Symptomless survival of Erwinia amylovora on foliage of host plants
In North Ireland (UK), experiments were carried out to study the symptomless survival of Erwinia amylovora (EPPO A2 quarantine pest) on foliar surfaces of host plants. As reported at the 6th International Congress of Plant Pathology in Montreal, the pathogen could be isolated from healthy leaves six months after the bacteria were inoculated onto the foliage and maintained at 90% relative humidity and 19-21ø C in a growth chamber. When E. amylovora was coinoculated on the leaves with Pseudomonas syringae or E. herbicola, two common foliar epiphytes, the E. amylovora persisted and were reduced only slightly. If the leaves, however, developed severe fireblight symptoms the pathogen could not be isolated after 2-3 months. The authors concluded that epiphytic populations of E. amylovora can increase during transportation and that the pathogen can spread on symptomless plants.
Sources
Blakeman, J.P.; McCracken, A.R. (1993) Symptomless survival of Erwinia amylovora (fireblight) on foliar surfaces of host plants.
Presentation at the 6th International Congress of Plant Pathology, Montreal, CA, 1993-07/08-27/06.