Studio sulle specie diPhytophthorapresenti in ambienti forestali della Sardegna

Phytophthoraspp. are devastating plant pathogens in both agricultural and natural environments. Since little is known about the occurrence and spread ofPhytophthoraspp. in Sardinia, a survey was carried out in various forest ecosystems. Overall two chestnut groves, one oak stand, two riparian ecosystems and three forest nurseries were surveyed. Isolations were made directly from symptomatic plant tissues and usingRhododendronleaves and apples as bait. Molecular and morphological characterizations were used to identify the isolates. Aggressiveness of thePhytophthoraisolates was assayed by different methods: soil infestation and stem inoculation of seedlings and by inoculating living logs. It was also evaluated the ability of some species to producein vitrophytotoxic metabolites. The survey revealed the presence of 12 species ofPhytophthora:P. cambivora, P. cinnamomi, P. cinnamomi var. parvispora, P. cryptogea, P. gonapodyides, P. ilicis, P. nicotianae, P. pseudosyryngae, P. taxon niederhauserii, P. taxon salixsoil, Phytophthorasp. 1 ePhytophthorasp. 2. In particular:P. cinnamomivar.parvispora,P. pseudosyringaeandP. taxon niederhauseriiwere recorded in a new association host-pathogen in Italy. Another species,P. ilcisis here reported for the first time in a natural ecosystem in the Mediterranean basin.