. It was named from the fact that infected tissues look as if they have been dipped in charcoal dust.

Information on these pages is from the cooperative effort of researchers throughout the North Central states. Information from this site can be copied and distributed for educational use. Please credit the source with our name and URL: NCSRP Plant Health Initiative at www.planthealth.info. Please do not use copyrighted photos without permission.