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RECENT SPREAD AND CURRENT WORLDWIDE DISTRIBUTION OF FIRE BLIGHT.
The disease spread rapidly south and westward across the American continent and north into Canada.
By the mid 1800’s, fire blight reached the Midwestern states of Ohio, Indiana and Illinois, and caused severe injury to apple and pear.
The Great Plains and Rocky Mountains, combined with western air currents slow down the spread of the disease.
Not until the late 1800’s did fire blight reach the western states and caused serious damage in California.
The disease eventually spread into all the fruit-growing provinces of Canada and the northern states of Mexico.
The causal organism, Erwinia amylovora, was not discovered until 1880 at the University of Illinois.
In the early 1900’s, fire blight spread to Japan (1903) and New Zealand (1919) to pear and to Bermuda (1943) on loquat.
Not until after WW II did the disease move long distance eastward from the North American continent to England (1957) and Egypt (1964), from where it spread to numerous countries in Europe and the Middle East.
From England, fire blight spread across the English Channel to hawthorn in the coastal regions France, Belgium and The Netherlands.
Once established, the disease spread easily inland in the wind currents to pear, apple and numerous plants in the family Rosaceae.
Within 20 years, fire blight was present throughout western Europe.
From Egypt, fire blight spread rapidly to Cyprus and Israel, and from there into Turkey, Iran and Greece and into eastern Europe.
Following the creation of independent countries from the former Yugoslavia, the number of countries increased by three (Bosnia, Croatia and Macedonia). Since the last workshop in 1995, new records of fire blight were received from Albania and Spain in late 1995, and Hungary in 1996. In Europe, the only countries that have not reported fire blight to date are: Finland, Liechtenstein, Portugal, Slovakia, Slovenia, and the independent states of the former Soviet Union, including Estonia, Latvia and Lithuania.
Recent microbiological and molecular investigations in New York and West Virginia have shown that the organism causing Bacterial Shoot Blight of Pear, recently reported from Japan, is closely related to the regular fire blight organism.
Reports of fire blight on cotoneaster in the Royal Botanic Garden in Melbourne, Australia were made in 1997, but these observations have never been confirmed.
With these additions, corrections, and explanations the official listing of countries where fire blight has been reported totals 40 entries (Table 1). Unless specified, it should be remembered that all dates mentioned are dates of publication only.