NO FIRE BLIGHT IN SWITZERLAND YET, BUT MEASURES HAVE BEEN TAKEN AGAINST THE DISEASE

Since the last fire blight workshop in Bordeaux in 1983, the fire blight situation has not changed very much in Central Europe (Fig. 1). So far, no fire blight has occurred in Switzerland and the same is true for Austria and Italy.

But the disease is present very near the Swiss border.
Since several years, fire blight was detected and also damages were reported from the south of the Federal Republic of Germany, (near Lake Constance) and from the French region Alsace.
Recently, a new and unexpected case of the disease was found in France, 40 km south of Geneva.
After all, it has to be accepted that a certain introduction of fire blight into Switzerland is only a question of time.
But to keep the disease away from our country as long as possible, phytosanitary measures have been taken since the early seventieth and have been maintained continuously.

There is an import restriction of host plant material because it is strictly forbidden to import any Rosaceous plants, regulated by law.
To obtain new worthy varieties, it is possible to import small numbers of scions through official permission.
However, this plant material must remain in the quarantine station at Wadenswil for a period of two years.

Following the progress of the disease in Western Europe and as a consequence, many nurseries, orchards, public and private parks have been examined intensively for symptoms of fire blight.
Suspected plant material has to be sent to the bacteriology services for detection of Erwinia amylovora.
One service has been developed in Wadenswil, another was recently started in Changins.

As a prediction service for Swiss fruit growers, data from ten automatic weather stations are sent daily to Wadenswil where they are processed by computer for the warning system developed by Billing.
These ten weather stations are set up throughout the country, because the climate in Switzerland is very variable.

Furthermore, an estimate of fire blight risk, developed by Steve Beer is being made in many important orchards.
Results of the combination of the weather and orchard factors concerning fire blight will be available for the local plant protection services and other offices, interested in this problem.

Since 1979, specific Swiss apple and pear varieties are included in a susceptibility test of many varieties in the USA (T. van der Zwet). Based on these results, nurserymen can be advised which

IV International Workshop on Fire Blight

R. Grimm

https://doi.org/10.17660/ActaHortic.1987.217.1