The pathogen responsible for charcoal rot soybean is

The pathogen responsible for charcoal rot soybean is Macrophomina phaseolina.
Charcoal rot is a soilborne root and stems disease of soybean that develops in the mid to late summer when plants are under stress, especially heat and drought stress.
Charcoal rot is caused by the soilborne fungus Macrophomina phaseolina. This pathogen has a wide host range that includes corn, sunflower, and some weeds.
The fungus overwinters in the residue of host tissues and can survive for at least two years in dry soil.