Journal of Advances in Biology & Biotechnology

Zonate leaf spot of sorghum, caused by Microdochium sorghi, has emerged as an important foliar disease affecting sorghum production in humid and warm regions. The present study was conducted to assess the prevalence, incidence, severity, and spatial distribution of zonate leaf spot in major sorghum-growing areas of Uttarakhand and adjoining districts of Uttar Pradesh during two consecutive Kharif seasons (2021 and 2022). Field surveys were carried out across 62 villages covering nine districts of Uttarakhand and three districts of Uttar Pradesh. Disease incidence and severity were recorded following standard survey procedures, and severity was assessed using a 1–9 disease rating scale. During 2021, disease incidence and severity ranged from 10.0 to 88.0% and 5.12 to 83.33%, respectively, while in 2022, they ranged from 13.0 to 88.0% and 6.14 to 86.50%. The highest disease incidence and severity were consistently recorded in Pantnagar and Khatima of Udham Singh Nagar district, whereas the lowest were observed in Kiri Gaon of Pithoragarh district. One village, Devkatiya, remained free from zonate leaf spot during both years. Pooled analysis revealed that Udham Singh Nagar district recorded the highest mean disease incidence (78.94%) and severity (65.75%), while Pithoragarh district recorded the lowest mean incidence (5.75%) and severity (2.81%). Out of 62 surveyed fields, 61 were infected, indicating a high disease prevalence of 98.38%. The widespread occurrence and high prevalence of zonate leaf spot highlight its increasing importance as a major constraint to sorghum production. Variations in disease intensity across locations were influenced by agro-climatic conditions, crop variety, cultural practices, and microclimatic factors. The findings emphasize the need for continuous monitoring and the development of effective, location-specific disease management strategies.