Search Results (42)

Fungi of the genus Trichoderma show strong potential as biological control agents (BCAs) against grapevine trunk diseases (GTDs) through mechanisms like antibiotic metabolite production and lytic enzymes. This study evaluated the biocontrol activity of four native Trichoderma strains—T. gamsii T065 and T071, T. carraovejensis T154, and T. harzianum T214—against Phaeoacremonium minimum, Phaeomoniella chlamydospora, and Diplodia seriata. Culture filtrates obtained at 8, 16, and 24 days post-incubation were tested using antibiogram and mycelial inhibition assays. Strains T071, T154, and T214 effectively inhibited D. seriata, while T154 and T214 also suppressed P. chlamydospora. Nevertheless, the limited effectiveness of all filtrates against P. minimum suggests that antibiosis is not the predominant mechanism involved in its control. These findings highlight the potential of specific Trichoderma strains and incubation times to directly control GTD pathogens and support the development of scalable biocontrol solutions. Full article

The disposal of olive mill wastewater (OMWW) poses significant environmental challenges due to its high content of phytotoxic and pollutant compounds. This study aims to explore the chemical composition of OMWW derived from various olive varieties (Buža, Buža puntoža, Istarska bjelica, Leccino, and Rosinjola) and assess its antifungal potential against phytopathogenic fungi from the Botryosphaeriaceae family. OMWW samples were analyzed for their physicochemical properties, phenolic composition via LC-MS/MS, and antifungal activity against Botryosphaeria dothidea (Moug. ex Fr.) Ces. & De Not., Diplodia mutila (Fr.) Fr., D. seriata De Not., Dothiorella iberica A.J.L. Phillips, J. Luque & A. Alves, Do. sarmentorum (Fr.) A.J.L. Phillips, Alves & Luque, and Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips. Antifungal efficacy was tested at varying concentrations, alongside the phenolic compounds hydroxytyrosol and vanillic acid. Antifungal activity varied across fungal species and OMWW concentrations. Lower OMWW concentrations inhibited mycelial growth in some pathogens, while higher concentrations often had a stimulatory effect. Among the OMWW treatments, Leccino and Buža showed the most significant antifungal activity against species from the Botryosphaeriaceae family. The results demonstrated significant variability in OMWW composition, with Istarska bjelica exhibiting the highest concentrations of phenolic compounds, sugars, dry matter, and carbon and nitrogen content. The results also highlight the impact of acidification on the phenolic profile of OMWW. Treatment with HCl significantly altered the concentration of individual phenolic compounds, either enhancing their release or contributing to their degradation. Among the two compounds, vanillic acid showed greater efficacy than hydroxytyrosol. In addition, microorganisms isolated from OMWW, including Bacillus velezensis Ruiz-Garcia et al., Rhodotorula mucilaginosa (A. Jörg.) F.C. Harrison, Nakazawaea molendiniolei (N. Cadez, B. Turchetti & G. Peter) C. P. Kurtzman & C. J. Robnett, and Penicillium crustosum Thom, demonstrated antagonistic potential against fungal pathogens, with B. velezensis showing the strongest inhibitory effect. The greatest antagonistic effect against fungi was observed with the species Do. Iberica. The findings highlight the potential of OMWW as a sustainable alternative to chemical fungicides, simultaneously contributing to the management of waste and protection of plants through circular economy principles. Full article

Fraxinus angustifolia, the main ash species in Croatia in terms of economic and ecological importance, is affected by a severe dieback initially attributed to the fungal pathogen Hymenoscyphus fraxineus. Recently, another pathogen, Diplodia fraxini, has been shown to play a key role in ash dieback in several European countries. Therefore, because the dieback symptoms of ash trees observed in Croatia are typical of Botryosphaeriaceae attacks, the aim of this study was to define the etiology of F. angustifolia dieback. To this end, symptomatic shoots and branches and cross-sections of the main stem were sampled from 20 symptomatic trees at eight locations and analyzed for the presence of D. fraxini and other possible fungal pathogens. Diplodia fraxini was the fungus most frequently associated with branch cankers and dieback; it was isolated from 17 trees in all sites monitored, and its pathogenicity towards F. angustifolia was confirmed. The fungus was also associated with wood necrosis at the base of the trunk in two trees. Other fungi, namely H. fraxineus, Diaporthe eres, Diplodia seriata, Botryosphaeria dothidea, Armillaria gallica, and Lentinus tigrinus, were isolated sporadically. Full article

