Unravelling spatial dynamics and identification of risk regions associated with grape downy mildew in Karnataka using geostatistical approaches

Abstract

The research focuses on the spatial distribution of grape downy mildew in different vineyards across major districts in Karnataka, India. Covering 6 administrative districts, 14 taluks, and 130 villages, the study employs geostatistical techniques, including GIS, point pattern analysis, and interpolation, to assess the severity and spatial patterns of the disease. Utilizing a 0–9 severity scale, the investigation reveals varying degrees of downy mildew infection in surveyed areas, with potential clusters identified through spatial analysis. District-wise and taluk-specific analyses highlight variations in disease severity, with Doddaballapura exhibiting the highest index at 64.21%, and the lowest at 20.12% in Bagalkot. Agglomerative hierarchical cluster analysis identifies two main clusters among the surveyed districts, providing insights into regional disease patterns. Spatial point pattern analysis, including Local Moran’s I and Ripley’s K function, confirms the presence of clusters and offers a deeper understanding of disease dynamics. Interpolation techniques, such as IDW, reveal inconsistent disease occurrence across locations, emphasizing the need for targeted intervention. Ordinary and indicator kriging provide detailed spatial maps, showing disease severity hot spots in southern Karnataka and select areas in Bijapur district. The study underscores the urgency of addressing the growing threat of grape downy mildew, offering scientifically robust insights for disease management strategies in Karnataka’s diverse grape ecosystems.