First report of Pseudomonas syringae pv. aesculi in Hungary
At the request of the horticultural manager of the Park of the Gödöllő Royal Palace which is located near Budapest, a senior pathologist from the Hungarian NPPO examined several diseased horse chestnut trees at the beginning of May 2013. Some trees displayed a sparse, yellowish, and chlorotic canopy, and a few trees were already dead. Bleeding cankers were also observed at various heights on tree trunks, either still oozing or covered by black and cracked remains of dried exudates. Under the bark, patches of brownish and dying tissues could be observed in the phloem. These symptoms were observed in a row of 98, four-years old trees (Aesculus carnea cv. ‘Briotti’) originating from a nursery in Germany. It is estimated that 40 to 50% of these trees were symptomatic, and it is noted that these symptoms appeared shortly after tree plantation. Samples were collected and tested using biochemical, molecular and biological tests. In June 2013, the presence of Pseudomonas syringae pv. aesculi (EPPO Alert List) was confirmed in diseased trees. The origin of this infection could not be ascertained but it is suspected that the bacterium was introduced with infected planting material. As P. syringae pv. aesculi is not a regulated pest, no official measures were taken. However, the Park management was recommended to destroy and dispose of these horse chestnut trees, as it is expected that within a few years many of them will die anyway. Finally, P. syringae pv. aesculi will be included in the survey programme of amenity trees that is conducted in Hungarian public green areas.
The pest status of Pseudomonas syringae pv. aesculi in Hungary is officially declared as: Present, at one location.
NPPO of Hungary (2013-08).