The antifungal effectiveness of essential oils (EOs) and their predominant components were tested on 14 phytopathogenic fungi isolated from olive trees. Commercial EOs from holy basil (Ocimum tenuiflorum L.), Chinese cinnamon (Cinnamomum aromaticum Ness), lemon (Citrus × limon), peppermint (Mentha × piperita L.), oregano (Origanum compactum Benth), and thyme (Thymus vulgaris L.) and components eugenol, e-cinnamaldehyde, limonene, menthol, carvacrol, and thymol were used. Antifungal efficacy was tested on six species from the Botryosphaeriaceae family: Botryosphaeria dothidea (Moug. ex Fr.) Ces. & De Not.; Diplodia mutila (Fr.) Fr.; D. seriata De Not.; Dothiorella iberica A.J.L. Phillips, J. Luque & A. Alves; Do. sarmentorum (Fr.) A.J.L. Phillips, Alves & Luque; and Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips. Other tested species included Biscogniauxia mediterranea (De Not.) Kuntze, B. nummularia (Bull.) Kuntze; Cytospora pruinosa Défago; Nigrospora gorlenkoana Novobr.; N. osmanthi Mei Wang & L. Cai; N. philosophiae-doctoris M. Raza, Qian Chen & L. Cai; Phaeoacremonium iranianum L. Mostert, Grafenhan, W. Gams & Crous; and Sordaria fimicola (Roberge ex Desm.) Ces. & De Not. The results show that Chinese cinnamon and oregano EOs, along with their components, completely inhibited the growth of all tested fungi, indicating their potential as biological control agents in sustainable agriculture. In contrast, the least effective treatments were the EOs derived from lemon and peppermint, as well as the components limonene, menthol, and thymol. Notably, the fungi Do. iberica and N. gorlenkoana were among the most sensitive to all the treatments applied. Full article

Botryosphaeria dieback disease is a significant grapevine trunk disease (GTD) caused by species of Botryosphaeriaceae in Chile and worldwide. Moreover, Botryosphaeriaceae have been described attacking fruit and nut crops in Chile. However, it remains unknown whether fungal isolates from tree hosts have the potential to infect grapevines in Chile. The aggressiveness and potential cross infection of species of Botryosphaeriaceae collected from crops (grapevines, apples, blueberries, and walnuts), was assessed on grapevines. Plant materials, including nursery cuttings, lignified canes, and green shoots of grapevine cultivars (Cabernet Sauvignon, Syrah, Sauvignon Blanc, Malbec, Aspirant Bouschet, and Merlot), were inoculated with Diplodia mutila, D. seriata, Dothiorella sarmentorum, Lasiodiplodia theobromae, Neofusicoccum arbuti, and N. parvum, under greenhouse and vineyard conditions. Regardless of the origin of the isolates, most species of Botryosphaeriaceae were pathogenic on plant materials, causing necrotic lesions of mean lengths from 11.9 to 86.2 mm using mycelial suspension and from 24.8 to 253.7 mm with mycelial plugs. Notably, Neofusicoccum species were the most aggressive, regardless of host origin. Other less aggressive species included L. theobromae, D. mutila, and D. seriata isolated from apple and walnut. This study highlights the potential of species of Botryosphaeriaceae from alternative fruit hosts as inoculum sources for grapevines in Chile. Full article

The fungi Botryosphaeriaceae are involved in olive declines in both the world hemispheres and in all continents where this species is cultivated. In Salento (Apulia, Italy), the Botryosphaeriaceae Neofusicoccum mediterraneum and N. stellenboschiana have been reported as the agents of a branch and twig dieback that overlaps with olive quick decline syndrome caused by Xylella fastidiosa subsp. pauca. In this study, we report the finding of Diplodia seriata, another Botryosphaeriaceae species, in Salento in Xylella fastidiosa-infected olive trees affected by symptoms of branch and twig dieback. Given that its presence was also reported in olive in the Americas and in Europe (Croatia) with different degrees of virulence, we were prompted to assess its role in the Apulian decline. We identified representative isolates based on morphological features and a multilocus phylogeny. In vitro tests showed that the optimum growth temperature of the isolates is around 25–30 °C, and that they are highly thermo-tolerant. In pathogenicity trials conducted over eleven months, D. seriata expressed a very low virulence. Nonetheless, when we imposed severe water stress before the inoculation, D. seriata significatively necrotized bark and wood in a time frame of 35 days. Moreover, the symptoms which resulted were much more severe in the trial performed in summer compared with that in autumn. In osmolyte-supplemented media with a water potential from −1 to −3 Mpa, the isolates increased or maintained their growth rate compared with non-supplemented media, and they also grew, albeit to a lesser extent, on media with a water potential as low as −7 Mpa. This suggests that olives with a low water potential, namely those subjected to drought, may offer a suitable environment for the fungus’ development. The analysis of the meteorological parameters, temperatures and rainfall, in Salento in the timeframe 1989–2023, showed that this area is subjected to a progressive increase of temperature and drought during the summer. Thus, overall, D. seriata has to be considered a contributor to the manifestation of branch and twig dieback of olive in Salento. Coherently with the spiral decline concept of trees, our results suggest that heat and drought act as predisposing/inciting factors facilitating D. seriata as a contributor. The fact that several adverse factors, biotic and abiotic, are simultaneously burdening olive trees in Salento offers a cue to discuss the possible complex nature of the olive decline in Salento. Full article

