Low-density barriers for controlling plant crowd diseases: How far and fast can pathogens spread?

We explore numerically the possibility of controlling the spread of plant diseases characterized by relatively low dispersal (crowd diseases) through the introduction of a spatial barrier with low density of susceptible hosts. We use the diffusion approximation to Kendall's spatially extended version of the Kermack–McKendrick epidemic model and illustrate our findings within the context of a representative viral disease that affects cocoa trees. RECOMMENDATIONS FOR MANAGERS:. Our numerical results suggest that using low-density barriers of hosts in crowd plant diseases might be an effective way of halting the spatial dispersal of pathogens. The introduction of these barriers may reduce the economic impact when compared with other methods of controlling the disease spread. Before using the model to approximate suitable sizes of barriers, it is necessary to execute an exhaustive assessment of the model appropriateness for any particular disease under consideration. Our results suggest that to improve the efficiency of low-density barriers it is important to explore their use in combination of current alternative control methods.