Red Rot (Sugarcane)

Red Rot of sugarcane is a highly destructive fungal disease caused by the specialized ascomycete pathogen *Colletotrichum falcatum* (teleomorph *Glomerella tucumanensis*). Often referred to as the 'cancer' of sugarcane, it is a major threat to sugarcane crops across tropical and subtropical regions. The fungus behaves as a vascular parasite, invading the internal stem tissue, breaking down sucrose, and blocking water transport. If left unchecked, it causes internal rotting, drying of stalks, and complete collapse of the sugarcane plant.

Identifying red rot involves examining both leaves and split stalks. The earliest external symptom is the yellowing and wilting of the third or fourth leaves from the top, which gradually dries up along the margins. The most definitive diagnostic cue is revealed by splitting the sugarcane stalk longitudinally: the internal pith turns bright red with characteristic white horizontal patches running crosswise. Affected stalks emit a sour, acidic alcohol-like odor due to sucrose fermentation, and the rind eventually sinks and shrivels.

The red rot pathogen targets commercial sugarcane and related grass species.

The fungus overwinters in infected crop debris, stubble, and seed setts. It spreads via water splash, rain, and contaminated harvesting tools, entering stems through node cracks and boreholes made by sugarcane stem borers. Organic management focuses on planting certified disease-free seed setts, crop rotation with paddy or green manures, and using hot-water treated setts. Chemical control includes treating setts with carbendazim or thiophanate-methyl before planting. For more crop health resources, check our Plant Disease Identifier Hub, or explore similar fungal profiles like Rust Disease, Root Rot, and Loose Smut.