Source: Devdiscourse [summ., edited]
The Punjab government has asked that a survey be conducted by district administrations to assess the damage caused to sugar cane crops by red rot disease. Reviewing the current situation after the outbreak of this disease, the Chief Agricultural Minister directed commissioners to work with the Punjab Agricultural University [PAU], cane experts and others, to find ways to combat the disease. The factors that led to a sudden attack by the fungus are to be explored. Cane growers are asked not to panic while authorities try to identify hotspot areas to effectively tackle the disease.
A scientist and sugar cane breeder at the Karnal regional centre of the Indian Council of Agricultural Research [ICAR], said this disease had already affected the sugar cane in Uttar Pradesh and Haryana states in the past due to the problem of waterlogging. The 'Co 0238' variety of sugar cane was found to be prone to this fungus and the farmers in these states who had suffered substantial losses were told not to grow this variety in the future.
[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 inter-generic and interspecific crosses of _Saccharum_ spp. are being used to develop economically viable red rot-resistant or tolerant varieties. Research on biocontrol agents 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. Co 0238 was developed by the Karnal centre of ICAR mentioned above and has been rated as 'moderately resistant' to prevalent races of _C. falcatum_, based on experimental trials. It is being praised as the 'wonder variety' due to increased cane yield and higher sugar content of crops. The variety is currently widely grown in several Indian states.
The fungus has also been reported as a cause of anthracnose of maize and it can also affect sorghum.
India (with states):
Red rot symptoms on sugar cane:
Information on red rot of sugar cane:
Information on the Co 0238 cane variety: