From hills to plains: understanding spatial patterns of wheat foliar blight in Uttarakhand

A field survey was conducted during the rabi seasons of 2023–24 and 2024-25 to assess the distribution and severity of foliar blight in major wheat-growing districts of Uttarakhand. Disease incidence was quantified using the Percent Disease Index (PDI) across multiple locations within Almora, Dehradun, Haridwar, Nainital, and Udham Singh Nagar. The results revealed substantial spatial variability in disease intensity. The highest mean PDI was recorded in Udham Singh Nagar (80.57%), followed by Haridwar (62.23%), indicating highly conducive environmental conditions for pathogen development in the plains and terai regions. Dehradun exhibited moderate severity with an average of approximately 27.06%, whereas the hill districts of Nainital (10.56%) and Almora (7.22%) showed the lowest disease levels. Location-level comparison further highlighted significant within-district variation, with Pantnagar, Jwalapur, and Selaqui identified as high-severity hotspots. The severity gradient from plains to hills reflects the influence of temperature, relative humidity, and cropping systems—particularly the widespread rice–wheat rotation that supports inoculum carryover. The study faced challenges due to differences in climate, terrain, and cropping conditions, as well as the difficulty of carrying out uniform disease assessments across both hill and plain regions. Despite these limitations, the study successfully provided a clear and comprehensive spatial assessment of foliar blight severity across Uttarakhand. Thus, the findings provide important baseline information on disease distribution and identify high-risk zones requiring targeted management interventions. The study highlights the need for developing and promoting region-specific strategies to mitigate foliar blight and enhance wheat productivity in Uttarakhand.