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Field surveys were conducted in British Columbia fruit tree growing regions to determine the incidence of dieback and to identify the main fungal species causing cankers. Fruit trees showing cankers and dieback symptoms were recorded from 94% of orchards and 5.5% of trees surveyed. Overall, higher dieback incidence was observed in cherry than apple with 33% of cherry blocks showing between 5% and 26% of trees affected. Morphological studies along with DNA sequencing of the internal transcribed spacer (ITS) including the 5.8S rDNA, and parts of the translation elongation factor 1-α (TEF1), beta-tubulin (TUB2), and actin (ACT1) genes, identified seven fungi for the first time in fruit trees in Canada, including Calosphaeria pulchella, Cytospora parasitica, Cytospora populicola, Cytospora sorbicola, Ilyonectria robusta, Nectria dematiosa, and Phaeoacremonium minimum. In addition, this study reports for the first time Diplodia mutila and Diplodia seriata from cankers in sweet cherry in Canada. The already known fungal pathogens Neofabraea perennans and Neonectria ditissima were also identified. Pathogenicity studies showed N. ditissima and C. sorbicola to cause the largest vascular lesions in apple and cherry, respectively. This study identified the main fungal pathogens causing tree fruit cankers and dieback in British Columbia providing important information for the development of effective control strategies. [ABSTRACT FROM AUTHOR]

Despite studies associating Fusarium spp. with grapevine decline since late 1970s, no consensus has been reached regarding the roles these fungi play in grapevine health. Recent studies in British Columbia, Canada, assessed prevalence of grapevine trunk diseases (GTDs) in young and mature vineyards, and the presence of GTD fungi in ready-to-plant nursery material sold in Canada. This study characterized the Fusarium spp. isolated from grapevines in BC by sequencing part of the translation elongation factor 1-alpha (TEF1) gene, and carried out pathogenicity studies to determine whether Fusarium plays a role in grapevine decline. Fusarium spp. were isolated from 9.8% of samples collected from young vines (≤ 8-year-old), and 7.3% from mature vines (> 8-year-old), showing decline symptoms in commercial vineyards. Fusarium was also isolated from 43.9% of ready-to-plant dormant grapevines analyzed from four nurseries. Fusarium incidence varied between plants within the same nursery and between plants from the different nurseries. DNA sequences of TEF1 allowed identification of Fusarium oxysporum, F. proliferatum, F. ramigenum, and a Fusarium sp. Pathogenicity studies were conducted in 1-year-old dormant rooted ‘Chardonnay’ plants grafted onto ‘3309C’ rootstock, and treatments included: i) whole plant, ii) trimming of roots, iii) cut at rootstock basal ends, and iv) trimming of roots plus cut at rootstock basal ends. Plants were inoculated using standardized methods, and were then planted in a greenhouse. Fusarium was compared with Dactylonectria macrodidyma, D. pauciseptata and Ilyonectria liriodendri used as positive controls. The Fusarium spp. caused necroses in rootstock roots and basal ends that were similar to those caused by blackfoot fungi. Fusarium spp. and black-foot fungi reduced root and shoot dry weights when compared with non-inoculated controls, but no statistically significant differences were recorded for most treatments. This study is the first in Canada to identify Fusarium spp. from grapevines. Though Fusarium was common in these grapevines, pathogenicity tests suggest that the identified Fusarium spp. were weakly pathogenic to ‘3309C’ rootstock grapevines. [ABSTRACT FROM AUTHOR]

Young vine decline (YVD) is a grapevine trunk disease (GTD) which results in stunted and delayed growth, reduced yield, root necrosis and eventually death of young vines. Given losses associated with root trunk disease, and increasing limits on chemical fungicides, there is a need for sustainable approaches to combat disease; (1) Cover cropping is a commonly used practice in agricultural systems and has potential to reduce disease in vineyards but there is a risk that cover crop species may act as a host for grapevine pathogens, increasing the risk of infection; (2) We tested 25 plant species commonly used in cover crops to assess their potential to act as a host for a Ilyonectria liriodendri, which is a causal agent of young vine decline. We inoculated greenhouse pots with a pathogeninc strain of Ilyonectria and assayed the roots for the presence of the pathogen; (3) Of the 25 cover crops tested, many of the species showed increased root abundance of Ilyonectria, compared to background levels. In particular phacelia (Phacelia tanacetifolia) and buckwheat (Fagopyrum esculentum) showed very high levels of root colonization. (4) This is the first study to our knowledge that highlights the potential of cover crops to soil borne fungal pathogens. [ABSTRACT FROM AUTHOR]

Black-foot (BF) disease of grapevines in nurseries and young vineyards is caused by soil-borne Cylindrocarpon-like asexual morphs. They can be found both in symptomatic and asymptomatic vines, being spread to new grape growing areas during vineyard establishment. In this study, 42 grapevine nurseries located in different geographical regions in Turkiye were surveyed in 2021 to determine the presence of BF pathogens on asymptomatic marketable plants. Black-foot fungi were isolated from the roots or basal ends of asymptomatic dormant vines in 39 of the nurseries (92.9%). The percentage of isolation of BF pathogens ranged from 1.4 to 51.4% (average 18.4%). Seven species: Cylindrodendrum alicantinum, Cylindrocladiella peruviana, Dactylonectria macrodidyma, D. novozelandica, D. torresensis, Ilyonectria liriodendri, and I. robusta were identified based on DNA sequencing of histone H3 gene and phylogenetic analyses, D. torresensis being the most frequent. From these species Ca. peruviana, D. novozelandica and I. robusta were detected for the first time on grapevines in Turkiye. Pathogenicity tests on 1103P rootstock cuttings revealed that all species significantly decreased root biomass and increased root disease severity index, when compared with the non-inoculated control, D. novozelandica being the most virulent. Pathogenicity of Cm. alicantinum to grapevine was confirmed for the first time, thus this species should be included as causal agent of BF of grapevines. These findings point out that BF pathogens are highly prevalent in the nurseries and could represent a serious threat for Turkish viticulture. [ABSTRACT FROM AUTHOR]

