Modelling the potential spread of Fusarium circinatum, the causal agent of pitch canker in Europe

Key message: Fusarium circinatum is an invasive pathogen causing pitch canker in pine and Douglas fir. This study developed a model for simulating the spread of F. circinatum in Europe. The simulations indicated that the fungus is likely to spread to the pine forests of northern Spain and southwest France.

Abstract: Fusarium circinatum is an invasive forest pathogen causing pitch canker in Europe. It attacks several pine species and Douglas firs. It has already invaded a few places in the Iberian Peninsula and Italy.The aim of this study is to develop a model for simulating the spread of F. circinatum once it enters Europe via various entry points such as harbours, border stations and from nurseries containing tree seedlings. The spread rate was modelled as a function of the spatial distribution of pine and Douglas firs, climatic suitability of different locations to F. circinatum, seedling transportation, insect-mediated transfer from tree to tree, and spread of airborne spores. The fungus is likely to spread to the pine forests of northern Spain (Galicia, Cantabria and Basque Country) and southwest France (Aquitania). There will be some spread towards northern Portugal and southern Italy. Unless there are new arrivals to Central and North Europe, the fungus will not spread to the more northern parts of Europe. Due to the short dispersal distance of spores, F. circinatum cannot easily cross spatial discontinuities in the distribution of host species. F. circinatum is a serious potential invasive forest pathogen in Europe. New admittances of the spores from international trading should be controlled.

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