252 research outputs found

    Phytotoxic metabolites produced by Botryosphaeriaceae involved in grapevine trunk diseases

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    Fungi belonging to the Botryosphaeriaceae family are well known as cosmopolitan pathogens, saprophytes and endophytes and occur on a wide range of hosts including grapevine. More recently, a new species of Lasiodiplodia was isolated from declining grapevines in Sardinia (Italy). This still undescribed species showed to produce in liquid culture several phytotoxic secondary metabolites. In this communication the chemical and biological characterization of these bioactive secondary metabolites is discussed together with their role in the pathogenesis process

    Pinofuranoxins A and B, Bioactive Trisubstituted Furanones Produced by the Invasive Pathogen Diplodia sapinea

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    Two new bioactive trisubstituted furanones, named pinofuranoxins A and B (1 and 2), were isolated from Diplodia sapinea, a worldwide conifer pathogen causing severe disease. Pinofuranoxins A and B were characterized essentially by NMR and HRESIMS spectra, and their relative and absolute configurations were assigned by NOESY experiments and computational analyses of electronic circular dichroism spectra. They induced necrotic lesions on Hedera helix L., Phaseolus vulgaris L., and Quercus ilex L. Compound 1 completely inhibited the growth of Athelia rolfsii and Phytophthora cambivora, while 2 showed antioomycetes activity against P. cambivora. In the Artemia salina assay both toxins showed activity inducing larval mortality

    First report of Neofusicoccum australe associated with grapevine cordon dieback in Italy

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    This is the first report of Neofusicoccum australe associated with grapevine dieback in Italy. Fungal isolates obtained from symptomatic tissues were identified on the basis of morphological and cultural characteristics as well as ITS sequence data. Pathogenicity was verified by inoculation of excised green grapevine shoots from cv. Cannonau under controlled laboratory condition

    The potential for pesticide trunk injections for control of thousand cankers disease of walnut

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    Thousand cankers disease, caused by the pathogen Geosmithia morbida vectored by the bark beetle Pityophthorus juglandis, has emerged as an important disease of walnut trees in Europe. The present study was performed to evaluate the efficacy of trunk injections of four commercial fungicides and one insecticide for control of the fungus and its vector. Laboratory tests indicated that fungicides containing prochloraz + tetraconazole were the most effective. Field trials on non-infected trees allowed for the selection of a mixture containing prochloraz and tetraconazole (Binal Pro), the insecticide abamectin (Vertimec EC) and the adjuvant 2-(2-ethoxyethoxy) ethanol (CarbitolTM) as having rapid host uptake. Injections of this formulation in naturally infected black walnut trees reduced the presence of G. morbida, supporting trunk injection as an efficient and low impact technique to manage fungal damage on infected trees

    First report of Neofusicoccum parvum and Phytophthora palmivora causing fruit rot of pomegranate in Italy

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    Severe pomegranate yield losses due to fruit diseases have recently been observed in several orchards in Veneto (north-eastern Italy). Given the economic relevance of these emerging diseases, an in-depth study was conducted in ten orchards distributed in the main producing areas in order to investigate the aetiology. From autumn 2020 to autumn 2023, eighty-two symptomatic fruits were sampled to isolate the causal agents. Based on morphology, colony appearance and DNA sequence data, seventy-seven isolates were obtained and identified. These included Coniella granati (Fam. Schizoparmaceae, 39 isolates), Neofusicoccum parvum (Fam. Botryosphaeriaceae, 29) and Phytophthora palmivora (Fam. Peronosporaceae, 9). Pathogenicity trials conducted on ripe pomegranate fruits confirmed the aggressiveness of the three species. Results obtained have allowed us to expand knowledge on emerging pomegranate pathogens. Neofusicoccum parvum and P. palmivora are reported here for the first time as fruit rot agents on pomegranate in Italy

    Principali avversità biotiche dell'eucalipto in Sardegna

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    Il genere Eucalyptus (fam. Mirtaceae) è originario dell'Oceania e include oltre 600 specie di alberi e arbusti sempreverdi. Nell'Italia centro meridionale la specie più diffusa è l'Eucalyptus camaldulensis Dhenh. La grave diffusione di fenomeni di deperimento e di moria di piante nei popolamenti di eucalipto della Sardegna ha richiesto indagini di carattere entomologico e patologico, condotte in 12 aree dell'Isola

    Endophytic and epiphytic phyllosphere fungal communities are shaped by different environmental factors in a mediterranean ecosystem

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    The online version of this article (https://doi.org/10.1007/s00248-018-1161-9) contains supplementary material, which is available to authorized users.The diversity and factors influencing fimgal assemblages in phyllosphere of Mediterranean tree species have been barely studied, especially when endophytic and epiphytic communities are simultaneously considered. In this work, the endophytic and epiphytic fungal communities from olive tree phyllosphere were studied. This tree species is natural from the Mediterranean region and adapted to grow under adverse climatic conditions. The main objectives were to determine whether there are differences between both fungal communities and to examine whether different abiotic (climate-related) and biotic (plant organs) factors play a pivotal role in structuring these communities. Both communities differed in size and composition, with epiphytic community being richer and more abundant, displaying also a dominance of melanized fungi. Season was the major driver of community composition, especially of epiphytes. Other drivers shaping epiphytes were wind speed and temperature, while plant organ, rainfall, and temperature were the major drivers for endophytic composition. In contrast, canopy orientation caused slight variations in community composition of fungi, but with distinct effects in spring and autumn seasons. In conclusion, epiphytic and endophytic communities are not driven by the same factors. Several sources of variation undergo complex interactions to form and maintain phyllosphere fungal community in Mediterranean climates. Climatic parameters have influence on these fungal communities, suggesting that they are likely to be affected by climate changes in a near future.This work is funded by FEDER funds through COMPETE (Programa Operacional Factores de Competitividade) and by national funds by FCT (Fundacao para a Ciencia e a Tecnologia) within the framework of the project EXCL/AGR-PRO/0591/2012. T. Gomes thanks FCT, POPH-QREN, and FSE for PhD SFRH/BD/98127/2013 grant
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