Dieback of young Quercus robur seedlings can limit natural regeneration in mixed‐species forest stands in Poland. The aim of this study was to examine the role of fungi in the dieback of oak seedlings in central Europe. Fungi were isolated from the stems and roots of Q. robur, from both healthy seedlings and seedlings with symptoms, that were sampled from four stands in Poland. In total, 111 distinct taxa were identified. Ascomycota was dominant, representing 95.6% of the isolates. Among the taxa identified, Alternaria alternata, Colletotrichum fioriniae, Colletotrichumgodetiae, Coniella quercicola, Diaporthe eres, Gnomoniopsis paraclavulata, Ilyonectria rufa, Mucor genevensis, Penicillium glandicola, Tubakia dryina, and Umbelopsis changbaiensis were most frequently isolated, and were consistently found in stems and roots of both healthy and diseased plants. The community compositions of fungi in healthy and diseased stems were similar, although Fusarium species, especially Fusarium sp. 1 (FTSC 5) and F. sporotrichioides, were found mainly in seedlings with symptoms. The pathogenicity of the most consistently isolated species from stems and roots of diseased seedlings was tested on Q. robur seedlings. F. sporotrichioides caused the largest lesions on inoculated seedlings. Six weeks after inoculation, D. eres, C. fioriniae, G. paraclavulata, T. dryina, and F. sporotrichioides killed 0%–18.8% of seedlings, while I. rufa and Ilyonectriapseudodestructans did not cause any lesions or other symptoms. This study is the first comprehensive report suggesting that massive fungal attack can lead to oak seedling dieback in mixed‐species forest stands in central Europe. [ABSTRACT FROM AUTHOR]

Ilyonectria mors-panacis , previously Cylindrocarpon destructans , is the main plant pathogen responsible for the fungal disease ginseng root rot. This economically important disease, also called disappearing root rot, reduces crop yields by an average of 30% at harvest. While the disease is well studied from ecological and genomic perspectives, the role of I. mors-panacis secondary metabolites in the disease process is not well understood. Our previous metabolomics study showed Ilyonectria strains that cause ginseng root rot produce mixtures of putative resorcylic acid lactones, whereas avirulent strains did not, and collectively synthesize fewer metabolites. To confirm these metabolomics findings, we isolated and characterized the secondary metabolites from I. mors-panacis DAOMC 251601, a strain that causes ginseng root rot. From its EtOAc soluble culture filtrate extract, eight resorcylic acid lactones (1 - 8), including chlorinated and non-chlorinated congeners, were characterized by HRMS and spectroscopic approaches (NMR, OR, UV). The structure of one new metabolite, named radicicol E (1), was elucidated and additional spectroscopic data for the known compound nordinonediol (2) are reported. Further, radicicol (9) production was confirmed by comparison to a standard. The roles that resorcylic acid lactones and the siderophore N,N′,N" triacetylfusarine C have in promoting Ilyonectria ginseng root rot are also discussed. [Display omitted] • Studied the metabolites from an Ilyonectria mors-panacis strain that causes the disease ginseng root rot. • Eight resorcylic acid lactones, including one new compound, were isolated and characterized. • Resorcylic acid lactones are proposed to contribute to the disease process by supressing the plants immune system. [ABSTRACT FROM AUTHOR]

Three almond nurseries were prospected in the South of Spain (Sevilla) to evaluate the sanitary status of the nursery plant material. Samples consisted of main roots, secondary roots and six-month-old basal stems 'GxN-15', 'Nemaguard', 'Cadaman', 'Rootpac-40' and 'Rootpac-20' rootstocks planted in the soil, and twigs of mother plants from 'Lauranne', 'Guara', 'Marcona', 'Marta' and 'Ferragnes' almond cultivars. Endophytic and potential pathogenic fungi were identified in mother plants and 70 Cylindrocarpon-like anamorph isolates were detected in the root system and basal stems of analyzed rootstocks. Based on partial sequencing of the his3 gene and multilocus phylogenetic analysis of the concatenated ITS, tub2, his3 and tef1-α partial sequences, seven Cylindrocarpon-like anamorph species were identified as Dactylonectria torresensis, D. novozelandica, D. macrodidyma, Ilyonectria liriodendri, Neonectria sp. 1, N. quercicola and Cylindrocladiella variabilis. Pathogenicity was assessed on young healthy detached twigs of 'Guara' almond cultivar and one-year-old 'Lauranne' potted almonds grafted onto 'GxN-15' rootstocks. Among the seven Cylindrocarpon-like anamorph species, I. liriodendri, Neonectria sp. 1 and N. quercicola were the most aggressive. Inoculated detached shoots developed necrotic lesions 15 days after inoculation. Inoculated trees showed sectorized necrosis in the main and secondary roots and the basal stem of the rootstock 5 months after inoculation. The most aggressive species were able to cause necrosis also in the grafted cultivar, and I. liriodendri, and N. quercicola also reduced the root biomass. This is the first report of Cylindrocarpon-like anamorph species causing root and basal rot of almonds. [ABSTRACT FROM AUTHOR]