Apple canker disease, also named as apple Valsa canker, is one of the most destructive diseases for apples (Malus domestica Borkh.). Cytospora/Valsa spp. are the dominant causal agent of this disease, but many studies have revealed that fungi from some other genus can also cause typical apple canker symptoms. In this study, we performed fungal pathogen isolation from cankered ‘Fuji’ apple barks. Six representative morphologically different fungi (Strain 1–6) were further subjected to ITS sequencing and evolutionary analysis. Molecular identification results revealed that Strains 1–6 are Cytospora mali, Fusarium cf. solani, Alternaria alternata, C. mali, Diplodia seriata and F. proliferatum, respectively. All these fungi have been reported to be causal agents of apple diseases. By inoculating fungal plugs onto trunks of ‘Fuji’ apple trees, the pathogenicity of the six fungi were accessed. Only the inoculations of the two C. mali strains (Strain 1 and Strain 4) and the A. alternata strain (Strain 3) resulted in typical apple canker symptoms in trunks. It is worth noting that Strain 1 caused much more severe canker symptoms and higher pathogenicity incidence than the other two fungi. A. alternata has been identified as a pathogen causing diseases on apple fruits and leaves. By further assessing its pathogenicity on apple fruits and leaves, we verified that it can also cause typical fruit rot and leaf spot symptoms. To the best of our knowledge, this is the first report on apple canker disease caused by A. alternata in China. Our present study can provide a theoretical foundation for the prevention and control of apple canker disease. Full article

During 2021 and 2022, a field investigation was conducted in Istria, Croatia, searching for trees exhibiting signs of Botryosphaeria dieback. Samples of symptomatic trees were collected from 26 different locations and analysed. Isolates that morphologically corresponded to species from the Botryosphaeriaceae family were selected, and detailed morphological characterisation and molecular identification of the isolates were conducted. Based on morphological characteristics and phylogenetic analysis using the internal transcribed spacer (ITS), beta-tubulin (TUB2), and translation elongation factor 1-alpha (TEF1-α) regions, six species of fungi from the Botryosphaeriaceae family were identified: Botryosphaeria dothidea (Moug. ex Fr.) Ces. & De Not.; Diplodia mutila (Fr.) Fr.; Diplodia seriata De Not.; Dothiorella iberica A.J.L. Phillips, J. Luque & A. Alves; Dothiorella sarmentorum (Fr.) A.J.L. Phillips, Alves & Luque; and Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips. This is the first report of D. mutila, Do. sarmentorum, and Do. iberica causing Botryosphaeria dieback on olive trees in Croatia, and the first study investigating the resistance of Croatian olive varieties to species from the Botryosphaeriaceae family. Pathogenicity testing of selected isolates and assessment of variety resistance were conducted on four different olive varieties, namely Buža, Istarska bjelica, Leccino, and Rosinjola, using representative isolates of the mentioned species. The most aggressive species was found to be N. parvum. Olive varieties exhibited differences in susceptibility depending on the fungus they were infected with. Full article

Grapevine trunk diseases (GTDs) attack the vine’s wood, devastating vineyards worldwide. Chile is the world’s fourth-largest wine exporter, and Cabernet Sauvignon is one of the most economically important red wine varieties. Botryosphaeria dieback is an important GTD, and Diplodia seriata is one of the main pathogenic species. Biocontrol studies of these pathogens are commonly carried out at different incubation times but at a single temperature. This study aimed to evaluate the biocontrol effect of Chilean PGPB and grapevine endophytic bacteria against D. seriata at different temperatures. We analyzed the biocontrol effect of Pseudomonas sp. GcR15a, Pseudomonas sp. AMCR2b and Rhodococcus sp. PU4, with three D. seriata isolates (PUCV 2120, PUCV 2142 and PUCV 2183) at 8, 22 and 35 °C. Two dual-culture antagonism methods (agar plug diffusion and double plate) were used to evaluate the in vitro effect, and an in vivo test was performed with Cabernet Sauvignon cuttings. In vitro, the greatest inhibitions were obtained using the agar plug diffusion method and at a temperature of 8 °C, where Rhodococcus sp. PU4 obtains a 65% control (average) and Pseudomonas sp. GcR15a a 57% average. At 22 °C, only strains of Pseudomonas sp. show control. At 35 °C, one Pseudomonas strain shows the highest control (38%), on average, similar to tebuconazole (33%), and then Rhodococcus sp. (30%). In vivo, a biocontrol effect is observed against two D. seriata isolates, while the PUCV 2142 proves to be more resistant to control. The biocontrol ability at low temperatures is promising for effective control in the field, where infections occur primarily in winter. Full article

