Rice blast, a fungal disease affecting paddy, is haunting farmers who had raised “Manuvarna”, a new rice variety released by the Kerala Agricultural University recently, on more than 250 acres in Wayanad district.
K. Kesava Marar, president of the Cheekkallur Padashekhara Samiti, cultivated the new rice variety on 70 acres of rented land after learning from some farmers in Palakkad district that it had given higher yields than the traditional rice varieties.
Mr. Marar, along with 60 other farmers of the samiti, procured the 4,600 kg of seeds from the Kerala Agricultural University at a cost of ₹42 kg.
However, they noticed a few weeks ago that the crop cultivated on more than 250 acres of land was damaged owing to the blast disease.
Mr.Marar said he had spent around ₹35,000 an acre for the cultivation, including rent, but, he could not recoup one-third of it after the harvest. The condition of other farmers who had cultivated the crop under the Panamaram, Kaniyampetta, and Mananthavady Krishi Bhavans was not different, he said.
When a group of scientists of the Regional Agricultural Research Station (RARS) at Ambalavayal visited the site recently, they noticed that the crop in the grain filling stage was damaged by the blast disease and more than 150 acres of area has been affected under the Cheekallur Padashekara Samiti.
The blast disease is caused by the fungus Pyricularia oryzae which is non-systemic in action. The spores of the fungus could have been released from hosts like Purple nutsedge and Echinochloa crusgalli (Muthanga and Kavada respectively in local parlance) which are abundantly present in the paddy fields, bunds, and on sides of irrigation channel of the affected area. This would have resulted in an increased concentration of spores in the air. Relative humidity of more than 93% and rainfall below 5 mm per day are the major predisposing factors especially during the mid tillering stage of the crop for the incidence of the blast, RARS sources said.
The ‘Manuvarna’ variety of paddy was released for the low lands of Kerala, especially for the kole lands, wetland ecosystem, K. Ajith Kumar, Associate Director, RARS, told The Hindu.
Adoption of prophylactic measures of management would have substantially reduced the severity of blast disease incidence, Dr . Ajithkumar said. However, such measures were not taken properly in the affected area which led to severe damage due to the incidence of neck blast, he said.