Black foot disease is one of the main grapevine root diseases observed worldwide and is especially problematic in New Zealand. Arbuscular mycorrhizal fungi (AMF) have been shown to reduce infection and mitigate the effect of black foot disease on grapevine rootstocks. In contrast to prior studies, which have limited their focus to the effect of one, two or a combination of only a small number of AMF species, this study used whole AMF communities identified from 101-14, 5C and Schwarzmann rootstocks sampled from New Zealand vineyards. The effect of AMF on black foot disease was investigated in a 'home' and 'away' experiment using three commercial grapevine rootstocks. The study produced some evidence that AMF treatments lowered disease incidence at 5 cm and disease severity in vines by 40% to 50% compared to the vines inoculated with the pathogen only. This work also showed that the presence of high disease incidence may have limited the potential disease protective effect of AMF community. However, despite the high disease incidence and severity, AMF inoculation increased vine growth parameters by 60% to 80% compared to the vines inoculated with the pathogen only. This study is the first to provide an understanding on how young grapevine rootstocks inoculated with their 'home' and 'away' AMF communities would respond to challenge with a black foot pathogen species mixture. Further research is required to understand the mechanistic effect of AMF colonization on the increase of grapevine growth parameters under high black foot disease pressure. [ABSTRACT FROM AUTHOR]

Young vine decline (YVD) is a grapevine trunk disease (GTD) which results in stunted and delayed growth, reduced yield, root necrosis and eventually death of young vines. Given losses associated with root trunk disease, and increasing limits on chemical fungicides, there is a need for sustainable approaches to combat disease; (1) Cover cropping is a commonly used practice in agricultural systems and has potential to reduce disease in vineyards but there is a risk that cover crop species may act as a host for grapevine pathogens, increasing the risk of infection; (2) We tested 25 plant species commonly used in cover crops to assess their potential to act as a host for a Ilyonectria liriodendri, which is a causal agent of young vine decline. We inoculated greenhouse pots with a pathogeninc strain of Ilyonectria and assayed the roots for the presence of the pathogen; (3) Of the 25 cover crops tested, many of the species showed increased root abundance of Ilyonectria, compared to background levels. In particular phacelia (Phacelia tanacetifolia) and buckwheat (Fagopyrum esculentum) showed very high levels of root colonization. (4) This is the first study to our knowledge that highlights the potential of cover crops to soil borne fungal pathogens.

Aim: The purpose of this study was to evaluate the in vitro and in vivo efficiency of derivatives of 8‐Hydroxyquinoline (8HQ) in controlling the fungus Ilyonectria liriodendri. Methods and Results: The in vitro tests consisted of assessing its susceptibility to the minimal inhibitory concentration (MIC) and the inhibition of mycelial growth. While the in vivo tests consisted of applying and assessing the most effective products for the protection of wounds, in both preventive + curative and curative forms. The MIC values for PH 151 (6·25 µg ml−1) showed better results when compared to the fungicides tebuconazole (>50 µg ml−1) and mancozeb (12·5 µg ml−1 for strain 176 and 25 µg ml−1 for strain 1117). PH 151 significantly inhibited mycelial growth, while mancozeb did not differ from the control. In in vivo tests, PH 151 again demonstrated excellent results in vitro, especially when applied preventively. Conclusions: The derivative of 8HQ PH 151 was effective in controlling the fungus I. liriodendri in vitro and proved to be a promising option for protecting wounds. Significance and Impact of the Study: This study points to the prospect of an effective and safe preventive antifungal product, which would enable the use of pesticides in vine culture to be reduced. [ABSTRACT FROM AUTHOR]

Background and aims: Root rot is a catastrophic disease of perennial medicinal plants which could be caused by various soil-borne fungal pathogens. However, the understanding of the composition and diversity of root rot pathogenic fungi, their successions and potential drivers remains limited. Methods: Sanqi ginseng (Panax notoginseng) was selected as a model plant and the rhizosphere soils of root rot-infected Sanqi ginseng at different growth years were collected. Phenolic acid content, pathogen abundance, and fungal microbiota were examined by using the high-performance liquid chromatography (HPLC), real-time PCR and Miseq sequencing. Results: Pathogenic agents dominated in the rhizospheric fungal microbiota of rotten Sanqi ginseng and mainly comprised of Ilyonectria, Plectosphaerella, Clonostachys, Gibberella, Pestalotiopsis, Fusarium, and Chalara, with Ilyonectria and Fusarium being most abundant. The composition of pathogenic microbiota, but not α-diversity indices, changed considerably with Sanqi ginseng growth. The shifts of phenolic acid profile were an important driver in changes of rhizosphere pathogenic microbiota, and same phenolic acid exerted distinct functions on differential pathogenic taxa. Particularly, the contents of p-coumaric acid, ferulic acid, and benzoic acid were positively correlated with the abundance of genus Fusarium and negatively correlated with the abundance of genus Ilyonectria. Conclusions: Root rot-infected Sanqi ginseng rhizosphere harbors dynamically pathogenic microbiota driven by the shift of phenolic acids. This study provides insights into the composition, variation, and driver of root rot pathogenic microbiota; these insights are important for the development of targeted measure for the prevention and control of root rot diseases. [ABSTRACT FROM AUTHOR]

Host preference of root endophytes of the three European tree species of Norway spruce (Picea abies), common ash (Fraxinus excelsior), and sycamore maple (Acer pseudoplatanus) were investigated in two forest stands near Zurich, Switzerland. The focus was placed on members of the Phialocephala fortinii s.l. (sensu lato)—Acephala applanata species complex (PAC), as well as other dark septate endopyhtes (DSE). PAC species were identified based on 13 microsatellite loci. Eleven PAC species were found, with Phialocephala helvetica, P. europaea being the most frequent. All but cryptic species 12 (CSP12) preferred Norway spruce as a host. Though very rare in general, CSP12 was most frequently isolated from maple roots. Regarding the abundant PAC species, P. helvetica and P. europaea, the preference of spruce as a host was least pronounced in P. europaea, as it was also often isolated from ash and maple. It is the first record of PAC found on common ash (Fraxinus excelsior). Cadophora orchidicola, a close relative of PAC, has frequently been isolated from ash. Various species of the Nectriaceae (Cylindrocarpon spp.) have often been isolated, particularly from maple roots. By comparison, Pezicula spp. (Cryptosporiopsis spp.) was found to be abundant on all three hosts. Phomopsis phaseoli exhibits a clear preference for spruce. [ABSTRACT FROM AUTHOR]

