T. Hasler, H.J. Schaerer, E. Holliger, J. Vogelsanger, A. Vignutelli, B. Schoch
In 1989 the first incidence of fire blight was observed in Switzerland. Until 1994 only 2 to 5 communities were involved. In the years 1995/1996 the disease spread slowly resulting in fire blight in 38 communities.
From 1997 to 2000 a massive spread of fire blight was noted: In the years 1997/1998 a further increase was recorded with 170 communities involved and the very exceptional increase in the year 2000 doubled the involved communities to 365. In this year the western part of the country was attacked for the first time.
Fire blight is now established all over Switzerland. The disease is now present in all apple and pear production areas, with the exception of canton Wallis.
During the bloom period in spring only 1 to 3 days of infection were predicted using “MARYBLYT” in the main production areas due to the rainy and cool conditions. These conditions are partly responsible for fire blight not spreading in the first year of occurrence. But 2000 was a very difficult year with exceptionally warm conditions during bloom. In several regions 8 to 10 days of infection were recorded and at least 10 additional days with high risk, when just rain or dew were absent. This high infection potential caused extraordinary damage and losses in both orchards and high solitary trees. In the two hot spots (eastern and central Switzerland) about 50 ha of orchards were completely eradicated and more than 8000 high solitary trees scattered in the landscape where rooted out. Altogether several hundred hectares were attacked and had to be cut back to reduce infestation. For the eradication program in 2000 official authorities (federal and cantonal government, each 50%) paid nearly 5 Mill. Swiss francs (>2 Mill. US$). The costs for all the eradication and control programs in the years 1989 to 2000 (including the preventive eradication of Cotoneaster salicifolius) amounted to 12 Mill. Swiss francs (9 Mill. US$)
Hasler, T., Schaerer, H.J., Holliger, E., Vogelsanger, J., Vignutelli, A. and Schoch, B. (2002). FIRE BLIGHT SITUATION IN SWITZERLAND. Acta Hortic. 590, 73-79
DOI: 10.17660/ActaHortic.2002.590.8

Acta Horticulturae