Abstract

Network models for spread and control of soil-borne fungal plant pathogens

We will review recent developments in the modelling and experimentation of the invasion of fungal plant pathogens in soil. Susceptible sites (hosts) in soil-borne epidemics can be identified as roots or plants in various spatial arrangements, analogous to networks. On these networks, infection of hosts occurs at small scales through mycelial spread between neighbouring sites, yet epidemics are observed at larger scales and involve cascading spread through a population of susceptible sites. The theory of percolation on networks, borrowed from statistical physics, proves to be a powerful framework to scale up from the small to the large scales. In particular, testable hypotheses related to invasion and persistence of epidemics can be formulated. For example, we will show how, using simple artificial experimental systems, it was demonstrated that thresholds for invasion of soil-borne fungal plant pathogens occur, and that these thresholds are consistent with those predicted by percolation theory for phase transitions on networks. We will also discuss how it is possible to analyse the efficiency of specific control strategies for diseases on those networks.