According to Kraj, W., Zarek, M. & Kowalski, T. (2012) there are several strains of C. fraxinea in Poland.

As has been widely reported, ash dieback is now established in Lithuania, Latvia, Estonia, Baltic Russia (Kaliningrad), Finland, Sweden, Denmark and Germany, as well as Poland and these are all countries with a Baltic shore. The fungus is also now widespread in southern Norway, just outside the Baltic.

In the south the disease has advanced steadily across central Europe as far as France, Italy, Romania and other countries.

The terrestrial route seems consistent with propagation mainly by airborne spores of the H. pseudoalbidus stage and maps produced in France illustrate this well.  In following the advance of C. fraxinea, it is important to try and discover the first reports in different areas as (a) the fungus spreads very rapidly and (b) once discovered far more people start looking for it. Also it has to be borne in mind that it may have been present for some years before being detected. Because of this and other factors, possible dispersal routes become unclear quickly.

The terrestrial route seems consistent with propagation mainly by airborne spores of the H. pseudoalbidus stage and maps produced in France illustrate this well.  In following the advance of C. fraxinea, it is important to try and discover the first reports in different areas as (a) the fungus spreads very rapidly and (b) once discovered far more people start looking for it. Also it has to be borne in mind that it may have been present for some years before being detected. Because of this and other factors, possible dispersal routes become unclear quickly.

increasingly suggestions are being made that the pathogen has been present in Britain and elsewhere since well before its first report and, if this is correct, at least some nursery stock may have been infected from local woodlands after importation.

So far as the British Isles is concerned, virtually all the current records of Chalara from the wider environment (i.e. not from nurseries or recent plantings) are on the eastern side of the country, many close to the coast. While wind borne spores from mainland Europe may be responsible for many of these outbreaks, most are also near ports, places where there are many arrivals and departures of people and goods to and from other countries. This is particularly apparent in the area around Dover and Folkestone (Forestry Commission, 2012).

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