Modeling the ecological niche of Verticillium dahliae in southern Spain: Current patterns and projected shifts under climate change

Verticillium wilt, caused by the soil-borne plant pathogenic fungus Verticillium dahliae, poses a major threat to agriculture, affecting over 400 plant species globally. This study aims to characterize environmental correlates of the occurrence of V. dahliae infections in Andalusia, southern Spain, and to estimate its current and future potential distribution. Data derived from 15 years of active monitoring of Verticillium wilt in olive and cotton were analyzed using two complementary modeling approaches including general linear models using presence/absence records to model occurrence probability, and maximum entropy modeling using presence/background records to explore environmental suitability. Temperature and precipitation variables were key factors in the models, while soil texture and landscape features (i.e., slope and solar radiation) contributed to a lesser extent. Projections of suitability to landscapes in southern Spain under future climate scenarios anticipate a shift in suitable areas towards the southern and southeastern parts of Andalusia, driven by rising temperatures and changing precipitation patterns. None of the models projected a decrease in suitability for the pathogen in the region. These findings provide valuable insights for Integrated Disease Management (IDM) strategies, emphasizing the importance of avoidance and exclusion of the pathogen using pathogen-free certified planting material and selecting locations to establish new plantations based on soil phytosanitary status and pathogen risk. Our results underscore the utility of ecological niche models to predict disease occurrence and spread.