Mite infestation and sheath rot spread in Kuttanad’s second-crop paddy fields

Farmers in Kuttanad region are growing increasingly concerned as a widespread rice leaf mite infestation, locally known as ‘Karaval’, affects second-crop paddy fields. The infestation was confirmed following a comprehensive field inspection conducted jointly by officials from the M.S. Swaminathan Rice Research Station, Mankombu, and the Kerala Centre for Pest Management (KCPM). Experts reported that the current weather pattern characterised by hot daylight hours coupled with intermittent rainfall has created ideal conditions for the rapid proliferation and spread of these mites.

The condition is caused by a species of mite scientifically named Oligonychus oryzae. Under the present climatic conditions, these pests lodge themselves inside the leaf sheaths of paddy plants, sucking the sap and rapidly multiplying. Furthermore, the mites share a symbiotic relationship with Acrocylindrium oryzae, the fungus responsible for sheath rot disease. This co-existence significantly escalates the incidence of sheath rot alongside the mite damage. The dual threat leads to severe grain discoloration and chaffiness, threatening a drastic reduction in overall crop yield and leaving farmers deeply worried.

Agriculture officials have advised farmers to closely monitor their fields and confirm any presence of pest damage, warning that the infestation could expand further if favorable weather persists. Farmers are urged to apply targeted pesticides strictly in accordance with expert advice. For further guidance and assistance, farmers can reach out directly to the State Pest Surveillance Centre or the Rice Research Station. The joint inspection team that evaluated the affected fields included scientists M. Surendran and Jyothi Sara Jacob from the Rice Research Station, along with KCPH deputy director P. Rajani and assistant director M.K. Rajani.