A report of collar rot disease of Sugandh mantri (Homalomena aromatica) caused by Sclerotium delphinii in West Tripura state of India

During the year 2018-19, collar rot symptoms on Sugandh mantri plants were observed in fields in Agartala district of West Tripura state of India with a disease incidence of 20%. In the early stages of disease development, typical collar rot symptoms exhibited were dark brown necrotic lesions on the stem base. Later, the affected plants completely rotted and died. The diseased samples plated on PDA medium showed abundant, fluffy, dense white mycelia with reddish brown spherical sclerotia matching with the morphology of Sclerotium delphinii. The internal transcribed spacer (ITS) region of rDNA of the fungus was amplified and sequenced. The sequences revealed 99-100% identity with Sclerotium delphinii. The Koch's postulates were performed on three-month-old Sugandh mantri plants to confirm the pathogenicity of the isolated fungus. To the best of our knowledge, this is the first report of Sclerotium delphinii causing collar rot disease on Sugandh mantri plants in India.

Automated summary

During the year 2018-19, collar rot symptoms caused by Sclerotium delphinii were observed on Sugandh mantri plants in Agartala district of West Tripura state, India with a disease incidence of 20%. The symptoms included dark brown necrotic lesions on the stem base, which eventually led to plant death. The isolated fungus showed 99-100% identity with Sclerotium delphinii based on the amplified and sequenced ITS region of rDNA. Koch's postulates confirmed the pathogenicity of the fungus on Sugandh mantri plants. This is the first report of collar rot disease caused by Sclerotium delphinii on Sugandh mantri plants in India.