Effects of Fungicide Treatments for the Control of Epidemic and Exotic Calonectria Diseases in Italy

The efficacy of 11 fungicides was evaluated for the control of Calonectria infections on bottlebrush (Callistemon "Masotti") and feijoa (Acca sellowiana), with special emphasis on Calonectria pauciramosa and C. morganii, which are the most destructive species in Italian ornamental nurseries. Three nursery experiments were performed with the selected fungicides in order to determine their ability to prevent leaf spot caused by C. morganii on bottlebrush and leaf spot and crown and root rot caused by C. pauciramosa on bottlebrush and feijoa. All fungicides were effective in reducing disease infections, except for cyproconazole, propamocarb + fosetyl-Al, and K phosphite that were the least effective in reducing C. morganii leaf spot. In contrast, K phosphite proved more effective in reducing crown and root rot caused by C. pauciramosa. Fungicides were also evaluated in growth-cabinet experiments for their ability to reduce incidence and severity of leaf spot on bottlebrush caused by the exotic pathogens C. pseudomexicana, C. tunisiana, C. polizzii, and C. mexicana. Copper hydroxide, fosetyl-Al, prochloraz, prochloraz + cyproconazole, and tebuconazole were always effective in reducing Calonectria leaf spot on bottlebrush. However, some differences in levels of control might be attributable to Calonectria isolate. Overall, this study clearly indicates that new fungicides can be employed for chemical management of Calonectria infections in ornamental nurseries

Update of pistachio leaf spot caused by Septoria pistaciarum in light of new taxonomic advances in Italy.

Abstract Septoria leaf spot is one the most widespread disease affecting pistachio (Pistacia vera) in countries of the Mediterranean region. Traditionally, three species have been associated with pistachio, including Septoria pistaciae, Septoria pistaciarum and S. pistacina. However, recent taxonomic studies have reordered and clarified the status of Septoria and septoria-like pathogens affecting pistachio. In our study, field surveys conducted in the traditional Sicilian pistachio production area of Bronte revealed the presence of trees showing characteristic septoria-like leaf spot. Collected isolates were morphologically and molecularly characterized. Morphological characterization was based on conidia measurements and evaluation of mycelial growth on different artificial media. Tested media included CMA, MEA, OA, PDA, and SNA. Phylogenetic analysis was conducted on a multi-locus approach (ITS + tef1 + tub2) based on Maximum Parsimony and Maximum Likelihood. Results showed that our isolates clustered with S. pistaciarum. Pathogenicity test was conducted in the field using conidia suspensions in order to fulfill Koch's postulates. Presence of characteristic rounded spots and pycnidia was evaluated on the inoculated leaves 9 and 23 days after inoculation. This study represents the first update on S. pistaciarum in Italy since its first identification in 1934

Cylindrocladiella peruviana and Pleiocarpon algeriense causing stem and crown rot on avocado (Persea americana)

AbstractDuring the winter of 2018, 3-years-old trees of avocado (Persea americana) cv "Hass" from Trapani province (Sicily, Italy) showed symptoms of stem and crown rot. Two different fungi were consistently isolated from infected tissues. Morphological characterization and multi-locus phylogenies using five genomic loci (ITS, tef1, tub2, his3, and rpb2) identified these fungi as Cylindrocladiella peruviana and Pleiocarpon algeriense. Pathogenicity tests on healthy 5-months-old seedlings and 3-year-old trees of avocado reproduced similar symptoms as those observed in nature, and Koch's postulates were fulfilled for both pathogens. Moreover, the tested fungal isolates revealed a different pathogenic behaviour among two species. Two isolates of Pleiocarpon algeriense resulted more aggressive than Cylindrocladiella peruviana isolates causing major lesions on young seedlings. This study is the first to report of stem and crown rot on avocado caused by Cylindrocladiella peruviana and Pleiocarpon algeriense

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

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

Characterisation and mefenoxam sensitivity of Phytophthora spp. from ornamental plants in Italian nurseries

