In a recent statement, the Punjab Agricultural University (PAU) in Ludhiana issued a warning to farmers about the potential threat of dwarfing disease in the upcoming rice cultivation season. The university's scientists have identified the cause of the disease as the Southern Rice Black Streaked Dwarf Virus (SRBSDV), which has been detected in India for the first time.
During the kharif season of 2022, reports of this mysterious dwarfing disease started emerging from the northern region, affecting hundreds of acres in the rice-growing belt. PAU's investigations confirmed that the SRBSDV was responsible for the stunted growth observed in the affected plants, despite the application of recommended nutrient dosages.
PAU Vice-Chancellor, Satbir Singh Gosal, emphasized the need for caution as the paddy season approaches and transplantation begins in mid-June. He urged farmers to take preventive measures to avoid encountering the same problem this year. The impact of the virus was witnessed in approximately 34,000 hectares of land in Punjab alone.
Dr. Ajmer Singh Dhatt, the Director of Research at PAU, described the typical symptoms of the disease, stating that affected plants exhibited stunted growth and had shallow roots, ultimately withering away. These symptoms were observed across various cultivated rice varieties in farmers' fields. Moreover, the stunting was more pronounced in early-sown paddy crops compared to the late-sown ones.
The disease incidence of stunted plants ranged from 1 to 6% in the districts of Fatehgarh Sahib, Patiala, SAS Nagar, Ropar, and Ludhiana. However, there were isolated fields where the incidence was observed to be higher. Dr. PS Sandhu, the Head of the Department of Plant Pathology, highlighted that their scientists are actively conducting surveys in areas where the disease was observed last year. They are collecting samples of rice nursery plants to detect any latent infection of the virus.
Due to the virus being transmitted through a small insect called the White-backed planthopper (WBPH), Dr. Sandhu stressed the importance of regularly monitoring rice plants for the presence of this insect. He advised farmers to start monitoring their rice crop from the nursery stage, paying particular attention to the presence of WBPH.
For monitoring purposes, Dr. KS Suri, Principal Entomologist, suggested a simple method. Farmers can slightly tilt a few plants in the field and tap their base 2-3 times. If WBPH adults or nymphs are present, they will be seen floating on the water.
In case of their presence, Dr. Suri recommended managing WBPH by applying appropriate insecticides such as Pexalon 10 SC (triflumezopyrim) @94ml, Osheen/Token/Dominant 20 SG (dinotefuran) @80g, Chess 50 WG (pymetrozine) @120g, or Imagine 10 SC (flupyrimin) @300ml in 100 liters.
