Soilborne diseases caused by Fusarium and Neocosmospora spp. on ornamental plants in Italy

Abstract

During surveys conducted in 2010–2014, several disease symptoms were observed on eight ornamental plant species in different nurseries located in Sicily (Southern Italy). Two Neocosmospora and 31 Fusarium isolates were recovered from symptomatic plants. Fungus identification was based on morphological characteristics and phylogenetic analyses of fragments of the intergenic spacer (IGS), internal transcribed spacer (ITS) and large subunit (LSU) regions of the rDNA; partial fragments of the beta-tubulin (TUB), RNA polymerase largest subunit (RPB1), RNA polymerase second largest subunit (RPB2) and translation elongation factor 1-alpha (EF-1α) genes. The Fusarium species recovered from ornamental plants were F. agapanthi (from Agapanthus africanus), F. anthophilum (Dasylirion longissimum), F. fujikuroi (Trachycarpus princeps), F. oxysporum (Bougainvillea glabra, Cordyline australis ‘Purpurea’, Dasylirion longissimum, Eremophila laanii and Philoteca myoporoides) and F. proliferatum (T. princeps), while N. solani was isolated from crown and root rot of Ficus carica. The pathogenicity of representative isolates collected from each host was tested on seedlings or cuttings grown in a growth chamber. All the Fusarium and Neocosmospora isolates tested were pathogenic and reproduced symptoms identical to those observed in the field, except for F. fujikuroi on T. princeps and F. oxysporum on D. longissimum that were non-pathogenic.