Genetic variability and mefenoxam sensitivity are described for Phytophthora spp. isolates recovered from nine ornamental plant species at four locations in Sicily, Southern Italy. Fifty-four isolates of Phytophthora spp. were obtained from symptomatic plant tissues. Mating type analyses revealed that all isolates are heterothallic, consisting of mating type A1. Fungicide sensitivity assays determined that all isolates are sensitive to mefenoxam. Characterisation of 48 isolates was performed using molecular and phylogenetic analyses of the internal transcribed spacer of ribosomal DNA (rDNA-ITS), beta-tubulin (β-tub) and elongation factor 1 alpha (EF-1α) regions. The isolates belonged to Phytophthora nicotianae (34 isolates), P. arecae (syn. palmivora) (five) and P. niederhauserii (nine). The pathogenicity of three representative isolates was tested on seedlings or cuttings of each host, grown in a growth chamber. All isolates were pathogenic and reproduced symptoms identical to those observed in the nursery. This is the first report of disease caused by P. nicotianae, P. arecae or P. niederhauserii on several ornamental plants in Italy, and of the sensitivity of these Phytophthora species to mefenoxam

Silver doping of silica-hafnia waveguides containing Tb3+/Yb3+ rare earths for downconversion in PV solar cells

The aim of this paper is to study the possibility to obtain an efficient downconverting waveguide which combines the quantum cutting properties of Tb3+/Yb3+ codoped materials with the optical sensitizing effects provided by silver doping. The preparation of 70SiO(2)-30HfO(2) glass and glass-ceramic waveguides by sol-gel route, followed by Ag doping by immersion in molten salt bath is reported. The films were subsequently annealed in air to induce the migration and/or aggregation of the metal ions. Results of compositional and optical characterization are given, providing evidence for the successful introduction of Ag in the films, while the photoluminescence emission is strongly dependent on the annealing conditions. These films could find potential applications as downshifting layers to increase the efficiency of PV solar cells. (C) 2016 Elsevier B.V. All rights reserved

Fusarium and allied fusarioid taxa (FUSA). 1

Seven Fusarium species complexes are treated, namely F. aywerte species complex (FASC) (two species), F. buharicum species complex (FBSC) (five species), F. burgessii species complex (FBURSC) (three species), F. camptoceras species complex (FCAMSC) (three species), F. chlamydosporum species complex (FCSC) (eight species), F. citricola species complex (FCCSC) (five species) and the F. concolor species complex (FCOSC) (four species). New species include Fusicolla elongata from soil (Zimbabwe), and Neocosmospora geoasparagicola from soil associated with Asparagus officinalis (Netherlands). New combinations include Neocosmospora akasia, N. awan, N. drepaniformis, N. duplosperma, N. geoasparagicola, N. mekan, N. papillata, N. variasi and N. warna. Newly validated taxa include Longinectria gen. nov., L. lagenoides, L. verticilliforme, Fusicolla gigas and Fusicolla guangxiensis. Furthermore, Fusarium rosicola is reduced to synonymy under N. brevis. Finally, the genome assemblies of Fusarium secorum (CBS 175.32), Microcera coccophila (CBS 310.34), Rectifusarium robinianum (CBS 430.91), Rugonectria rugulosa (CBS 126565), and Thelonectria blattea (CBS 952.68) are also announced her

