Relative importance of olive orchards as spreaders of Xylella fastidiosa in Puglia. Colors show the probability (averaged over 1000 simulations and rescaled between 0 and 1) of an orchard becoming infected with X. fastidiosa in simulations of the bacterium becoming endemic in the Puglia region. Dark grey areas are other land cover types in Puglia, while light grey areas were not analyzed. The magenta line delineates the current buffer zone that is intensely monitored and aims to prevent X. fastidiosa from spreading north. The map was generated using the Python Basemap Matplotlib Toolkit (http://matplotlib.org/basemap/).