Three almond nurseries were prospected in the South of Spain (Sevilla) to evaluate the sanitary status of the nursery plant material. Samples consisted of main roots, secondary roots and six-month-old basal stems ‘GxN-15’, ‘Nemaguard’, ‘Cadaman’, ‘Rootpac-40’ and ‘Rootpac-20’ rootstocks planted in the soil, and twigs of mother plants from ‘Lauranne’, ‘Guara’, ‘Marcona’, ‘Marta’ and ‘Ferragnes’ almond cultivars. Endophytic and potential pathogenic fungi were identified in mother plants and 70 Cylindrocarpon-like anamorph isolates were detected in the root system and basal stems of analyzed rootstocks. Based on partial sequencing of the his3 gene and multilocus phylogenetic analysis of the concatenated ITS, tub2, his3 and tef1-α partial sequences, seven Cylindrocarpon-like anamorph species were identified as Dactylonectria torresensis, D. novozelandica, D. macrodidyma, Ilyonectria liriodendri, Neonectria sp. 1, N. quercicola and Cylindrocladiella variabilis. Pathogenicity was assessed on young healthy detached twigs of ‘Guara’ almond cultivar and one-year-old ‘Lauranne’ potted almonds grafted onto ‘GxN-15’ rootstocks. Among the seven Cylindrocarpon-like anamorph species, I. liriodendri, Neonectria sp. 1 and N. quercicola were the most aggressive. Inoculated detached shoots developed necrotic lesions 15 days after inoculation. Inoculated trees showed sectorized necrosis in the main and secondary roots and the basal stem of the rootstock 5 months after inoculation. The most aggressive species were able to cause necrosis also in the grafted cultivar, and I. liriodendri, and N. quercicola also reduced the root biomass. This is the first report of Cylindrocarpon-like anamorph species causing root and basal rot of almonds.

Black foot disease of grapevines is a major economic issue for the viticulture industry worldwide. The disease is mainly associated with a complex of pathogen species within the genera Dactylonectria and Ilyonectria. The susceptibility of six grapevine rootstock cultivars to black foot disease under field conditions was assessed. Callused rootstocks of 101-14, 5C, 420A, Riparia Gloire, Schwarzmann and 3309C were planted into soil containing low natural pathogen populations or inoculated with isolates representing the species diversity in New Zealand. Disease incidence, disease severity and dry weight accumulation were assessed after 8 months of growth. Root and shoot dry weights were not significantly affected by inoculation treatment, but differed among rootstock cultivars, with cultivar 420A having the lowest root and shoot dry weight, cultivar 3309C having the largest shoot dry weight and cultivar 5C the largest root dry weight. The relative susceptibility of rootstocks differed significantly depending on whether they were grown under low natural inoculum pressure or a higher pressure in artificially inoculated soil. Schwarzmann and Riparia Gloire rootstock cultivars were the least susceptible under natural low inoculum pressure, but were the most susceptible in inoculated soil. In contrast, 5C was one of the most susceptible under low inoculum levels but was the least susceptible under high pathogen pressure. The result of the study indicate that black foot pathogen inoculum levels in soil affect the relative susceptibility of grapevine rootstocks to infection, and may have implications for the selection of rootstocks for planting. [ABSTRACT FROM AUTHOR]

BACKGROUND Black foot disease (BFD) is one of the main fungal diseases associated with young grapevine decline. Trichoderma holds the potential to be used as biocontrol agent against this disease, though variable success of colonization were found when applied to nursery vines in previous studies. Therefore, field experiments were established to evaluate different methods of application of Trichoderma atroviride, and to evaluate the efficacy of different commercial Trichoderma products on BFD in nursery vines post callusing over two seasons. RESULTS: Only in one season of the trial evaluating different products did all of the Trichoderma treatments significantly lower the black foot infections in the rootstock bases of the vines (mean black foot pathogen incidence of 1.00 to 2.50% in Trichoderma treated vines versus 6.50% in the untreated control). When comparing tissue parts, the base of the vine and collar roots had significantly higher Trichoderma colonization than the middle and root tip parts. Significantly less BFD pathogens were isolated from the base in comparison to the roots. These colonization trends were found for both field trials over both seasons. The different application methods showed that dipping of basal ends in the dry formulation followed by monthly soil drenches consistently gave higher colonization [mean Trichoderma incidence in the bases were 39.20% (2016/2017) and 28.00% (2017/2018)], while the 1 h soak of the bases of vines was not effective [mean Trichoderma incidence in the bases were 8.80% (2016/2017) and 4.00% (2017/2018)] and did not differ from the untreated control. CONCLUSION: Even though Trichoderma spp. were not sufficient to prevent infections by BFD pathogens, a certain degree of protection was obtained in the basal ends, which may contribute to longevity of the vines once planted in the vineyard. [ABSTRACT FROM AUTHOR]

