Modelling and mapping potential epidemics of wheat diseases—examples on leaf rust and Septoria tritici blotch using EPIWHEAT

Abstract

Policy makers and researchers need to develop long-term priorities using reliable, quantitative tools to assess the risks associated with plant diseases over a range of plant pathogens and over space. EPIWHEAT is a generic simulation model designed to analyse potential disease epidemics in wheat, i.e., epidemics that depend only on the physical environment, and that are not constrained by any disease control. The model is developed on a core structure involving healthy, latent, infectious, and removed sites, and accounts for lesion expansion. It simulates in a simple way host dynamics (growth and senescence). The model involves as few parameters as possible, and a few driving functions. Here, EPIWHEAT is populated with parameters for brown rust (leaf rust; Puccinia triticina) and Septoria tritici blotch (Zymoseptoria tritici). Simulated epidemics are compared to observations at the field, national (France), and European scales. The model appears to represent a sound basis for predicting potential epidemics of wheat foliar diseases at large scales. Areas for model development are documented and discussed. EPIWHEAT appears to provide a simple, generic, transparent, flexible, and reliable platform to modelling potential epidemics caused by leaf pathogens of wheat.