Paddy transplanting is running at full pace this monsoon season, and once the fields settle down, farmers will begin applying chemical fertiliser as well as sprays to keep pests and diseases in check. Among the diseases that trouble paddy growers the most at this stage is Khaira disease. It shows up first on the leaves, turning them yellow before they eventually wither, and that stalls the growth of the whole plant. This is exactly why farmers are being urged to start watching their fields closely the moment the seedlings take root, so that the symptoms are caught early and treated before the damage spreads any further.
Why do paddy leaves start turning yellow?
Khaira disease is mainly linked to a shortage of nutrients in the soil, and zinc in particular. In several regions, the soil is already deficient in zinc, and that is precisely why symptoms of Khaira disease can appear in a paddy field within just 20 to 25 days of sowing. The risk climbs even higher in fields where the soil is alkaline or carries a heavy calcium content, because such soil makes it difficult for the crop to absorb whatever zinc is available. That combination is also why the disease tends to spread across wide stretches of paddy fields every monsoon, and why farmers who miss the early signs often end up counting significant losses by the time the crop matures.
How to identify the symptoms of Khaira disease
On an infected plant, the leaves first take on a light brown and reddish tinge, which is why catching the disease early matters so much. As the infection progresses, small pale yellow spots begin appearing on the leaves before darkening into a brownish shade. Compared with healthy paddy, a plant affected by Khaira disease stays visibly stunted, and even its roots turn a brownish colour instead of the usual white. Farmers are advised to start treatment the moment any of these signs show up, because once the disease is allowed to progress unchecked, the plant's growth can come to a complete stop and the eventual yield takes a direct hit.
A zinc sulphate spray offers an effective fix
Dr. A.K. Singh, an agricultural scientist posted at the Krishi Vigyan Kendra in Sultanpur, said that if symptoms of Khaira disease appear in a paddy field, farmers should dissolve 5 kilograms of zinc sulphate together with 20 kilograms of urea in 1,000 litres of water to prepare a solution, and then spray it across the paddy crop calculated at the rate of one hectare. "Spraying this solution brings down the effect of Khaira disease considerably, and it does not come in the way of the plant's growth," Dr. Singh said. He added that farmers who keep an eye on their fields from the very start of transplanting, and who apply this remedy as soon as symptoms appear, stand a much better chance of protecting their paddy crop from serious damage this season.
