Prevalence and Distribution of Urd Bean Web Blight Disease (Rhizoctonia solani) in Tarai Region of Uttarakhand

Abstract

Aims: The present investigation was undertaken to study the severity and incidence of web blight in four districts i.e., Udham Singh Nagar, Nainital, Almora and Champawat of Uttarakhand. Study Design: Using RBD (Randomized Block Design). Place and Duration of Study: Periodic surveys were carried out in various black gram growing areas in the Tarai region of Uttarakhand during three consecutive Kharif seasons i.e. 2022, 2023 and 2024 from September to November. Methodology: In order to record the occurrence of disease, incidence and severity of web blight were recorded periodically in black gram fields in different localities surveyed at each location in a village, two fields 10 plants were selected randomly and in every field, using random sampling methods sampling was done at four corners, and centre of the field (“X” fashion) taking an area of 1 m² at all the five positions. For all the survey locations, altitude, latitude, longitude, crop growth stage, percent disease incidence and severity of the disease was recorded. Results: The highest disease incidence and disease severity ranges in 2022, (76.95) to (10.92) and (79.20%) to (10.92%), in 2023, (80.86) to (10.58) and (80.67%) to (10.88%) and 2024, (83.01) to (9.86) and (77.13%) to (9.05%) were recorded in Pantnagar, followed by Nagla of Udham Singh Nagar. Conversely, the lowest disease incidence and severity was recorded in Puranpur, Haripur Roopsingh of Nainital and Matkota of Udham Singh Nagar. Conclusion: The extensive survey revealed web blight across most of the black gram fields in the region. In 2022 2023 and 2024, disease incidence and severity varied across locations, with Pantnagar consistently showing the highest values. The study also observed a correlation between disease occurrence and cropping patterns, with sole cropping areas experiencing higher incidence and severity.