Charcoal stalk rot
Area of impact: Stalk
Description: Inner stalk deteriorates with gray or black discoloration inside the rind. This discoloration is caused by tiny black masses of fungal cells which can be seen with a hand lens. Charcoal rot can cause plant death.
Pathogen involved: Macrophomina phaseolina (a fungus)
Timing/Conditions: Occurs after pollination during hot and dry weather.
Contributing factors: Insect damage might increase risk of infection. Overwinters on crop residue.
Management practices: Plant hybrids resistant to Diplodia and Gibberella stalk rot reduce moisture stress and minimize early senescence of stalk tissue.