The aim of this article was to provide an overview on the current status of fruit tree diseases caused by Pseudomonas syringae, their importance and distribution, epidemiology and control possibilities with emphasis on plums and cherry. The plant diseases caused by Pseudomonas syringae are economically important and occur worldwide on large diversity of plants. On stone fruits, diseases caused by different pathovars of Pseudomonas syringae are economically important in major fruit growing regions. The severity of damages and economic importance depends on the geographical region, host plant species and pathovar of P. syringae involved in the disease. Bacterial canker induced by P. syringae pv. syringae on all commercially grown stone fruit species and by pv. morsprunorum predominantly on cherries and plums is considered to be the most serious one. Bacterial decline caused by P. syringae pv. persicae is severe on nectarine and peach. Despite the wide spread and economic importance in the most stone fruit growing areas the diseases caused by Pseudomonas syringae in some areas, e.g. Baltic States, are poorly studied, and the data on distribution and pathovars involved in the diseases observed are still missing.

The choice of rootstock is the main precondition for establishing of high yielding and sustainable plum orchards. Therefore influence of rootstock on the plum cultivars wintering in Latvia climatic conditions becomes more and more actual. Investigation was carried out with the aim to clarify influence of rootstock on the wintering and health status of plum cultivar 'Victoria'. Investigation was carried out at Pure Horticultural Research Centre during two different wintering seasons of 2008/2009 and 2009/2010, in the orchard planted in 2001. The winter of 2008/2009 was characteristic with sharp temperature fluctuations, but winter of 2009/2010 was snowy with stable low temperatures. Sixteen widely used rootstocks known in Europe were included. Plum general tree health status (scored by 1-5 points) and percentage of dead trees were evaluated. No statistically significant differences among rootstocks were established according to the evaluation of tree health status. Differences in wintering ability among rootstocks were stated between two years of investigation. Trees grafted on Brompton seedlings and St. Julien d' Orleans demonstrated the highest winter hardiness (4.3 points). No one dead tree was registered on these two rootstocks. Rootstock GF8/1 was the least suitable for Pure conditions - with general health status scored at 2.3 points after severe winter of 2009/2010, and only 25% of alive trees.