Caused by a soil fungus; waterlogging, poor drainage and injury at the collar favour it. Use disease-free planting material, remove infected plants, improve drainage, add neem cake, and apply Trichoderma harzianum 2.5 kg/ha mixed with 50 kg FYM. (A chemical soil drench is 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)), Elephant foot yam – Diseases (collar rot), p. 144
