Overview on wood decay fungi of ornamental broadleaves and conifers in the city of Genoa

In the Autumn of 2010, a total of 1353 broadleaves and 165 conifers from 76 urban sites in the city of Genoa (Liguria, Italy) were inspected for the presence of fruiting bodies of wood decay fungi. Fungal identifications were performed either through traditional techniques or DNA sequencing. In addition, conifers were sampled at the root collar through a drill-based technique; wood samples were analyzed by using a recently developed multiplex-PCR approach for the detection of wood decay fungi commonly associated with conifers. Tree species included: Cedrus spp., Celtis australis, Citrus xaurantium, Cupressus spp., Pinus spp., Platanus spp., Quercus ilex, Sophora japonica and Taxus spp. 12% of broadleaves displayed fungal fruiting bodies. Fomitiporia punctata, Ganoderma resinaceum, Inonotus hispidus and Perenniporia fraxinea were the most frequent fungal species. Only I. hispidus displayed strict host preference (97% of fruiting bodies observed on S. japonica). 2% of conifers displayed fruiting bodies of either Fuscoporia torulosa or Phaeolus schweinitzii. Based on results of multiplex-PCRs, 16% of trees were found to be infected by at least one taxon detectable through this molecular diagnostic approach, which allowed to detect Armillaria spp., Fomitopsis pinicola and Porodaedalea spp. in addition to the above fungi. This finding suggest that diagnosis based on visual inspection overlooks more than 85% of wood decay affected trees.