Stem and Root Rot or Charcoal Rot

Symptom

The disease is the most serious one affecting the crop at the later stage of growth. High temperature and water stress during growing season favours the pathogen's incidence. The yield loss occurred up to 60% due to root rot disease. The disease symptom starts as yellowing of lower leaves, follwed by dropping and defoliation. The stem portion near the ground level show dark brown lesions and bark at the collar region shows shredding. The sudden death of plants is seem in patches. In the grown-up plants, the stem portion near the soil level shows large number of black pycnidia. The stem portion can be easily pulled out leaving the rotten root portion in the soil. The infection when spreads to pods, they open prematurely and immature seeds shriveled and become black in colour. Minute pycnidia are also seen on the infected capsules and seeds. The rotten root as well as stem tissues contains a large number of minute black sclerotia. The sclerotia may also be present on the infected pods and seeds.