Panax ginseng rusty root rot caused by the Ilyonectria species complex is a devastating disease, and it is one of the main factors contributing to the difficulty in continual cropping. Rusty root rot occurs in all ginseng fields, but little is known about the taxonomy of the fungal pathogen complex, especially Ilyonectria and Ilyonectria-like species. Rusty root rot samples were collected from commercial ginseng cultivation areas of China, and the pathogens were isolated and purified as single spores. Based on the combination analysis of multiple loci (rDNA-ITS, TUB, HIS3, TEF, ACT, LSU, RPB1, RPB2, and SSU) and morphological characteristics, the pathogens causing ginseng rusty root rot were determined. Fungal isolates were obtained from infected roots in 56 locations within main cultivation areas in China. A total of 766 strains were identified as Ilyonectria, Ilyonectria-like and Rhexocercosporidium species, including I. robusta (55.0%), I. communis (21.7%), I. mors-panacis (10.9%), I. pseudodestructans (2.0%), I. changbaiensis (1.3%), I. qitaiheensis (1.3%), Neonectria obtusispora (2.0%), Dactylonectria torresensis (0.5%), D. sp. (0.5%), and R. panacis (1.5%), and four novel species, Thelonectria ginsengicola (1.0%), T. jixiensis (1.0%), T. mulanensis (0.8%) and T. fusongensis (0.5%), with a total of 14 species. As the pathogen present in the highest proportion, I. robusta was the most prevalent and damaging species, unlike the pathogens reported previously. All of the examined strains were proven to cause ginseng rusty root rot. Our results indicate that the taxonomy of the fungal complex associated with ginseng rusty root rot includes Ilyonectria, Ilyonectria-like genera (Dactylonectria, Neonectria, and Thelonectria) and Rhexocercosporidium.

Management of black foot disease (BFD) of grapevines is difficult due to limited control options. Biological control fungi, in particular Trichoderma spp., hold potential as part of integrated management of BFD. Trichoderma atroviride, T. fertile, T. harzianum and T. virens were evaluated in vitro against four common BFD pathogens in South Africa, including Campylocarpon fasciculare, C. pseudofasciculare, Dactylonectria macrodidyma and Ilyonectria liriodendri. Effects of Trichoderma volatile organic and diffusible antifungal compounds (VOCs and DACs) and direct antagonistic effects were determined in Petri dish assays. Pathogen growth inhibition was determined in the VOC and DAC assays. Macro- and microscopic observations of fungus interaction zones were made in dual culture plate assays. Greater BFD pathogen growth inhibition occurred with the DACs than the VOCs. For both classes of compounds, D. macrodidyma was the most sensitive pathogen (100% inhibition by DACs and 65% by VOCs). In some cases, depending on the Trichoderma spp. isolate, growth stimulation occurred for I. liriodendri, C. fasciculare and C. pseudofasciculare. Macroscopically observed Trichoderma and BFD pathogen interactions included total or partial overgrowth, often associated with sporulation of the Trichoderma spp., and arrested growth or the formation of inhibition zones. Microscopic interactions included adhesion of the Trichoderma to pathogen hyphae, pathogen hyphae swelling, malformation and disintegration. In general, in vitro efficacy was isolate-dependent, both for Trichoderma spp. and the BFD pathogen.

Black foot disease is one of the main grapevine root diseases observed worldwide and is especially problematic in New Zealand. Arbuscular mycorrhizal fungi (AMF) have been shown to reduce infection and mitigate the effect of black foot disease on grapevine rootstocks. In contrast to prior studies, which have limited their focus to the effect of one, two or a combination of only a small number of AMF species, this study used whole AMF communities identified from 101-14, 5C and Schwarzmann rootstocks sampled from New Zealand vineyards. The effect of AMF on black foot disease was investigated in a ‘home’ and ‘away’ experiment using three commercial grapevine rootstocks. The study produced some evidence that AMF treatments lowered disease incidence at 5 cm and disease severity in vines by 40% to 50% compared to the vines inoculated with the pathogen only. This work also showed that the presence of high disease incidence may have limited the potential disease protective effect of AMF community. However, despite the high disease incidence and severity, AMF inoculation increased vine growth parameters by 60% to 80% compared to the vines inoculated with the pathogen only. This study is the first to provide an understanding on how young grapevine rootstocks inoculated with their ‘home’ and ‘away’ AMF communities would respond to challenge with a black foot pathogen species mixture. Further research is required to understand the mechanistic effect of AMF colonization on the increase of grapevine growth parameters under high black foot disease pressure.

Panax ginseng rusty root rot caused by the Ilyonectria species complex is a devastating disease, and it is one of the main factors contributing to the difficulty in continual cropping. Rusty root rot occurs in all ginseng fields, but little is known about the taxonomy of the fungal pathogen complex, especially Ilyonectria and Ilyonectria -like species. Rusty root rot samples were collected from commercial ginseng cultivation areas of China, and the pathogens were isolated and purified as single spores. Based on the combination analysis of multiple loci (rDNA-ITS, TUB , HIS3 , TEF , ACT , LSU, RPB1 , RPB2 , and SSU) and morphological characteristics, the pathogens causing ginseng rusty root rot were determined. Fungal isolates were obtained from infected roots in 56 locations within main cultivation areas in China. A total of 766 strains were identified as Ilyonectria , Ilyonectria -like and Rhexocercosporidium species, including I. robusta (55.0%), I. communis (21.7%), I. mors-panacis (10.9%), I. pseudodestructans (2.0%), I. changbaiensis (1.3%), I. qitaiheensis (1.3%), Neonectria obtusispora (2.0%), Dactylonectria torresensis (0.5%), D. sp. (0.5%), and R. panacis (1.5%), and four novel species, Thelonectria ginsengicola (1.0%), T. jixiensis (1.0%), T. mulanensis (0.8%) and T. fusongensis (0.5%), with a total of 14 species. As the pathogen present in the highest proportion, I. robusta was the most prevalent and damaging species, unlike the pathogens reported previously. All of the examined strains were proven to cause ginseng rusty root rot. Our results indicate that the taxonomy of the fungal complex associated with ginseng rusty root rot includes Ilyonectria , Ilyonectria -like genera (Dactylonectria , Neonectria , and Thelonectria) and Rhexocercosporidium. [ABSTRACT FROM AUTHOR]

