Stem rot disease of Withania somnifera caused by Sclerotinia sclerotiorum in India

Severe infection of stem rot was observed on plants of Withania somnifera during January and February of 2020 and 2021. Initial symptoms appeared on the plants showing paleness at infected areas, cottony, fluffy white mycelia was observed on the leaves, stem and inflorescence. In advanced stage of infection wilting of stem and defoliation was observed leading to partial or whole plant death. Based on its morphological and molecular traits, the fungus was identified as Sclerotinia sclerotiorum. Pathogenicity test was performed under controlled conditions resulting in similar symptoms to those observed in field. To the best of our knowledge, this is the worldwide first evidence of S. sclerotiorum causing stem rot disease on W. somnifera.