Sour cherries become more popular due to their food value. Therefore sour cherries could be a profitable crop for fruit growers in Latvia. Information about sour cherry response to soil moisture adjustment is needed, because based on previous studies it is not possible to predict the influence of irrigation and mulch on sour cherry growing. The trial was carried out at the Latvia State Institute of Fruit Growing in 2007 to determine the effect of soil moisture adjustment on the growth of different sour cherry cultivars. Woodchip mulch and drip irrigation were used as main factors, cultivars 'Bulatnikovskaya', 'Desertnaya Morozovoi', 'Latvijas Zemais', 'Orlica', 'Shokoladnica', 'Tamaris', 'Zentenes' were used as a secondary factor. Vegetative growth, branching angles of lateral shoots, proportions of pruned shoots, spurs and twigs were determined to characterize the response of cultivars to mulching and irrigation. In general use of drip irrigation increased vegetative growth of sour cherries, but the use of woodchip mulch decreased this growth. Branching angles were wider in variant with woodchip mulch. Cultivar 'Zentenes' most positively responded to use of woodchip mulch and drip irrigation.

Precocity of fruit plants enables early obtaining of yield and income. But precocity can be influenced by drought. In some cases precocity is related to insufficient growth and insufficient yield in the succeeding years. The precocity of sour cherries was investigated in the trial established at the Latvia State Institute of Fruit Growing. Soil moisture treatments - woodchip mulch and drip irrigation as well as cultivars ‘Bulatnikovskaya’, ‘Desertnaya Morozovoi’, ‘Latvijas Zemais’, ‘Orlica’, ‘Shokoladnica’, ‘Tamaris’, and ‘Zentenes’ were used as trial factors. The flowering and yielding was observed in 2008 and 2009. Flowering, fruit set, fruit mass, and yield were characterized in order to evaluate precocity of cherries in different soil moisture treatment variants. The use of drip irrigation did not influence the yield of sour cherries, but the use of woodchip mulch decreased the yield in the third growing year. The cultivar ‘Tamaris’ was the most precocious, and the cultivar ‘Bulatnikovskaya’ was the most productive.

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 contents of soluble solids, acids and their ratio as well as phenol content are important indices for quality evaluating of sour cherry fruits. These parameters are influenced by the cultivar and growing conditions. The trial was carried out at the Latvian State Institute of Fruit-Growing to evaluate the effect of woodchip mulch and drip irrigation on fruit quality of sour cherry cultivars 'Bulatnikovskaya', 'Desertnaya Morozovoi', 'Latvijas Zemais', 'Orlica', 'Shokoladnica', 'Tamaris', and 'Zentenes'. The biochemical composition of the fruits was analyzed in 2009 and 2010. The content of soluble solids was determined with the method of refractometry; the content of total acids by titrating with 0.1N NaOH; the total content of phenols with the method of spectrometry. The content of total soluble solids in sour cherry fruits was decreased by use of woodchip mulch. The content of acids, the ratio of soluble solid content to the acid content and the content of the phenols was not significantly influenced by woodchip mulch and drip irrigation. The cultivar 'Desertnaya Morozovoi' showed the highest soluble solid content in the fruits, the cultivar 'Latvijas Zemais' - the highest acid content, and cultivar 'Tamaris' - the highest phenol content in the fruits.