Modelling rain-splash dispersal of fungal pathogens alongside with canopy structure finding some levers to control disease progression: Cultivar mixture
Résumé
Modelling how fungal spores are dispersed is one of the key parameters to provide relevant information to understand epidemics. When dispersal is at short distance (but still a very effective process) such as rain-splash, interaction with the structure and the architecture of the host canopy (medium of dispersal of the pathogenic agent) become important. Thus, the characteristics of canopy architecture, depending from the choice of cultivar, agronomic practice can be considered to provide alternative disease control methods in order to slow down the dispersal of disease in the field. Based on explicit modelling of the architectural structure of the host plant, and on mechanistic modelling of the rain-splash processes, effects of the canopy structure on spore dispersal will be investigated. The model will be applied to the case study of septoria tritici blotch (STB), caused by Zymoseptoria tritici spread in cultivar mixture. Several resistance levels, proportions, spatial organization, plant architectural traits of the wheat cultivars composing the mixture will be presented. Mechanisms known in cultivar mixtures to slow down the diseases progression such as dilution effect (increase of distance between susceptible plants), barrier effect (physical barrier against pathogen dispersal), escaping (distance increase between susceptible tissue of the same plant) will be characterized.