Geographic distribution of fungal endophytes of Quercus sp. in Italy

The geographical distribution of crown endophytic fungi on oaks in Italy is reported, with particular reference to weakness pathogens involved in tree decline, their reciprocal association in different organs and forests and their changes over time. Thousands of isolations were carried out on oak samples from 81 sites all over Italy. The most important and widespread pathogenic endophytes, potentially involved in oak decline, were: Biscogniauxia mediterranea, Cytospora, Colpoma, Coryneum, Discula quercina, Diplodia mutila, Phoma, Phomopsis and Tubakia dryina. Many other endophytes showed antagonistic behaviour: Acremonium, Aureobasidium, Cladosporium, Epicoccum, Gliocladium, Trichoderma, etc. Endophyte association varied with the tree species, with the tissue colonised and rnainly with the type of environment. Some endophytes occurred only in northern Italy (e.g. T. dryina and Coniothyrium), others only in southern Italy (e.g. B. mediterranea, D. mutila, D. quercina), while some occurred in both north and south. Usually endophyte incidence was well related to the severity of the decline degree of the site. The spatial and temporal distribution and associations are discussed.