Modelling strategies for durable deployment of resistance

Control of crop disease, be it by spraying chemicals, by planting resistant varieties, or by any other method, is deployed at the scale of the individual field. However, successful control depends on the management of disease at regional and national scales. How far and how fast a pathogen spreads through a landscape and, indeed, whether or not it persists and for how long, depends upon the topology of susceptible host and how this compares to the typical dispersal scale of pathogens. This details of the interaction changes in both time and space as the susceptible crops are moved around the landscape. Attempting to understand the effect of spatial patterning of host on pathogen dynamics has a long history (van der Plank, 1948), and is still an active area of reseach (Cunniffe et al., 2015). Exploratory work has shown how to adapt the work of DeWoody et al. (2005) to include crop rotation and overwintering in a spatially-structured metapopulation-type model of the agricultural mosaic. A starting point for this project would involve understanding how this can be used to inform strategies for deployment of control. The framework could also be extended, most notably to understand the effects of within-field dynamics, synchronicity in planting and harvesting, and stochasticity in disease spread. Understanding how the landscape structure affects the spread of disease would have a number of applications, feeding into an improved understanding not only of how crop diseases can be controlled effectively, but also of pathogen evolutionary change (e.g. fungicide resistance).