Charcoal rot

Caused by: Macrophomina phaseolina
Problem Category: Fungal Disease
Symptoms: Symptoms are usually first apparent at the tasseling stage; plant stalks become shredded and pith is completely rotted with stringy strands of vascular tissue left intact; small, black fungal fruiting bodies are visible in the vascular strands and give the tissue a gray coloration; fungus grows into internodes of the stalk causing the plant to ripen early and causing the stalk to weaken; plant may break.
Comments: Emergence of the disease is favored by warm soils with a low moisture content; fungus overwinters in the soil and can also survive on other host plants which include sorghum and soybean.
Management: There are currently no available fungicides to treat the disease; avoid stressing plants by practicing good water management; rotating crops with small grains may help reduce disease incidence.