The spread of red rot in Uttar Pradesh in a very popular cane variety affirms once again that there is insurance in diversity.
Co 0238, developed by Bakshi Ram, former director of the Sugarcane Breeding Institute, Coimbatore, and released in 2009 for the north Indian states, has spread in UP with the velocity of fake news on social media. In 2020-21, it covered 88 percent of UP's cane area, up from three per cent in 2013-14.
This is because of two reasons.
Co 0238 is high yielding. With a diameter of about 2.5 to 2.75 cm, it is 'medium thick', and 0.25 cm thicker than 'medium thin' varieties. New agronomic practices like trench planting, spaced rows, furrow irrigation, trash mulching, application of farmyard manure and trichoderma, a beneficial microbe, make the cane grow tall and has raised its average yield to 820 quintals per hectare (q/ha) compared to the 600 q/ha yield of the previous popular variety.
Mills prefer the variety because of its high sugar content, which reaches 18 percent in 300 days. The higher the sugar content, more the recovery. Average sugar recovery of UP mills has increased from 9.07 percent in 2010-11 to 11.73 per cent in 2019-20. It was 11.43 per cent last year. This has made UP, which produces the most amount of sugarcane, also the largest producer of sugar, beating Maharashtra. During the last eight years, UP's annual sugar production has averaged 96 lakh tonnes against 86 lakh tonnes of Maharashtra.
With extra care, farmers can get better yields than the average.
Anurag Shukla, 46, of village Udranpur in Shahabad tehsil entered a state-level competition last year with the intention of bagging a prize. His output from five bighas (six bighas is an acre) when projected on to a hectare (2.47 acres) amounted to 2,468 quintals. Officials of the state cane department did the crop cutting exercise and certified the yield. But the yield from the rest of his farm was less because he could not bestow the same care, so the average for his farm as a whole was 986 quintals/hectare. His uncle, Ravi Shankar Shukla, 64, got only 687 quintals/hectare though his land is of equivalent quality.
Being soft and high in sugar, the variety falls prey to red rot, which is described as cancer of cane. 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.
Ram, who works as a consultant to sugar mills post-retirement, says he has advised them to reduce the area under the variety. He tells them to 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 trichoderma, which feeds on the fungus. If a field is infected, no cane should be planted in it for one year. It's best to grow paddy in it as stagnant water kills the fungus.
Sustaining the variety is important till it can be efficiently replaced.
Raja Srivastava, who heads the corporate cane department at DCM Shriram, which has four sugar mills in central UP, says the spread is so extensive that its farmers are being advised to grow replacement varieties like Co 0118, CoLK 94184, Co 15923 and CoLK 14201. In its captive cane area, the share of Co 0238 had reduced to 54 percent from a peak of 88 percent.
There are farmers who continue to grow the popular variety. The infestation in their fields might be mild. Or they may not have an option. But it is commonly believed to be in decline. The yield is petering out and sugar levels are falling.
What are lessons?
It is clear that monoculture is never advisable. Farmers should grow a couple of varieties rather than bank on one.
Earlier, mills required farmers to plant early maturing, mid late and late maturing varieties to calibrate cane arrivals at the factory to the crushing schedule so that mills would remain in operation for 160-180 days a year. That practice must be revived.
Farmers must also adopt integrated pest management rather than relying on chemicals. Practising crop rotation, applying farmyard manure, treating the soil with beneficial soil microbes that check pests and pathogens and boost the immunity of cane, and using less harmful green label pesticides should form part of package of practices. And the share of no variety should exceed 50 percent.