ProMED
http://www.promedmail.org

Source: ChiniMandi [summ. Mod.DHA, edited]
https://www.chinimandi.com/motihari-scientists-inspect-sugarcane-fields-advise-farmers-on-crop-management/

A team of scientists from the Sugarcane Research Institute, Pusa, visited sugar cane farmers under the "Monitoring and Advisory Services for Sugarcane in Bihar" project. They inspected sugar cane fields planted in the autumn season and shared techniques to improve farming practices.

The problem of "red rot," a major disease that was severely damaging the crop, was brought to the notice of the farmers. A plant disease specialist suggested seed and soil treatment with biocontrol agent trichoderma. He also recommended the application of green manure to the soil in addition to other sustainable measures to control the disease.
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Communicated by:
ProMED

[Red rot disease of sugar cane is caused by the fungus _Colletotrichum falcatum_ (previously _Glomerella tucumanensis_). It is one of the oldest known diseases of the crop occurring in most cane growing countries, but continues to be a threat in a number of regions. Early symptoms are difficult to recognise; they may include discolouration; red streaks on midribs; leaf lesions; drooping of young leaves; withering of stalks. Symptoms expand until all stalks of the plant die; they collapse within 4 to 8 days. Affected stalks show an internal dull red discolouration interrupted by occasional white patches characteristic of the disease; they may also contain large cavities. Seed pieces may rot completely. Symptoms are highly variable depending on the host variety and environmental conditions. In tolerant varieties, the infection remains largely confined to the internodes.

Several pathogenic strains of the fungus have been reported from many countries. Climatic factors affect both the spread and severity of red rot. The disease is favoured by excessive soil moisture, drought and low temperatures. In addition, the nutritional state of the host may affect fungal growth. The pathogen can be spread by wind, rain, irrigation water, infected planting material and crop debris. Spores may survive in the soil to infect planted seed pieces. Hosts other than sugar cane are not considered important inoculum sources.

Disease management may include use of clean planting material, phytosanitation and cultural methods. Quarantine measures must be applied to prevent movement of infected cane setts to new areas. Hot water or fungicide treatments can be applied to setts before planting, but foliar fungicides have proven ineffective. The use of resistant varieties is the most effective method of control. Host factors determining resistance to red rot are not fully understood, but breeding programmes using intergeneric and interspecific crosses of _Saccharum_ spp. are being used to develop economically viable red rot-resistant or tolerant varieties. Research on biocontrol agents (such as _Trichoderma_ spp. mentioned above) is also being undertaken.

In India, red rot has caused extensive damage in the past and was responsible for the elimination of many elite sugar cane varieties. New varieties developed by ICAR (Indian Council of Agricultural Research) are being rated in their levels of resistance to prevalent races of _C. falcatum_ based on experimental trials.

The fungus has also been reported as a cause of anthracnose of maize and can also affect sorghum.

Pictures
Red rot symptoms on sugar cane:
https://istudy.pk/wp-content/uploads/2016/10/2192_0.jpeg,
https://pestoscope.com/wp-content/uploads/2020/05/Sugarcane_Red-rot_2.jpg and
https://image.slidesharecdn.com/narayanplantpathology-170510070936/95/red-rot-of-sugarcae-7-638.jpg

Links
Information on red rot of sugar cane:
https://doi.org/10.1079/cabicompendium.25361,
http://eagri.org/eagri50/PATH272/lecture06/001.html,
https://agritech.tnau.ac.in/crop_protection/sugarcane_diseases/sugarcane_d4.html and
https://doi.org/10.4172/2157-7471.1000S1-003 (review)
_C. falcatum_ taxonomy and synonyms:
https://indexfungorum.org/Names/NamesRecord.asp?RecordID=157602 and
https://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=157602
Information on ICAR & Indian cane varieties via:
https://sugarcane.icar.gov.in/
- Mod.DHA