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.