Fusarium: more than a node or a foot-shaped basal cell

Recent publications have argued that there are potentially serious consequences for researchers in recognising distinct genera in the terminal fusarioid clade of the family Nectriaceae. Thus, an alternate hypothesis, namely a very broad concept of the genus Fusarium was proposed. In doing so, however, a significant body of data that supports distinct genera in Nectriaceae based on morphology, biology, and phylogeny is disregarded. A DNA phylogeny based on 19 orthologous protein-coding genes was presented to support a very broad concept of Fusarium at the F1 node in Nectriaceae. Here, we demonstrate that re-analyses of this dataset show that all 19 genes support the F3 node that represents Fusarium sensu stricto as defined by F. sambucinum (sexual morph synonym Gibberella pulicaris). The backbone of the phylogeny is resolved by the concatenated alignment, but only six of the 19 genes fully support the F1 node, representing the broad circumscription of Fusarium. Furthermore, a re-analysis of the concatenated dataset revealed alternate topologies in different phylogenetic algorithms, highlighting the deep divergence and unresolved placement of various Nectriaceae lineages proposed as members of Fusarium. Species of Fusarium s. str. are characterised by Gibberella sexual morphs, asexual morphs with thin- or thick-walled macroconidia that have variously shaped apical and basal cells, and trichothecene mycotoxin production, which separates them from other fusarioid genera. Here we show that the Wollenweber concept of Fusarium presently accounts for 20 segregate genera with clear-cut synapomorphic traits, and that fusarioid macroconidia represent a character that has been gained or lost multiple times throughout Nectriaceae. Thus, the very broad circumscription of Fusarium is blurry and without apparent synapomorphies, and does not include all genera with fusarium-like macroconidia, which are spread throughout Nectriaceae (e.g., Cosmosporella, Macroconia, Microcera). In this study four new genera are introduced, along with 18 new species and 16 new combinations. These names convey information about relationships, morphology, and ecological preference that would otherwise be lost in a broader definition of Fusarium. To assist users to correctly identify fusarioid genera and species, we introduce a new online identification database, Fusarioid-ID, accessible at www.fusarium.org. The database comprises partial sequences from multiple genes commonly used to identify fusarioid taxa (act1, CaM, his3, rpb1, rpb2, tef1, tub2, ITS, and LSU). In this paper, we also present a nomenclator of names that have been introduced in Fusarium up to January 2021 as well as their current status, types, and diagnostic DNA barcode data. In this study, researchers from 46 countries, representing taxonomists, plant pathologists, medical mycologists, quarantine officials, regulatory agencies, and students, strongly support the application and use of a more precisely delimited Fusarium (= Gibberella) concept to accommodate taxa from the robust monophyletic node F3 on the basis of a well-defined and unique combination of morphological and biochemical features. This F3 node includes, among others, species of the F. fujikuroi, F. incarnatum-equiseti, F. oxysporum, and F. sambucinum species complexes, but not species of Bisifusarium [F. dimerum species complex (SC)], Cyanonectria (F. buxicola SC), Geejayessia (F. staphyleae SC), Neocosmospora (F. solani SC) or Rectifusarium (F. ventricosum SC). The present study represents the first step to generating a new online monograph of Fusarium and allied fusarioid genera (www.fusarium.org)

Integrated Management for the Reduction of Calonectria Infections in Ornamental Nurseries.

Chemical control represents the main effective strategy for managing Calonectria diseases in ornamental nurseries. The occurrence of fungicide-resistant strains and the European Directive on "Sustainable Use of Pesticides" has forced ornamental plant growers to establish effective integrated pest management strategies to control Calonectria infections. Here, three nursery experiments were performed to detect the best combinations of fungicides and biological control agents (BCA) to control both leaf spot, caused by six Calonectria spp. on bottlebrush and metrosideros, and stem rot, caused by Calonectria morganii on Dodonaea plants. Overall, the cyprodinil + fludioxonil mixture alone or combined with bioformulates containing Bacillus, Trichoderma, and Streptomyces spp. provided the best performance in reducing leaf spot and stem rot caused by Calonectria spp., followed by the mixture of boscalid + pyraclostrobin. Although BCA alone provided disease suppression significantly lower than the controls in most cases, these treatments were, on average, the least effective in controlling Calonectria infections. Otherwise, there were no significant increases in efficacy with fungicides plus BCA over fungicides alone. Thus, the application of boscalid + pyraclostrobin and cyprodinil + fludioxonil mixtures may also be used in large-scale applications to reduce Calonectria diseases because they effectively managed leaf and stem infections. Our comprehensive research applied previously acquired information on Calonectria disease management in nurseries, resulting in important data that affects integrated plans to fight these pathogens in accordance with European legislation

Ochraceocephala foeniculi gen. et sp. nov., a new pathogen causing crown rot of fennel in Italy

A new disease of fennel is described from Sicily (southern Italy). Surveys of the disease and sampling were conducted during spring 2017 and 2018 in Adrano and Bronte municipalities (Catania province) where this crop is widely cultivated. Isolations from the margin of symptomatic tissues resulted in fungal colonies with the same morphology. Pathogenicity tests with one isolate of the fungus on 6-month-old plants of fennel reproduced similar symptoms to those observed in nature. Inoculation experiments to assess the susceptibility of six different fennel cultivars to infection by the pathogen showed that the cultivars ‘Narciso’, ‘Apollo’, and ‘Pompeo’ were more susceptible than ‘Aurelio’, ‘Archimede’, and ‘Pegaso’. Phylogenetic analyses based on a matrix of the internal transcribed spacer (ITS), the large subunit (LSU), and the small subunit (SSU) rDNA regions revealed that the isolates represent a new genus and species within the Leptosphaeriaceae, which is here described as Ochraceocephala foeniculi gen. et sp. nov. This study improves the understanding of this new fennel disease, but further studies are needed for planning effective disease management strategies. According to the results of the phylogenetic analyses, Subplenodomus iridicola is transferred to the genus Alloleptosphaeria and Acicuseptoria rumicis to Paraleptosphaeria