4: Eco-evolutionary dynamics of pathogens in diversified fields

Diversified cropping systems are more complex than monocrops, yielding interesting emergent properties such as ecosystem services. The use of plant diversity within fields therefore becomes an attractive cropping practice in the context of global changes (e.g. pesticide reduction and climate change). Multiple systems exist, including landraces and heterogeneous cultivated populations, cultivar mixtures, species mixtures, multispecific grassland, agroforestry, crops grown with service plants, etc. Effects can be observed on biotic stress caused by organisms such as bacteria, fungi / oomycetes, viruses, nematodes, etc. These effects of diversified cropping systems in mitigating disease spread and severity could thus contribute to an increase in the ecosystem resilience. Complementary methods have to be used to tackle, understand, quantify and predict this inherent complexity and feedback loops across biological levels (both intra and inter-specific). Experimental approaches are key to characterize / identify mechanisms and assess the performance of such complex systems. These are complemented by modelling approaches which are useful to synthetise scattered knowledge and study the behaviour of these complex systems to identify potential leverages. It is the aim of this symposium to bring together multi-disciplinary expertise from researchers studying pathogen populations in diversified plant communities at the empirical and theoretical levels. We aim to summarise the current understanding of the ecological, evolutionary and physiological mechanisms (inter)acting in diversified cropping systems in order to foster the design of sustainable cropping systems.