Biotic effect of fungal communities inhabiting grapevine phyllosphere on <Emphasis Type="Italic">Phoma negriana</Emphasis>

The effect of 15 fungi species most frequently inhabiting grapevine shoots on the growth of Phoma negriana was examined. Particular species-components of the fungal community were tested in vitro against the pathogen, using the biotic series method. The majority of fungi species inhibited P. negriana growth and the growth of only 3 species from the community, i.e. Alternaria alternata Keiss., Botrytis cinerea Pers. and Phomopsis viticola, was limited by the pathogen. Fungi Trichoderma were found the most effective against P. negriana. They completely degraded the hyphae and conidia of P. negriana after 20–22 days of growth in two-organism cultures. The summary biotic effects of fungal communities from grapevine were generally favourable to the P. negriana growth and only in one year of study they suppressed the pathogen development.