Red rot (sugarcane)
Sugarcane’s most destructive disease — reddened, rotting internal tissue with white crossbands and a sour smell that dries the cane and slashes sugar recovery.
- Pathogen
- Fungus (Colletotrichum falcatum)
- Spreads by
- Infected seed setts; debris; soil; injuries
- Favoured by
- Waterlogging, injuries & susceptible varieties
- Main risk
- Cane dries; heavy yield & sugar-recovery loss
Overview
Red rot is historically the most destructive disease of sugarcane in India — it has wiped out whole varieties. The fungus rots the internal tissue of the stalk: when a diseased cane is split lengthwise, the inside is reddened, usually broken by patches or crossbands of white, and gives off a sour, alcoholic smell. Outwardly the crop shows drooping, yellowing and drying of the top leaves, and the affected canes dry up, become hollow and lightweight.
The disease attacks the standing crop and destroys both cane weight and, critically, sugar recovery, because it inverts and ferments the stored sugar. It is spread mainly through infected seed setts, and also survives on diseased debris and in the soil; injuries (including borer holes) and waterlogging make infection worse. Because there is no effective cure once the internal rot is advanced, management is built on resistant varieties, healthy disease-free seed, sett treatment and field sanitation.
How to identify it
- Split the stalk lengthwise: reddened internal tissue, usually crossed by patches or bands of white, with a sour, alcoholic smell — the definitive sign.
- Top leaves drooping, yellowing and drying from the third or fourth leaf downward.
- Affected canes drying up, becoming hollow, lightweight and shrunken, often with reddish specks on the rind and lesions at the nodes.
- Patches of dried, dead clumps appearing in the field as the disease spreads.
What causes it and when
- The fungus Colletotrichum falcatum, carried mainly on infected seed setts and surviving on diseased crop debris and in the soil.
- Enters through wounds — cut ends of setts, borer holes, growth cracks and other injuries.
- Favoured by waterlogging, high soil moisture and monsoon conditions, and by growing susceptible varieties continuously.
- Builds up where diseased ratoons and debris are left, re-charging the field each year.
Cultural & organic control
- Grow resistant varieties and change the variety when a resistant one breaks down — the single most important step against red rot.
- Take seed setts only from a healthy, disease-free crop/seed nursery; never plant setts from a red-rot field.
- Rogue out and destroy diseased clumps and debris, and do not ratoon a diseased crop.
- Ensure good drainage (avoid waterlogging), rotate away from cane, and manage borers that open wounds.
Chemical control
- Treat seed setts before planting — a hot-water treatment and/or a recommended fungicide dip (e.g. carbendazim) to disinfect the setts.
- There is no effective spray to cure canes once the internal red rot is advanced — control is preventive.
- Follow moist-hot-air/hot-water sett treatment schedules where recommended for seed health.
- Confirm the current variety recommendation and sett-treatment schedule for your area with your local KVK/cane research station.
Prevent it coming back
- Base the crop on resistant varieties and healthy, treated seed from a clean seed nursery.
- Do not ratoon or take seed from a red-rot-affected field; rogue and destroy diseased clumps promptly.
- Fix drainage, control stalk borers, and rotate crops to run down soil- and debris-borne inoculum.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
My sugarcane is drying and the inside is red when I split it. What is it?
Reddened internal tissue crossed by white patches, with a sour, alcoholic smell, plus drying top leaves and hollow, lightweight canes, is red rot — the most destructive disease of sugarcane. There is no cure once the rot is advanced. Remove and destroy affected clumps, do not ratoon or take seed from that field, and next season plant a resistant variety with healthy, treated setts.
Why is red rot so damaging compared with other cane diseases?
Because it destroys the crop from the inside and hits both weight and sugar. As the fungus rots the stalk, the cane dries, goes hollow and loses weight, and — critically — it inverts and ferments the stored sugar, so sugar recovery crashes even in canes that still look partly standing. It has historically wiped out entire popular varieties, which is why resistant varieties and clean seed are treated as essential, not optional.
How do I stop red rot spreading in my field?
Start from clean seed: take setts only from a healthy, disease-free crop and treat them (hot-water and/or a fungicide dip) before planting. Grow a resistant variety and change it if it breaks down. Rogue and destroy diseased clumps, never ratoon a diseased crop, fix drainage to avoid waterlogging, and control borers that open wounds for the fungus. Confirm the variety and sett-treatment schedule with your KVK.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.