A Weather-Based Simulation Model for the Development of Wheat Stem Rust Epidemics

Wheat stem rust, a highly destructive wheat disease caused by the fungal pathogen Puccinia graminis f. sp. tritici, has been considered for years to be almost eradicated in Western Europe. However, changes in climatic conditions and appearance of new races, overcoming the previously developed wheat resistances, are fostering its re-emergence. Several outbreaks have already been documented in Europe. The consequences on upcoming wheat productions, due to wind-borne spore dispersal, may be destructive. In this work we present a weather-based infection model for wheat stem rust, developed using laboratory and field data from literature. A warning system, based on the simulation of stem rust infectivity, was also developed to improve field monitoring and help farmers maximize crop protection strategy efficiency. A preliminary validation was performed on actual data not used in model building and pertaining to a wide range of conditions (wheat crops in northern Italy between 2016 and 2020). Satisfactory agreements between simulated and actual data were found.