A three-year survey was conducted to estimate the incidence of grapevine trunk diseases (GTDs) in Greece and identify fungi associated with the disease complex. In total, 310 vineyards in different geographical regions in northern, central, and southern Greece were surveyed, and 533 fungal strains were isolated from diseased vines. Morphological, physiological and molecular (5.8S rRNA gene-ITS sequencing) analyses revealed that isolates belonged to 35 distinct fungal genera, including well-known (e.g., Botryosphaeria sp., Diaporthe spp., Eutypa sp., Diplodia sp., Fomitiporia sp., Phaeoacremonium spp., Phaeomoniella sp.) and lesser-known (e.g., Neosetophoma sp., Seimatosporium sp., Didymosphaeria sp., Kalmusia sp.) grapevine wood inhabitants. The GTDs-inducing population structure differed significantly among the discrete geographical zones. Phaeomoniella chlamydospora (26.62%, n = 70), Diaporthe spp. (18.25%, n = 48) and F. mediterranea (10.27%, n = 27) were the most prevalent in Heraklion, whereas D. seriata, Alternaria spp., P. chlamydospora and Fusarium spp. were predominant in Nemea (central Greece). In Amyntaio and Kavala (northern Greece), D. seriata was the most frequently isolated species (>50% frequency). Multi-genes (rDNA-ITS, LSU, tef1-α, tub2, act) sequencing of selected isolates, followed by pathogenicity tests, revealed that Neosetophoma italica, Seimatosporium vitis, Didymosphaeria variabile and Kalmusia variispora caused wood infection, with the former being the most virulent. To the best of our knowledge, this is the first report of N. italica associated with GTDs worldwide. This is also the first record of K. variispora, S. vitis and D. variabile associated with wood infection of grapevine in Greece. The potential associations of disease indices with vine age, cultivar, GTD-associated population structure and the prevailing meteorological conditions in different viticultural zones in Greece are presented and discussed. Full article

Species in the Botryosphaeriaceae are common plant pathogens, endophytes, and saprobes found on a variety of mainly woody hosts. Botryosphaeriaceae is a high-profile fungal family whose genera have been subjected to continuous revisions in recent years. Surveys conducted during 2019 and 2020 on several decaying woody hosts (from dead arial twigs, branches, stems, bark, and seed pods) in China and Thailand revealed a high diversity of Botryosphaeriaceae fungi. Identification of 16 Botryosphaeriaceae isolates was carried out based on both morphological characteristics and phylogenetic analyses of combined ITS, LSU, tef1-α, and tub2 sequence data. Four novel species (Dothiorella ovata, Do. rosacearum, Do. septata, and Lasiodiplodia delonicis) and seven previously known species (Botryosphaeria fujianensis, Diplodia mutila, Di. seriata, L. crassispora, L. mahajangana, Macrophomina euphorbiicola and Sphaeropsis eucalypticola) were identified while new hosts and geographical records were reported. This study indicates that the fungal family Botryosphaeriaceae seems to be common and widespread on a broad range of hosts in China and Thailand. Full article

Botryosphaeria dieback (BD) occurs in young and old plants. In the field, the prevalence and severity of the disease increase proportionally with the age of vineyards. Among the pathogens that cause BD, Diplodia seriata is the most prevalent species in Chile and other countries with a Mediterranean climate. To date, no information is available on the susceptibility of adult wood to infection by this pathogen since most of the pathogenicity tests have been carried out on 1- or 2-year-old shoots or detached canes. Therefore, a pathogenicity test was carried out on plants under field conditions, with inoculations in 1-year-old shoots and 2- and 10-year-old wood in grapevine cv. Cabernet Sauvignon. A pathogenicity test was carried out with two isolates of D. seriata. The results for the plants show that D. seriata was significantly more aggressive on the 10-year-old than on the one- or two-year-old tissue, where the lesions were 4.3 and 2.3 cm on average, respectively. These results were compared with the lesions obtained from two-year-old canes after the isolates were activated in grape berries. Also, the Chilean isolates of D. seriata were compared phylogenetically with those from other countries, and no major differences were found between them. Our results are consistent with the damage observed in the field, contributing to the knowledge of the epidemiology of this disease in Mediterranean climates. In the future, the effect observed in cv. Cabernet Sauvignon with D. seriata on virulence at different tissue ages should be tested for other BD-causing agents and wine varieties. Full article

