Esca is a grapevine disease occurring in all vine-growing areas, including Italy. Multiple fungi that have been associated with esca spread by releasing aerial spores that infect pruning cuts and wounds. The aim of the study was to determine the occurrence of the most common fungi associated with esca in Umbria (central Italy) and to fi nd under what weather conditions they release their spores. Disease incidence was also determined in the summers of 2006 and 2007 on ten grapevine cultivars (Cabernet Sauvignon, Grechetto, Sangiovese, Trebbiano toscano, Pinot bianco, Trebbiano spoletino, Ciliegiolo, Montepulciano, Chardonnay and Merlot) growing together in the same vineyard. Visual inspection of the vines showed that all cultivars were susceptible to esca, but that esca incidence differed in intensity between cultivars. In both years, esca incidence was higher with Cabernet Sauvignon, Sangiovese and Trebbiano toscano, and lower with Montepulciano and Merlot. Disease incidence went up in summer. Phaeomoniella chlamydospora was isolated from vine samples showing dark wood streaking, and Fomitiporia mediterranea from samples with white rot, confi rming that these fungi are involved in esca. Spores of P. chlamydospora were trapped from March to December 2007. Spore release was affected by weather parameters (rain and temperature).