An Investigation on the Pathogenicity of Sclerotial wilt Infecting Jasminum sambac (L). Aiton

Abstract

This study was aimed to investigate the occurrence, pathogenicity and severity of Sclerotium spp. induced wilt in Jasminum sambac (L.) Aiton from Tamil Nadu and to evaluate oxalic acid degradation and disease suppression under controlled conditions. The research utilized a completely randomized design (CRD) for the experiments conducted. The experiment was conducted during the year 2024 to 2025 at SRM College of Agricultural Sciences in Chengalpattu district of Tamil Nadu, India. Infected J. sambac plants expressing typical wilt symptoms were collected, and the pathogen was isolated on PDA medium. Morphological traits such as mycelial growth and sclerotia characteristics were examined. Pathogenicity was confirmed by artificial inoculation and re-isolation. Oxalic acid, the virulence factor produced by the fungus was quantified and its degradation potential by rhizosphere antagonistic bacteria was evaluated in vitro. Pot culture experiments were conducted with varying sclerotia loads (2, 10 and 20 per pot) for different inoculum density. Sclerotium spp. was consistently isolated from diseased samples and produced abundant white mycelium and mustard-sized sclerotia. Pathogenicity tests confirmed its virulence, with higher sclerotia loads causing increased wilt incidence. Oxalic acid was detected in culture filtrates and the selected MS13 bacterial isolate effectively degraded. The study confirmed Sclerotium spp. as the causal agent of jasmine wilt in Tamil Nadu. Biocontrol agents capable of degrading oxalic acid may offer an effective disease management strategy. The effective bacterial isolates identity will be studied in future and will be exploited as an efficient biocontrol agent.