Horse Chestnut Bleeding Canker Caused by Pseudomonas syringae pv. aesculi in the Czech Republic

In 2002-2003 the upsurge of horse chestnut bleeding canker was recorded in some states of western Europe and thousands of trees were reported to be affected. Phytophtora species were suspected as causal agents but were not detected and a new bacterial pathogen, Pseudomonas syringae pathovar aesculi, was proven to be associated with this massive disease incidence in Europe. In the Czech Republic a partial survey of bleeding canker symptoms was conducted since 2003 but only untypical symptoms of oozing were sporadically found. The first typical symptoms were found in 2006 and till 2011 more than 3000 on more than 200 localities were inspected. The typical symptoms were found on 18 localities all over the Czech Republic. For laboratory analysis 3 localities with many trees showing the symptoms and 6 localities with a few trees showing severe symptoms were chosen. P. syringae was identified on three localities, two of which have already been identified as the Pseudomonas syringae pathovar aesculi. On one locality Phytophtora cactorum was identified on one three with very intensive bleeding. There were no co-infections of the bacterium and Phytophtora found on any locality