Phaeoacremonium italicum sp. nov., associated with esca of grapevine in southern Italy

To date at least 42 Phaeoacremonium species are known throughout the world. These fungal pathogens are responsible for several syndromes that occur in wood of different hosts, 27 of which have been associated with decline and dieback diseases or esca of grapevine and have been abundantly isolated from necrotic wood of grapevines with Petri and esca disease in vineyards worldwide. During a survey carried out in five vineyards of the grapevine cultivar Italia, several symptomatic samples were collected. A collection of 28 Phaeoacremonium isolates was analyzed. The phylogenetic relationships of the isolates were determined through the study of the β-tubulin and actin gene sequences. Combining morphological, culture and molecular data, three known Phaeoacremonium spp. were found, namely Pm. aleophilum, Pm. parasiticum and Pm. scolyti. One new species is described. Phaeoacremonium italicum can be identified by the common occurrence of bundles of up to 13, conidiophores with up to seven septa, occasionally branched, percurrent rejuvenation and predominantly phialides of type II. This novel species thus is isolated for the first time from grapevine in Apulia (southern Italy).