THE BEHAVIOUR OF CERTAIN PEACH TREE CULTIVARS TOWARDS THE ATTACK OF THE MAIN PATHOGEN AGENTS

The purpose of this paper is to highlight the cultivars which are the most resistant to disease and pests and which have adapted the most efficiently to the pedo-climatic conditions of Dobrogea. The research took place during the period 2008-2011 at the RSFG Constanta in a peach tree culture planted in 1991 and it involved the following cultivars: 'Springold', 'Springcrest', 'Cardinal', 'Collins', 'Redhaven', 'Jerseyland' and 'Southland'. Observations were recorded concerning the attack of several fungi (Taphrina deformans, Cytospora cincta, Monilinia laxa and Monilinia fructigena) following the application of phyto-sanitary treatments with insecticides and fungicides administered at the right moment and in optimum quantities. Among the studied pathogens, the blistering of the leaves caused by the Taphrina deformans Berk et Tull. fungus is by far the most damaging foliar pathogen agent. Its attack has serious consequences both upon fruit production as well as upon the physiological balance of the trees, resulting in their degradation. Within the pedo-climatic conditions of the south-eastern part of the country, this disease is quite frequent in cultures which causes severe damage. The majority of the studied cultivars manifested and elevated resistance towards the attack of the Taphrina deformans pathogen. In 2011, the 'Springold' and 'Springcrest' cultivars were sensitive towards this pathogen agent. As far as the latter is concerned, we must mention the fact that the sensitivity of the cultivar is also influenced by the environmental conditions specific to each studied year. The most resistant cultivar (basically, without attack) towards the Cytosphora Cincta is 'Redhaven', while the most sensitive was 'Collins'. As far as the Monilinia laxa and Monilinia fructigena fungi are concerned, all the studied cultivars proved to be tolerant. Following this study, the most valuable genotypes can be extended in demonstrative allotments and commercial plantations.