Romania has a long history of grapevine culturing and winemaking. However, like any agricultural sector, viticulture faces devastating biological threats. Fungi responsible for grapevine trunk diseases (GTDs) and grape spoilage lead to considerable yield losses and a decline in grapevine quality. In the actual context, many countries, including Romania, have reoriented their approaches to minimize chemical inputs, which have been proven to be toxic and to have negative impacts on the environment, and to replace them with sustainable biocontrol strategies for the wine-growing sector. Within biocontrol strategies, Bacillus spp. is a well-known plant-protective bacteria with antifungal properties. Within this paper, six endophytic bacteria from various plant sources were studied. The bacterial strains were identified as B. pumilus, B. subtilis, and B. velezensis by sequencing their 16S rDNA region. Regardless of the in vitro test methods (using living bacterial cells, bacterial-cell-free supernatant (CFS), and volatile active compounds (VOCs)), B. velezensis strains revealed strong and broad antifungal activity against grape and grapevine fungal pathogens such as Aspergillus spp., Botrytis cinerea, Penicillium expansum, Diplodia seriata, Eutypa lata, Fusarium spp., Clonostachys rosea, Neofusicoccum parvum, and Stereum hirsutum. The functional antifungal genes encoding for difficidin, fengycin, iturins, macrolactin, and mycosubtilin were molecularly detected, which could support the proven antifungal activity of the endophytic strains. Lytic enzymes involved in fungal growth inhibition, such as chitinase, cellulase, and proteases, were also revealed to be produced by some of these bacterial strains. Various other in vitro tests, such as phosphate and phytate solubilization, phytohormone synthesis, the production of enzymes involved in the polyamine biosynthetic pathway, and pH as well as temperature tolerance tests were carried out to reveal the plant-beneficial potential of these bacterial strains. These results revealed that the B. velezensis strains, especially BAHs1, are the most suitable endophytes for grapevine biologic control, which could lead to the future development of sustainable management strategies. Full article

During a study of Botryosphaeriaceae species associated with grapevine trunk diseases in the Czech Republic, a collection of 22 Botryosphaeriaceae-like strains were isolated from four cultivars (Blaufränkisch, Pálava, Pinot Noir, and Welschriesling) in four distinct vineyards. Based on morphology and DNA sequence data (ITS, tub2, and tef), four species were identified: Botryosphaeria dothidea, Diplodia mutila, D. seriata, and Neofusicoccum parvum. These species are reported for the first time from grapevine in the Czech Republic. Relationships between vascular lesions and particular species were highlighted in this study. Diplodia seriata was the most frequently isolated species, present in all four sampled cultivars, while D. mutila was the least frequent, present only in ‘Pálava’. The cultivar Pinot Noir was the most tolerant host for Botryosphaeriaceae fungi. Full article

Grapevine trunk diseases (GTDs) cause significant yield losses worldwide and limit the lifespan of vineyards. In the last few years, using biological control agents (BCAs) for pruning wound protection has become a promising management strategy for the control of these pathologies. This study aimed to compare the antifungal activities of a grapevine-native Trichoderma harzianum isolate and a high-potential Bacillus velezensis strain against two pathogenic Botryosphaeriaceae species in artificially inoculated, potted, grafted plants under controlled greenhouse conditions, taking three commercial biocontrol products (based on T. atroviride I-1237, T. harzianum T-22, and Bacillus subtilis BS03 strains) as a reference. To reproduce certain field conditions more realistically, inoculation of the protective agents and the pathogens was conducted simultaneously immediately after pruning instead of allowing the BCAs to colonize the wounds before pathogen inoculation. Significant differences in necrosis lengths were detected for both Neofusicoccum parvum- and Diplodia seriata-infected plants, and a remarkable protective effect of Bacillus velezensis BUZ-14 was observed in all cases. Trichoderma-based treatments showed different efficacies against the two pathogenic fungi. While the three tested BCAs resulted in significant reductions in vascular necrosis caused by N. parvum, they did not significantly reduce D. seriata infection compared to the untreated inoculated control. The B. subtilis strain was not effective. The reported results provide support for the potential Bacillus velezensis may have for pruning wound protection against Botryosphaeriaceae fungi, encouraging its evaluation under natural field conditions. Full article