Stalk rot/Charcoal rot of Sweet Sorghum

 (Macrophomina phaseolina (Tassi) Goid)

 Symptoms

• Infected roots and lower stem of the infected plant show water-soaked lesions that slowly turn brown or black.
• Affected stalks become soft at the base and often lodge due even to moderate wind or by bending the plants. Thus premature lodging is the most apparent symptom of charcoal rot. When an infected stalk is split open, the pith is found disintegrated across several nodes.
• The cortical tissues are disintegrated and vascular bundles get separated from one another. Numerous minute, dark, charcoal-colored sclerotia of the pathogen are formed on these vascular tubes.
• Normally the disease appears during the post-flowering stage, but in some cases seedlings can also get infected.
  

   

  Fig. 1: Disease Symptoms
  

Control measures

• Charcoal rot is not a widespread disease. The disease appears only under terminal drought conditions, mostly in Rabi sorghum. If the crop is irrigated to alleviate moisture stress during flowering to grain filling stage, the disease can be prevented.
• The effect of disease on yield loss can be reduced by growing charcoal rot tolerant cultivars. Most sorghum cultivars with the stay-green trait have some level of tolerance to charcoal rot.