Management of black foot disease (BFD) of grapevines is difficult due to limited control options. Biological control fungi, in particular Trichoderma spp., hold potential as part of integrated management of BFD. Trichoderma atroviride, T. fertile, T. harzianum and T. virens were evaluated in vitro against four common BFD pathogens in South Africa, including Campylocarpon fasciculare, C. pseudofasciculare, Dactylonectria macrodidyma and Ilyonectria liriodendri. Effects of Trichoderma volatile organic and diffusible antifungal compounds (VOCs and DACs) and direct antagonistic effects were determined in Petri dish assays. Pathogen growth inhibition was determined in the VOC and DAC assays. Macro- and microscopic observations of fungus interaction zones were made in dual culture plate assays. Greater BFD pathogen growth inhibition occurred with the DACs than the VOCs. For both classes of compounds, D. macrodidyma was the most sensitive pathogen (100% inhibition by DACs and 65% by VOCs). In some cases, depending on the Trichoderma spp. isolate, growth stimulation occurred for I. liriodendri, C. fasciculare and C. pseudofasciculare. Macroscopically observed Trichoderma and BFD pathogen interactions included total or partial overgrowth, often associated with sporulation of the Trichoderma spp., and arrested growth or the formation of inhibition zones. Microscopic interactions included adhesion of the Trichoderma to pathogen hyphae, pathogen hyphae swelling, malformation and disintegration. In general, in vitro efficacy was isolate-dependent, both for Trichoderma spp. and the BFD pathogen. [ABSTRACT FROM AUTHOR]

Plant roots host diverse microbes that are closely associated with root fitness. Currently, the relationship between microbes and rusty roots of Panax ginseng remains unclear. Here, we described the root-associated microbiome in rusty and healthy ginseng by metagenomic sequencing of 16S rRNA and ITS regions. Being enriched in Diseased-roots (Dr) of ginseng and their rhizosphere soil, the fungus of Ilyonectria, was identified as the most probable cause of the disease after ITS analysis. Meanwhile, an increase of Mortierella was observed in Healthy-roots (Hr). Surprisingly, an enriched Fusarium was found in both Hr and their rhizosphere soil. Besides, in comparison with Hr, decreased relative abundance of Actinomycetales and increased relative abundance of Pseudomonadales was observed in Dr after 16S rRNA analysis. What’s more, we isolated several microorganisms as antagonists that showed strong inhibiting effects on Ilyonectria in plate assays. In field trials, inoculation of Bacillus sp. S-11 displayed apparent suppression effect against Ilyonectria and shifted microbial communities in rhizosphere soil. Our research identified key microbiota involved in rusty roots of P. ginseng and offered potential biocontrol solutions to rusty disease.

(1) Background. An extensive survey of grapevine-sown cover crops and spontaneous weed flora was conducted from 2019 to 2020 in organic vineyards in six European countries (France, Italy, Romania, Slovenia, Spain, Switzerland). Our main objective was to detect and identify the presence of Cylindrocarpon-like asexual morphs species associated with black-foot disease on their roots. (2) Methods. Fungal isolations from root fragments were performed on culture media. Cylindrocarpon-like asexual morph species were identified by analyzing the DNA sequence data of the histone H3 (his3) gene region. In all, 685 plants belonging to different botanical families and genera were analyzed. Cylindrocarpon-like asexual morphs were recovered from 68 plants (9.9% of the total) and approximately 0.97% of the plated root fragments. (3) Results. Three fungal species (Dactylonectria alcacerensis, Dactylonectria torresensis, Ilyonectria robusta) were identified. Dactylonectria torresensis was the most frequent, and was isolated from many cover crop species in all six countries. A principal component analysis with the vineyard variables showed that seasonal temperatures and organic matter soil content correlated positively with Cylindrocarpon-like asexual morphs incidence. (4) Conclusions. The presence of Cylindrocarpon-like asexual morphs on roots of cover crops suggests that they can potentially act as alternative hosts for long-term survival or to increase inoculum levels in vineyard soils.

Host preference of root endophytes of the three European tree species of Norway spruce (Picea abies), common ash (Fraxinus excelsior), and sycamore maple (Acer pseudoplatanus) were investigated in two forest stands near Zurich, Switzerland. The focus was placed on members of the Phialocephala fortinii s.l. (sensu lato)—Acephala applanata species complex (PAC), as well as other dark septate endopyhtes (DSE). PAC species were identified based on 13 microsatellite loci. Eleven PAC species were found, with Phialocephala helvetica, P. europaea being the most frequent. All but cryptic species 12 (CSP12) preferred Norway spruce as a host. Though very rare in general, CSP12 was most frequently isolated from maple roots. Regarding the abundant PAC species, P. helvetica and P. europaea, the preference of spruce as a host was least pronounced in P. europaea, as it was also often isolated from ash and maple. It is the first record of PAC found on common ash (Fraxinus excelsior). Cadophora orchidicola, a close relative of PAC, has frequently been isolated from ash. Various species of the Nectriaceae (Cylindrocarpon spp.) have often been isolated, particularly from maple roots. By comparison, Pezicula spp. (Cryptosporiopsis spp.) was found to be abundant on all three hosts. Phomopsis phaseoli exhibits a clear preference for spruce.

