Charcoal canker is a frequent Quercus suber disease that nowadays contributes to its decline in Portugal. It is caused by Biscogniauxia mediterranea, a wide dispersed endophytic fungus that may be present in symptomless trees, becoming more aggressive in susceptible stressed hosts. This work aims to clarify the fungus dispersal by airborne dispersion and transmission from a tree to its progeny through infected tissues. Thus a Hirst spore-trap and meteorological station were installed in the forest. The results confirmed that ascospores spread as airborne inoculum in natural conditions varying throughout the year. Precipitation is the main factor for ascospores release and wind the way of dispersal. The transmission of the fungus by infected tissues was evaluated in acorns and seedlings from declined and asymptomatic trees, in natural regeneration and in stump sprouting regeneration from infected trees. Although B. mediterranea is present in the seeds, it was not found in seedlings, indicating there is no vertical transmission of the disease. It was also found in natural regeneration in a reduced rate, not due to seed contamination but by early aerial infection. In stump sprouting the fungus was not detected, so it can be used to replace trees.
