First report of collar rot or rhizome rot disease of turmeric (Curcuma longa) caused by Sclerotium rolfsii in Tamil Nadu

Collar rot and rhizome rot disease was observed on turmeric (Curcuma longa L.) in Athimugam village, Krishnagiri district, Tamil Nadu. Infected plants showed yellowing and drying of foliage, collar region rot, white cottony mycelial growth, and mustard seed-like sclerotia, leading to wilting and toppling of plants. The pathogen was isolated on potato dextrose agar and identified as Sclerotium rolfsii based on cultural and morphological characteristics. Pathogenicity was confirmed through artificial inoculation under pot culture conditions, where typical symptoms developed within ten days, fulfilling Koch’s postulates. To our knowledge, this is the first report of S. rolfsii causing collar and rhizome rot of turmeric in Tamil Nadu, India. The study highlights the emergence of this soil-borne pathogen as a potential threat to turmeric cultivation in the region.