MONITORING OF EPIPHYTIC POPULATIONS OF ERWINIA AMYLOVORA IN THE NETHERLANDS

The possibility that sudden outbreaks of fireblight may result from the presence of epiphytic populations of Erwinia amylovora has been investigated in The Netherlands.
With the use of a monitoring system developed in California, trials were carried out in 1974 and 1975 on Cotoneaster salicifolius cv. ‘Avondrood’, Pyrus communis (pear) and Crataegus monogyna (hawthorn). Epiphytic populations of E. amylovora were generally found only after the occurrence of fireblight infections in the close proximity of the experimental areas.
These observations appear to coincide with similar observations made in Michigan and in Ontario (Can.) but contrast with those made in California.
No significant build up of epiphytic E. amylovora could be demonstrated, as apposed to a gradual build up in California where monitoring has proved to be successful.
It must be concluded that under our climatic conditions, the monitoring technique shows little promise as a warning system for the control of fireblight in The Netherlands.

Symposium on Fire Blight

H.J. Miller, H. van Diepen

https://doi.org/10.17660/ActaHortic.1978.86.9