Abstract
P. tracheiphila is a conidial fungus causing serious damage and death to the host, particularly lemon [Citrus limon], in Citrus and related genera, in Mediterranean countries and the Black Sea region. So far, however, it is unknown in Spain, Portugal and Morocco, as well as other major citrus-growing regions of the world. This fungus is of concern to many international plant protection organizations and must be prevented from being spread in infected propagative material. It was once reported as seedborne in lemon, but there is no further evidence of this means of transmission. Once in the orchard, the fungus can be carried as spores from pycnidia and from hyphae on the plant and on fallen debris by rain, wind and irrigation water, and perhaps by birds and insects.