Plant roots host diverse microbes that are closely associated with root fitness. Currently, the relationship between microbes and rusty roots of Panax ginseng remains unclear. Here, we described the root-associated microbiome in rusty and healthy ginseng by metagenomic sequencing of 16S rRNA and ITS regions. Being enriched in Diseased-roots (Dr) of ginseng and their rhizosphere soil, the fungus of Ilyonectria , was identified as the most probable cause of the disease after ITS analysis. Meanwhile, an increase of Mortierella was observed in Healthy-roots (Hr). Surprisingly, an enriched Fusarium was found in both Hr and their rhizosphere soil. Besides, in comparison with Hr, decreased relative abundance of Actinomycetales and increased relative abundance of Pseudomonadales was observed in Dr after 16S rRNA analysis. What's more, we isolated several microorganisms as antagonists that showed strong inhibiting effects on Ilyonectria in plate assays. In field trials, inoculation of Bacillus sp. S-11 displayed apparent suppression effect against Ilyonectria and shifted microbial communities in rhizosphere soil. Our research identified key microbiota involved in rusty roots of P. ginseng and offered potential biocontrol solutions to rusty disease. [ABSTRACT FROM AUTHOR]

Black foot disease, caused by Ilyonectria liriodendri and Dactylonectria macrodidyma, is a significant disease of grapevines both in New Zealand and worldwide. The aim of this study was to determine the pathogenicity of New Zealand I. liriodendri and D. macrodidyma isolates in two grapevine rootstocks as callused and rooted propagation material. Three isolates each of I. liriodendri and D. macrodidyma, all infected callused and root-wounded grapevine rootstock plants (varieties '101–14' and '5C'). Isolates from each species caused high disease incidences and severities at both 1 and 5 cm above the stem base. There were no significant differences in disease incidence or severity between rootstocks '101–14' and '5C'. However, vines arising from callused rootstock had significantly higher disease incidence and severity compared with rooted vines. Conidia caused greater disease incidence and severity compared with chlamydospores and mycelium. A novel threshold propagule experiment with I. liriodendri propagules determined that disease incidence and severity at the stem base were significantly affected by the concentration of the propagules rather than the propagule type. Root dry weights significantly differed between I. liriodendri and D. macrodidyma isolates but not between species. Root dry weights were higher with callused versus rooted vines, with mycelium versus chlamydospores or conidia, and with propagule concentration rather than propagule type. Shoot dry weights were significantly higher for I. liriodendri compared with D. macrodidyma species, rooted versus callused vines and '101–14' compared with '5C' rootstocks. The results of the study has confirmed that both I. liriodendri and D. macrodidyma were capable of infecting grapevines through wounded roots or callused basal ends, indicating that these pathogens are capable of invading grapevines either in nurseries or in vineyards. [ABSTRACT FROM AUTHOR]

Ginseng root is an economically valuable crop in Canada at high risk of yield loss caused by the pathogenic fungus Ilyonectria mors-panacis, formerly known as Cylindrocarpon destructans. While this pathogen has been well-characterized from morphological and genetic perspectives, little is known about the secondary metabolites it produces and their role in pathogenicity. We used an untargeted tandem liquid chromatography-mass spectrometry (LC-MS)-based approach paired with global natural products social molecular networking (GNPS) to compare the metabolite profiles of virulent and avirulent Ilyonectria strains. The ethyl acetate extracts of 22 I. mors-panacis strains and closely related species were analyzed by LC-MS/MS. Principal component analysis of LC-MS features resulted in two distinct groups, which corresponded to virulent and avirulent Ilyonectria strains. Virulent strains produced more types of compounds than the avirulent strains. The previously reported I. mors-panacis antifungal compound radicicol was present. Additionally, a number of related resorcyclic acid lactones (RALs) were putatively identified, namely pochonins and several additional derivatives of radicicol. Pochonins have not been previously reported in Ilyonectria spp. and have documented antimicrobial activity. This research contributes to our understanding of I. mors-panacis natural products and its pathogenic relationship with ginseng.

In the present study, we presented the complete mitochondrial genome (mitogenome) of Ilyonectria sp. The complete mitogenome of Ilypnectria sp. was composed of circular DNA molecules, with a total length of 34, 584 bp. The base composition of this mitogenome is as follows: A (35.31%), T (35.92%), G (15.93%), and C (12.83%). The mitogenome contains 18 protein-coding genes, 2 ribosomal RNA genes (rRNA), and 25 transfer RNA (tRNA) genes. The taxonomic status of the Ilyonectria sp. mitogenome exhibits a closest relationship with Ilyonectria destructans.

Summary. Young grapevine plants with decline and wood necrosis symptoms were collected from vineyards and nurseries in the Apulia and Molise regions, Italy, from 2013 to 2015. Isolations of fungi were prepared from 45 diseased grapevine plants, and the cultures were identified. Several species commonly associated with Petri disease, Botryosphaeria dieback, and black foot disease were isolated. A detailed study was carried out, and 182 isolates resembling Cylindrocarpon-like asexual forms were identified through morphological characterisation and DNA analysis of internal transcribed spacer regions 1 and 2 of the rRNA gene and the partial β-tubulin gene. Dactylonectria torrensensis and Ilyonectria liriodendri were identified based on morphological features and the partial histone 3 gene, so these fungi can be defined as the causal agents of black foot on grapevine for the first time in Italy. Thelonectria blackeriella is also described as a new species, through morphological characterisation and multigenic analysis using sequence data for five loci (large subunit RNA, internal transcribed spacers, β-tubulin, actin, RNA polymerase II subunit 1). This new species was associated with black foot symptoms according to preliminary pathogenicity tests, with representative isolates of each of the three species. Pathogenicity tests showed that these species can cause black streaking in the wood of 1-year-old grapevine rootstock shoots. The identification of D. torresensis, I. liriodendri and T. blackeriella from young grapevine plants and rooted rootstock highlights the importance of black foot disease in Italy, which has previously been overlooked.

