Comparison of the potential spread of pinewood nematode (Bursaphelenchus xylophilus) inFinland andIberia simulated with a cellular automaton model

Summary Pinewood nematode ( PWN ) is one of the most threatening invasive pests in the pine forests of E urope, and it has recently spread to the I berian P eninsula via import of timber and wooden packaging material from E ast A sia. A cellular automaton ( CA ) model was developed to simulate and compare the potential spread of PWN by transportation and its vectors, M onochamus beetles in the pine forests of Finland and Iberian Peninsula. The model assumes that all pines are equally sensitive to PWN . The CA is a spatio‐temporal grid‐based model, which can easily be applied on different geographical scales. The effects of climate warming and number of entries from ports on the spread of PWN were studied. A sensitivity analysis was conducted on the most uncertain model parameters. Twenty years after hypothetical entries, the predicted area of symptomatic PWN infection (pine wilt disease, PWD ) was very low in F inland compared to I beria. This was because of the low probability of warm J uly in F inland. The increase in the mean J uly temperature increased the area of PWD ‐infected pine forest relatively more in F inland than in I beria. An increase in the number of entries also increased the area of PWD ‐infected pine forest relatively more in Finland than in Iberia. The probability of PWD infection was the highest in pine forests that were close to entry points and in areas with low elevation and high human population density.