Pathogenicity of Phaeoacremonium Species on Grapevines

Several Phaeoacremonium species have been recently described to include some species involved in disease of decline of woody plants and others associated with human infections. Thirteen species are currently reported on grapevines and they are suspected to be involved in Esca and Petri disease. The pathogenic character of new defined species is still unknown and, therefore, pathogenicity studies were conducted in this work. The pathogenicity of the following species was studied on grapevine seedlings and cuttings: Phaeoacremonium aleophilum, P. angustius, P. inflatipes, P. krajdenii, P. mortoniae, P. parasiticum, P. scolyti, P. venezuelense, P. viticola, and Phaeomoniella chlamydospora included as positive control. Two-month-old grapevine seedlings of Vitis vinifera cv. Malvar and cv. Airen were inoculated by watering 10 individual pots with a spore suspension (10(7) spores/ml) of each Phaeoacremonium species. All inoculated seedlings showed typical symptoms of a vascular disease 2 months after inoculation. Grapevine cuttings of Vitis vinifera cv. Monastrell were vacuum-inoculated with a spore suspension (10(8) spores/ml) and individually planted. Plants rated after 5 months showed that all Phaeoacremonium species and P. chlamydospora (used as positive control) caused a significant vascular discoloration, while only Phaeomoniella chlamydospora, Phaoeacremonium mortoniae and P. aleophilum caused a significant root weight reduction compared with a non-inoculated control. Phaoeacremonium parasiticum, P. angustius, P. inflatipes and P. venezuelense caused significant foliar symptoms that included interveinal chlorosis and stunted leaves.