Contagious fungal disease knocks UP’s blockbuster cane off its perch

A sugarcane variety that helped Uttar Pradesh beat Maharashtra to become the country’s largest producer of sugar is being knocked off its exalted perch by a contagious fungal disease. Extensive cultivation of the variety has made it acutely vulnerable and threatens its dominance. It has become a victim of its own success.

The sugarcane variety, Co 0238, developed by Bakshi Ram, the former director of the Coimbatore-based Sugarcane Breeding Institute, is cultivated in about 90 per cent of the cane area in western Uttar Pradesh, where cane cultivation is entrenched. Its share in the other regions of UP is a little less, but it’s still the single-largest variety. It has been threatened by red rot, a fungal disease, which entomologist M Thirumalai describes as “cancer of sugarcane”.

Extensive infestation

The fungal infestation is so extensive that replacement with other varieties was considered a more viable alternative at UP’s state-level varietal release committee meeting in August, says Deepak Guptara, Secretary-General of UP Sugar Mills Association.

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But farmers continue to grow this variety. “Actually, the yield of Co0238 is exceptionally higher than other varieties. If the infection is mild or negligible then growers prefer to grow this variety,” says Roshan Lal Tamak, Executive Director & CEO, DCM Shriram, which has four sugar factories in central UP. “In case of severe incidence, they opt for new varieties,” he says. Infection in seed, the time of planting, humidity and rainfall are factors that help the fungal infection to flare up.

The spread of fungal infection differs from one factory area to another. Around one central UP sugar mill, cane area is 91 per cent of total cultivated area, enabling fast spread of the infection. In another mill area, only 35 per cent of the cultivated area is under case, slowing the spread of the fungus.

Farmers might continue to grow Co 0238 despite risks, because they may not have obtained the seed of replacement varieties.

Co 0238’s advantages

Co 0238 has two properties that endear it to farmers and sugar mills: high yield and high sugar recovery. High yield is due to two factors: taller cane and larger diameter. Co 0238 is ‘medium-thick’ and is on average 2.5-2.75 cm in diameter. The varieties grown in UP previously were ‘medium-thin’ of 2-2.5 cm thickness. From about 3 per cent cane area in 2013-14, Co 0238 occupied 88 per cent of UP’s cane cultivation area in 2020-21.

Good agronomic practices allow the cane to grow taller and fatter. When the setts, as the seedlings are known, are planted with a gap of about nine inches between them, and in trenches four-five feet apart, the tillers or secondary shoots get ample room for growth and adequate sunlight, water and nutrients. The result is taller and heavier cane. Mustard, potato, peas or lentils is grown in the space between the rows early in the life of the crop for additional income.

The variety is also early maturing. This refers to early sugar concentration. When the crop is 300 days old, its sugar level is about 18 per cent. This rises to about 20 per cent one or two months later. When planted in trenches, four-five feet apart, Co 0238 gives an average yield of 810 quintals per hectare (q/ha), compared to 600 q/ha of the previous popular variety.

Sugar mills prefer the cane for early sugar accumulation. They start the crushing season with ‘ratoon’ cane, or the crop derived from coppiced cane (shoots emerging from stubble after harvesting).  The next in queue is spring cane, planted in February-March, which is harvested 11 months later. This combination resulted in average sugar recovery of 12 per cent going up to 14 per cent in UP in 2019, Bakshi Ram and his colleague G Hemaprabha wrote in a 2020 article in Current Science.

Though Co 0238 was officially released in 2009, it did not catch on till 2013-14. In that year, it was grown on 3 per cent of UP’s cane area. But it spread like oil slick on water and occupied slightly less than 88 per cent of UP’s cane area in 2020-21.

Ram says he has advised sugar mills to reduce the area under the variety. They must provide farmers with pure seed free of infection grown in nurseries or in tissue culture labs. The seed must be treated with fungicide before planting. The fields must also be treated with a bio-pesticide called Trichoderma. If a field is infected, no cane should be planted in it for one year. It’s best to grow paddy in it as water stagnant for four-five months kills the fungus.

There are replacement varieties too but they “cannot gain the same status” as Co 0238, says Tamak.

Farmer’s experiences

During a five-day visit to cane areas in Lakhimpur Kheri and Hardoi districts, this correspondent met farmers whose yields from Co 0238 were higher than the state average.

Anurag Shukla, 46, of village Udranpur in Shahbad tehsil of Hardoi, in 2021-22 had achieved a yield projected at 2,468 quintals per hectare in the sugar season which runs from October to September. He had participated in a cane competition and the crop cutting exercise was done by the state cane department. The tallest cane was 21 feet long, and no cane was less than 18 feet in length, Shukla said. Some of them weighed 3.5 kg. Shukla’s actual output was less as the area of the contest plot was five bighas (six bighas is an acre, and 2.47 acres is a hectare). But his average yield of his farm over the past three years was 986 q/ha.

Even those who are not as competitive as Shukla, achieve higher than average yields with good farm management practices. Paramjeet Kaur of village JIgniya Shivraj in Misrikh tehsil of Sitapur district has harvested 875 q/ha over the last three years. Higher yield from large farms is difficult because they cannot be given the same care as small plots. Kaur is virtually unlettered. She had to take the plunge into farming after her husband passed away eight years ago. She learnt the ropes on the go and does all farming operations, except planting, with a small tractor.

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High yield in UP

Because of Co 0238, UP’s sugar production over the past eight years averaged 96 lakh tonnes per year, higher than Maharashtra’s average of 86 lakh tonnes per year during the same period. Its sugar recovery rose steadily from 9.07 per cent in 2011-12 to 11.73 per cent in 2019-20. Maharashtra’s has hovered around 11.5 per cent. The tropics are better suited for cane cultivation than the sub-tropics, where winter inhibits growth.

Co 0238 contributed in a big way to making India sugar surplus. But Ram says that area under the variety should not be more than 50 per cent. The sunshine days of UP sugar mills might not return unless comparable substitutes are found. But India may not be short of sugar because of cane area expansion in Karnataka, Maharashtra and Tamil Nadu. The first advance estimate of sugar this year is 4,650 lakh tonnes, against the fourth estimate of 4,318 lakh tonnes last year.