EPIDEMIOLOGICAL SURVEY OF THE FIRE BLIGHT DEVELOPMENT IN BELGIUM (1971–1985)

For fifteen years, Erwinia amylovora has become endemic in all parts of the country where nurseries and orchards are of economic importance.
In order to evaluate the actual situation of this bacteriosis, the general trends in the extension of fire blight have been studied, comparing meteorological data and the symptomatological records available.
The period 1971–1978 was less dangerous than the following years on the basis of the Billing’s potential doubllings.
The potentially most prone years for outbreaks seem to have been 1971 (if fire blight had already been present in Belgium), 1975, 1981, 1982 and 1985. This last season was in fact the worst one.

Since 1980 detailed records collected by several research centres from Durondeau pear orchards reveal that the symptom’s peaks can be to some extent related with maximal temperatures and rainfall, but that discrepancies often arise, because other epidemiological factors overshadow the effect of weather.
Therefore, research has been carried out in 1985 in order to make the host influence clear.
A general review of blooming dates since 1971 confirms the low infection risks of first bloom of pears contrary to hawthorns flowering.
Prelliminary results from a study about other phenological characteristics show a direct relationship between various stages of plant phenology (as shoot length or secondary flowering) and symptoms’ appearnce.

IV International Workshop on Fire Blight

Y. Timmermans, M. Laroche

https://doi.org/10.17660/ActaHortic.1987.217.19