Among continental fruit species sour cherry is in seventh place in the world. Most of the producers are from Russia, Poland, Turkey, Ukraine, United States, Serbia and Hungary. About 70% of the total world production comes from Europe, while Asia has with 20% and finally North America gives remaining 10%. The most common cultivars are Ljubskaja, Vladimirskaja, Ostheim, Schattenmorelle, Újfehértói fürtös, Érdi bőtermő, Montmorency and Oblačinska, while dominant rootstocks are mahaleb and mazzard seedlings (KESEROVIĆ et al., 2014). In Hungary sour cherry breeding has been started 64 years ago. The main goal was to get new self-fertile, disease resistant or tolerant varieties with excellent fruit quality and to extend the harvest period. As results of the Hungarian breeding work 21 sour cherry varieties were registered into the “Hungarian List of Variety” in 2014. (APOSTOL-SZŰGYIS, 2014). Sour cherry (Prunus cerasus L.), has gained growing interest in recent years due to the envisaged health benefits associated with a regular intake of anthocyanins and related polyphenolic compounds (ERCISLI, 2014). Apple (Malus pumila Mill.) is a valuable product both as commercial and also from nutritional points of view. If we compare other fruits, apple has the largest number of varieties. Around 1200 varieties are produced in the whole world (HUNGARIAN FRUIT AND VEGETABLE PRODUCT COUNCIL, 2013). Several methods exist to control, avoid decay and fungal diseases. The most common diseases which causing damage of the commercial and backyard plantings of the sour cherry and apple are brown rot, black knot, and leaf spot. Those diseases do not infect at the same time but they are presented as regular sequences based on the environmental conditions and the development or phrenology of the host. (SHARON, 2003).