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Charcoal Rot
Causal Agent:
Macrophomina phaseolina
Symptoms and Signs:
- Brown-black lesions on cotyledons
- Seedling death
- Lesions on root, stem, pod and seed
- Microsclerotia in vascular tissue and pith
- Grey coloration of stems and roots
- Wilting
- Premature death
Macrophomina phaseolina microsclerotia in the outside (A, B and D) and inside (C) of soybean stems.
Charcoal rot symptoms in plots infested with Macrophomina phaseolina. Soybeans wilt and die prematurely.
Disease Management:
Cultural practices: Practices that reduce plant stress will contribute to charcoal rot management. These practices include: planting soybeans in no-tilled soil; maintaining soil moisture; ensuring adequate fertilization; reducing plant population density; and rotating to other crops to avoid continuous soybean cropping. Combining these cultural practices will reduce the buildup of inoculum and the impact charcoal rot can have on soybean yield.
There is no fungicide seed treatment effective for control of this disease. Even though partial resistance to charcoal rot has been identified, resistant commercial cultivars are not available yet.