Survey and Geo-Spatial Distribution of Powdery Mildew in major Cucumber Growing areas of Gilgit, Pakistan

Powdery mildew (Podosphaera xanthii) is a significant threat to cucumbers worldwide. In this study, we examined the prevalence, incidence, and severity of powdery mildew in the major cucumber-growing areas of Gilgit, Pakistan. We conducted surveys across varying altitudes of Hunza, Nagar, and Gilgit regions, encompassing 26 distinct locations. Disease incidence, severity, and prevalence were assessed, and environmental factors such as temperature, humidity, and altitude were also recorded. Spatial distribution analysis was performed with the inverse distance weight (IDW) interpolation method. Isolation and identification of the causal pathogen involved microscopic examination of spores, adhering to mycological keys. The results revealed significant variations in powdery mildew across the surveyed areas. Disease prevalence, disease severity and disease incidence of the three regions ranged from 48 to 80%, 9 to 22%, and 24 to 44%, respectively. Notably, Nomal in the Gilgit region exhibited the highest prevalence (80%) and severity (22%), while Minapin in Nagar showed the lowest prevalence (48%) and incidence (24%). Environmental parameters, particularly temperature and humidity, showed a positive trend with the expression of disease. In conclusion, this research offers crucial insights into the epidemiology of cucumber powdery mildew in the Gilgit region, providing valuable information for developing effective disease management strategies. Keywords: Cucumis sativus L., powdery mildew, disease severity, GIS, IDW, geostatistics, spatial distribution