Summary:

Pathogenicity of Phytophthora isolates obtained from water reservoirs and watercourses toward Ligustrum vulgare, Chamaecyparis lawsoniana, Lavandula angustifolia and Rhododendron sp. was evaluated. Tested isolates were detected form 3 water ponds situated in ornamental nurseries, 3 rivers and drainage canal in nursery. All of analysed isolates of P. citrophthora and P. cinnamomi colonized tested plant tissues in the laboratory and greenhouse conditions. There were no dif-ferences in pathogenicity of isolates from host plants in comparison to cultures from different water sources.