Assessment of Brown Spot Disease (Bipolaris oryzae) Severity in Paddy Fields of Prayagraj District, Uttar Pradesh, India

Brown spot disease, caused by the fungus Bipolaris oryzae, poses a significant threat to rice production. This study assessed the severity and distribution of the disease in the paddy fields of the Prayagraj district, Uttar Pradesh, India, over two consecutive Kharif seasons (September 2011 and September 2012). A survey was conducted across eight tehsils (Karchhana, Soraon, Handia, Phulpur, Bara, Meja, Sadar, and Koraon), with five villages randomly selected from each. Disease severity was quantified using the Percent Disease Incidence (PDI) method. The pooled mean PDI across the tehsils ranged from a low of 25.08% in Phulpur to a high of 47.24% in Meja. High disease incidence was also noted in Soraon (45.57%). The village-level data revealed the highest pooled PDI of 50.0% in Dihi Khurd (Meja) on the PB-1509 variety. The disease was prevalent during both the Post tillering and Panicle initiation stages. The consistent and high incidence of brown spot disease in tehsils like Meja and Soraon confirms its endemic status in the region and underscores the urgent need for targeted integrated disease management strategies, including the development and deployment of resistant rice varieties.