Root rot: neem cake 150 kg/ha to the soil and seed treatment with Trichoderma asperellum 4 g/kg (or 5 kg/ha to the soil). Chemical drenches and sulphur options for root rot and powdery mildew are also listed — ask your officer.
Pending expert review
Source
Crop Production Guide – Horticulture Crops 2020 (Directorate of Horticulture and Plantation Crops, Tamil Nadu & Tamil Nadu Agricultural University (TNAU)), Fenugreek – Plant protection, p. 188