Fusarium sacchari (E.J. Butler) W. Gams · formerly or also: Cephalosporium sacchari, Gibberella sacchari (sexual stage)
Sugarcane wilt is a stalk disease in which canes stop growing, the leaves yellow and dry, and the inside of the stalk turns purplish-brown, pithy and hollow. It shows up late, usually four to five months after planting, often in the same fields as red rot and after spells of drought or waterlogging. It is a major disease in parts of South Asia, where it is ranked second only to red rot in some sugarcane belts, and it has more recently been confirmed in China and north-east Africa.
Sugarcane wilt is caused by Fusarium sacchari (E.J. Butler) W. Gams, a fungus (soil- and sett-borne vascular and stalk pathogen) (order Hypocreales, family Nectriaceae).
Older or alternative scientific names: Cephalosporium sacchari, Gibberella sacchari (sexual stage).
Wilt was first described from South Asia early in the twentieth century and is best documented there. The causal fungus has been confirmed by molecular methods in South Asia, southern China and Sudan, and Fusarium sacchari itself is recorded in sugarcane in other tropical and subtropical regions, although wilt surveys outside South Asia are few.
| Region | Status |
|---|---|
| South Asia | Widespread and important; incidence in individual sugar-factory zones ranges from a few per cent to well over half of the canes in bad years |
| East Asia | Wilt caused by F. sacchari first reported from southern China in 2020 |
| North-east Africa | Reported together with root borer damage from a large irrigated estate in Sudan in 2022 |
| Other sugarcane regions | F. sacchari is present; wilt records are scattered and its importance is poorly known |
A Fusarium fungus that grows as white to pinkish cottony mycelium inside the pith of diseased canes. Under the microscope it produces small oval single-celled spores (microconidia) in false heads and on branched conidiophores, and fewer curved, several-celled macroconidia. It does not form chlamydospores, which helps separate it from Fusarium oxysporum. Reliable identification needs isolation and DNA sequencing, because several Fusarium species can be found in wilted stalks.
| Crop stage | What you see |
|---|---|
| Young crop (first 3-4 months) | Usually no visible symptoms; infection from setts and soil is already present. Germination may be poor and some young shoots die where infected seed cane was planted. |
| Grand growth and monsoon to post-monsoon period | Single canes or whole clumps stop growing; the crown leaves turn yellow and then dry from the tips and margins; the midribs often yellow first. Canes look shrunken and feel light. |
| Inside the stalk | When split, the internodes show light purple to dark reddish-brown discolouration of the soft tissue, a dry, pithy texture and boat-shaped hollow cavities in the middle of the internodes, sometimes lined with white cottony fungal growth. Diseased canes give off an unpleasant, sour smell. |
| Ratoon crop | Stools from infected plant crops sprout poorly and gaps appear in the row. |
The fungus survives in infected seed cane and in soil and crop debris. Planting infected setts carries it to new fields, where it moves up the vascular tissue of the growing stalk. Soil-borne inoculum enters through the roots and through wounds, especially those made by root borers, other boring insects and nematodes. The disease develops slowly and becomes visible only in older canes, particularly when the crop is stressed by drought, by waterlogging or by both in turn. Spores produced on dead tissue are carried in water and soil, and the same fungus can infect the leaf spindle to cause pokkah boeng.
| Stage | Duration | Notes |
|---|---|---|
| Survival in setts, soil and debris | Between crops; for at least one cropping season | Infected seed cane is the main long-distance source. |
| Entry through roots, wounds and planted setts | From planting onwards | Root borer and nematode injury increase entry. |
| Slow internal colonisation | About 4-5 months before symptoms appear | Stress during the monsoon and post-monsoon period hastens collapse. |
| Wilting, pith decay and cavity formation | Several weeks after first yellowing | Canes become light, hollow and unfit for milling. |
The disease is associated with the warm, humid monsoon and post-monsoon period of tropical and subtropical sugarcane belts. Precise temperature optima for infection under field conditions have not been published in a form that allows a simple rule; stress from drought followed by waterlogging is a more consistent predisposing factor than temperature alone.
One disease cycle per crop; the fungus carries over into ratoons and, through seed cane, into the next planting.
Planting seed cane from infected fields; drought during the grand growth period, waterlogging, or drought followed by waterlogging; heavy damage by root borers, termites and nematodes; susceptible varieties grown in the same fields for many years; and continuous ratooning. Wilt and red rot often occur together and the combined damage is worse than either alone.
There is no numeric economic threshold. Because infected canes cannot be cured, action is preventive: healthy seed cane, resistant varieties and avoiding crop stress. Field incidence surveys are used to decide whether a variety should be withdrawn from an area.
Thresholds are local. They depend on crop price, control cost, variety and natural-enemy activity, so use the figure your local extension service publishes where one exists.
Wilted canes lose weight, juice and sugar. In inoculated field trials with 36 varieties in eastern India (2023-24), reductions caused by wilt ranged from 4 to 43 % in cane weight and from 7 to 49 % in sucrose, depending on variety. Germination and early shoot survival also fall when infected setts are planted. A report from China put losses on susceptible cultivars at about 10 %. Where wilt occurs with red rot, whole fields can become unfit for milling.
Control works best as a sequence: prevent, monitor, then act only when a threshold or a risk forecast says so, using the least disruptive option that works.
Fungicide sett treatment is used as one part of a programme based on healthy seed cane and resistant varieties; it cannot cure canes that are already wilted. What is registered differs by country and changes over time; follow the label and your local plant-protection authority.
| Scheme | Group | Mode of action | Notes |
|---|---|---|---|
| FRAC | 1 | Methyl benzimidazole carbamates (MBC) | Sett dip before planting; high resistance risk in Fusarium, so do not rely on it alone. |
Sugarcane (Saccharum hybrids) is the main host. The same fungus, Fusarium sacchari, also causes pokkah boeng (a twisting and rotting of the young leaf spindle) on sugarcane, so the two diseases can occur in the same crop. Other Fusarium species of the same species complex attack maize, sorghum and many other grasses.
How to grow the crop well is the first line of defence. Laisha's free grow guides cover each crop from sowing to harvest:
Written by Laisha from the sources above, in its own words. This page is general reference, not a prescription: confirm identification locally and follow the label and your plant-protection authority.
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