Phytotoxic metabolites produced by Botryosphaeriaceae involved in grapevine trunk diseases

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

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

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

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

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

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

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

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

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

Diplodia fraxini and Diplodia subglobosa: The Main Species Associated with Cankers and Dieback of Fraxinus excelsior in North-Eastern Italy

In Italy, after the first report in Friuli-Venezia Giulia along the border with Slovenia in 2009, ash dieback has successively been reported in Veneto, Tuscany and Trentino-Alto Adige. Given its alarming expansion in European ash formations along the sub-montane belt of north-eastern Italy and the limited information about the associated fungal microorganisms; since 2017, a study has been conducted in order to isolate and characterize the fungal species involved in the aetiology of the disease. The surveys were conducted in six ash–maple forests distributed along the Veneto and Friuli-Venezia Giulia pre-Alpine regions (Italy). In each site, the health status of ash trees was assessed and a sample (shoot or branch) with the typical symptoms of the disease was taken from ten trees to isolate the associated pathogens. The fungal colonies developed were identified using morphological features and DNA sequences. The 60 samples processed yielded a total of 109 fungal isolates belonging to 9 families including: Botryosphaeriaceae (62 isolates), Diaporthaceae (18), Nectriaceae (10), Didymellaceae (9), Helotiaceae (5), Diatrypaceae (2), Didymosphaeriaceae (1), Phaeosphaeriaceae (1) and Valsaceae (1). In particular, three species—Diplodia subglobosa, Diplodia fraxini and Diaporthe eres—were isolated with high frequency, while Hymenoscyphus fraxineus was isolated from only five plants distributed in four sites. The pathogenicity tests, conducted on 3-year-old seedlings, detached branches (3–4 cm diameter), and leaves of Fraxinus excelsior, showed that Diplodia fraxini is the most virulent species and the only one able to reproduce the symptoms observed in nature. Overall, the results obtained emphasize that several fungal pathogens are involved in the aetiology of the disease, many of which belong to the Botryosphaeriaceae family