PCR-RAPD was used to explore the genetic variability in Phellinus (Fomitiporia) sp. isolates from escaaffected
vines. The use of 20 random primers yielded 180 polymorphic markers. Cluster-analysis grouped isolates by
their origin, geographical location and host plant, but not by their tentative identification as Phellinus sp. or F.
punctata. This shows that all isolates tested belonged to a single species, probably F. punctata. Observations carried
out on samples of isolates representative of the population of Phellinus sp. present in each of two vineyards indicated
that clonal plant-to-plant propagation of the fungus did not occur and that infections were probably caused
by basidiospores. RAPD markers common to all tested isolates of Phellinus sp. (F. punctata), but never observed
with other grape-associated fungi, were identified and are now being exploited to set up diagnostic techniques
based on PCR or molecular probes