Vol. 9, Issue 4, Part L (2025)

Twenty isolates of Sclerotium rolfsii were collected from major brinjal-growing districts of Tamil Nadu, including Cuddalore, Salem, Dindigul, and Erode. The isolates were named as Sr1 to Sr20, and were subjected to a pathogenicity test to confirm their virulence and adherence to Koch postulates. The results confirmed the pathogenicity of all isolates, with distinct symptoms of collar rot observed on inoculated plants and the highest disease incidence of 45.59% was recorded in the isolate Sr3 and the least disease incidence of 16.07% was recorded in the isolate Sr17. Further studies were conducted to determine the susceptibility of brinjal plants at different growth stages. The findings revealed that younger plants were significantly more susceptible to S. rolfsii infection compared to older plants. This increased susceptibility in the early stage highlights the critical need for early-stage management practices to mitigate losses caused by this pathogen in brinjal cultivation.