Model-based analysis of spatial heterogeneity: spatial epidemiology of plant diseases in cultivar mixtures

Supervisor

Walter Rossing (FSE Wageningen UR)

Collaboration

Crop and Weed ecology (part of the Centre for Crop Systems of WageningenUR) and Plant Research International of WageningenUR

Introduction

The population dynamics or ‘epidemiology’ of plant diseases is studied to find clues for management. Management may operate at the patch, field or regional level. Cultivar mixtures and intercropping are methods that use genetic variation to reduce disease spread within or between fields. These methods are well known but recent success stories in the pathosystem rice - Magnaporthe grisea and potato - Phytophthora infestans have revived interest of farmers and scientists. Management may influence spatial heterogeneity in various ways, both at the field scale and at the regional scale. The question arises what the consequences are of alternative management interventions for the epidemiology of disease and for crop damage.

Over the last 10 years, new concepts and simulation techniques have been developed that enable us to better study, understand and utilize processes that lead to suppression of disease by cultivar mixtures and intercropping. Work by Van den Bosch demonstrates how disease foci spread in a crop. Spatial simulation techniques such as integro-difference equations may be applied relatively easily using specialized simulation packages such as Matlab. In addition, landscape ecologists have developed concepts such as meta-population dynamics that enable description of species in spatially heterogeneous conditions. In this project you will combine these concepts and tools to evaluate alternative spatial management interventions that reduce disease.

Objectives

  • Evaluation of an existing spatial model for the pathosystem potato - Phytophthora infestans using experimental data
  • Executing scenario studies to establish how disease is affected by alternative patterns of genotypes

Experiences gained

  • Develop a work plan
  • Introduction to literature on the pathosystem potato - Phytophthora infestans
  • Introduction to an existing model on spatial epidemiology of Phytophthora infestans in potato
  • Analysis of experimental data using the model
  • Sensitivity analyses and scenario-studies
  • Write scientific paper and report; colloquium