The diversity of Botryosphaeriaceae species associated with “Botryosphaeria dieback” of grapevine was investigated in 18 vineyards in Sardinia, Italy. Lasiodiplodia isolates obtained from different woody hosts including holm oak, sweet orange and broom bush in Italy, Algeria and Tunisia were also characterized. Morphological and cultural characteristics as well as ITS and EF1-α sequence data were used to identify the fungal isolates. Forty-eight botryosphaeriaceous isolates were obtained from 113 symptomatic grapevine samples, from which ten species were identified. Diplodia seriata was the dominant species (25 % of isolates), followed by Neofusicoccum parvum (21.7 %). Two species, Diplodia olivarum and D. africana are reported for the first time on grapevine. In addition, two new species namely Lasiodiplodia mediterranea sp. nov. from grapevine, holm oak and sweet orange and Lasiodiplodia exigua sp. nov. from broom bush are described. In artificial inoculation experiments conducted on excised green grapevine shoots and lignified canes as well as holm oak seedlings, L. mediterranea was shown to be an aggressive pathogen.

Cork oak (Quercus suber) forests are economically and culturally intertwined with the inhabitants of the Mediterranean basin and characterize its rural landscape. These forests cover over two million hectares in the western Mediterranean basin and sustain a rich biodiversity of endemisms as well as representing an important source of income derived from cork production. Currently cork oak forests are threatened by several factors including human-mediated disturbances such as poor or inappropriate management practices, adverse environmental conditions (irregular water regime with prolonged drought periods), and attacks of pathogens and pests. All these adverse factors can interact, causing a complex disease commonly known as “oak decline.” Despite the numerous investigations carried out so far, decline continues to be the main pathological problem of cork oak forests because of its complex etiology and the resulting difficulties in defining suitable control strategies. An overview of the literature indicates that several pathogenic fungi and oomycota can play a primary role in the etiology of this syndrome. Therefore, the aim of this review is to analyze the recent advances achieved regarding the bio-ecology of the endemic and emerging pathogens that threaten cork oak trees with particular emphasis on the species more directly involved in oak decline. Moreover, the effect of climate change on the host-pathogen interactions, a task fundamental for making useful decisions and managing cork oak forests properly, is considered.

The Mediterranean basin is recognized as a global biodiversity hotspot accounting for more than 25,000 plant species that represent almost 10% of the world’s vascular flora. In particular, the maquis vegetation on Mediterranean islands and archipelagos constitutes an important resource of the Mediterranean plant diversity due to its high rate of endemism. Since 2009, a severe and widespread dieback and mortality of Quercus ilex trees and several other plant species of the Mediterranean maquis has been observed in the National Park of La Maddalena archipelago (northeast Sardinia, Italy). Infected plants showed severe decline symptoms and a significant reduction of natural regeneration. First studies revealed the involvement of the highly invasive wide-host range pathogen Phytophthora cinnamomi and several fungal pathogens. Subsequent detailed research led to a better understanding of these epidemics showing that multiple Phytophthora spp. were involved, some of them unknown to science. In total, nine Phytophthora species were isolated from rhizosphere soil samples collected from around symptomatic trees and shrubs including Asparagus albus, Cistus sp., Juniperus phoenicea, J. oxycedrus, Pistacia lentiscus and Rhamnus alaternus. Based on morphological characters, growth-temperature relations and sequence analysis of the ITS and cox1 gene regions, the isolates were identified as Phytophthora asparagi, P. bilorbang, P. cinnamomi, P. cryptogea, P. gonapodyides, P. melonis, P. syringae and two new Clade 6 taxa which are here described as P. crassamura sp. nov. and P. ornamentata sp. nov. Pathogenicity tests supported their possible involvement in the severe decline that is currently threatening the Mediterranean maquis vegetation in the La Maddalena archipelago.

Studies on the taxonomy and phylogeny of Diplodia have been hampered by the lack of an ex-type culture linked to the holotype of D. mutila, which is the type of the genus. In this study a large collection of Diplodia strains, obtained from ash and other woody hosts showing V-shaped cankers and branch dieback, were identified based on morphological characters and DNA sequence data from ITS and EF1-α loci. Results of combined morphological and phylogenetic analyses showed that the Fraxinus isolates from Italy, the Netherlands, Portugal and Spain belong to three distinct species namely Diplodia fraxini, Diplodia mutila and Diplodia subglobosa sp. nov. An epitype was designated for Diplodia mutila, with associated ex-epitype cultures. The name D. fraxini is re-instated and a neotype designated. Two species, Diplodia seriata and Diplodia pseudoseriata were reported for the first time on Fraxinus spp.