Diversity, distribution and host association of Botryosphaeriaceae species causing oak decline across different forest ecosystems in Algeria

Botryosphaeriaceous fungi associated with holm (Q. ilex) and cork (Q. suber) oak trees exhibiting dieback symptoms and cankers in Algeria, were sampled in twelve regions with different ecological conditions. Based on phylogenetic analyses of ITS and tef1-α loci, 13 species were identified. Three species (Diplodia corticola, Dothiorella iberica and Botryosphaeria dothidea) were found to be common to both oak species, while Doth. sarmentorum, D. mutila, Neofusicoccum vitifusiforme, D. insularis, N. stellenboschiana, Doth. plurivora, D. seriata, D. rosacearum, N. parvum and N. terminaliae were found only on one of the hosts. All the Botryosphaeriaceae taxa inoculated on oak shoots produced brown vascular discolouration, and were shown to be pathogenic on both oak species. Diplodia corticola was the most widespread and frequent species showing the highest aggressiveness towards both hosts. Neofusicoccum stellenboschiana, D. insularis and Doth. plurivora are recorded for the first time on Q. suber and Q. ilex. In addition to altitude, the environmental factors temperature and drought appeared to be influential variables that could describe the occurrence and the geographic distribution of these fungal species.