Ilyonectria is a weak pathogen known for causing black foot disease in young vines, infecting roots and vascular tissues at the basal end of the rootstock and restricting the movement of water and nutrients. This negatively impacts vine establishment during transplant into the vineyard. Arbuscular mycorrhizal (AM) fungi are symbiotic fungi that associate with most plants and have been shown to mitigate the infection and effect of pathogens. This greenhouse study was designed to determine if the mycorrhizal fungi could mitigate Ilyonectria infection and whether this was dependent on inoculation timing. ‘Riparia gloire’ grapevine rootstocks (Vitis riparia) were infected with Ilyonectria either after AM fungi, at the same time as AM fungi, or to roots that were not inoculated by AM fungi. We measured the abundance using specific markers for both the pathogen and AM fungi. Colonization by AM fungi did not suppress Ilyonectria, but instead increased the abundance of Ilyonectria. Further, mycorrhizal rootstocks did not have enhanced growth effects on physiological parameters when compared to non-mycorrhizal rootstocks. These findings stand in contrast to the general perception that AM fungi provide protection against root pathogens.

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Young grapevine plants with decline and wood necrosis symptoms were collected from vineyards and nurseries in tire Apulia and Molise regions, Italy, from 2013 to 2015. Isolations of fungi were prepared from 45 diseased grapevine plants, and the cultures were identified. Several species commonly associated with Petri disease, Botrvosphaeria dieback, and black foot disease were isolated. A detailed study was carried out, and 182 isolates resembling Cylindrocarpon-like asexual forms were identified through morphological characterisation and DNA analysis of internal transcribed spacer regions 1 and 2 of the rRNA gene and the partial β-tubulin gene. Dactylonec-tria torresensis and Uyonectria liriodendri were identified based on morphological features and the partial histone 3 gene, so these fungi can be defined as the causal agents of black foot on grapevine for the first time in Italy. Thelonectria blackeriella is also described as a new species, through morphological characterisation and multigenic analysis using sequence data for five loci (large subunit RNA, internal transcribed spacers, β-tubulin, actin, RNA polymerase II subunit 1). This new species was associated with black foot symptoms according to preliminary pathogenicity tests, with representative isolates of each of the three species. Pathogenicity tests showed that these species can cause black streaking in the wood of 1-year-old grapevine rootstock shoots. The identification of D. torresensis, 1. liriodendri and T. blackeriella from young grapevine plants and rooted rootstock highlights the importance of black foot disease in Italy, which has previously been overlooked. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare 11 treatment regimes (TR) in grapevine nurseries in order to eradicate trunk pathogens. Grapevine propagation material was subjected to treatments before cold storage, before and after grafting, before planting and after uprooting. Isolations were made from roots, rootstocks and graft unions of uprooted vines. None of the treatments consistently affected the number of certifiable vines produced. TR 1 (benomyl), TR 3 (Sporekill) and TR 4 (Trichoflow) increased root mass. Phaeomoniella chlamydospora was the most frequently isolated pathogen from all plant parts. In general, TR 2, 7, 9 and 11 caused the lowest occurrence of Phaeomoniella. TR 9 consistently reduced the incidence of Phaeoacremonium. Pleurostomophora richardsiae occurred most frequently in graft unions, but treatments were too inconsistent to draw meaningful conclusions. TR 7 (hot water treatment (HWT) of uprooted grapevines) consistently reduced incidences of black foot disease (BFD) pathogens. The highest incidence of Botryosphaeriaceae occurred in graft unions, but all treatments significantly reduced infections. The colonisation of rootstocks and graft unions by Trichoderma was significantly better with TR 4 (Trichoflow). The other Trichoderma treatments (TR 9, 10 and 11) differed from the control treatment only in the graft unions. This is a first report of an integrated strategy covering all the phases of the propagation process, from the moment the nursery receives the propagation material until the dormant vines are removed. TR 9 is recommended for use in nurseries, although HWT of dormant vines is recommended to eradicate BFD pathogens. Benomyl can be replaced by carbendazim when benomyl is no longer available. [ABSTRACT FROM AUTHOR]

Genera with cylindrocarpon-like asexual morphs are important pathogens of various herbaceous and woody plant hosts globally. Recent multi-gene studies of this generic complex indicated that the genus Ilyonectria is paraphyletic. The present study was therefore initiated to re-evaluate the generic status of Ilyonectria and at the same time address some taxonomic irregularities in the genera Cylindrodendrum and Neonectria. Using multi-gene DNA data and morphological comparisons, the genus Dactylonectria is introduced with 10 new combinations, several of which were previously treated in Ilyonectria. Two new species, D. hordeicola and D. pinicola, are also described. Furthermore, one new combination is provided in the genus Cylindrodendrum, and three new combinations in the genus Neonectria, for species previously treated in the genera Acremonium, Cylindrocarpon, Nectria and Neonectria. The aquatic genus Heliscus is reduced to synonymy under Neonectria.

Black-foot is one of the most destructive grapevine trunk diseases in nurseries and young vineyards, causing necrotic root lesions, wood necrosis of the rootstock base, and a gradual decline and death of grapevines. Causal agents of the disease are included into the genera Campylocarpon, “Cylindrocarpon”, Cylindrocladiella and Ilyonectria. Recent taxonomical studies of Neonectria and related genera with “Cylindrocarpon”-like anamorphs based on morphological and phylogenetic studies, divided Neonectria into five genera. Thus, the current taxonomical position and classification of the causal agents of black-foot disease, mainly “Cylindrocarpon”/Ilyonectria, comprises one of the main topics of this review. The review also provides an update on geographical distribution, epidemiology and management strategies of the disease.

Genera with cylindrocarpon-like asexual morphs are important pathogens of various herbaceous and woody plant hosts globally. Recent multi-gene studies of this generic complex indicated that the genus Ilyonectria is paraphyletic. The present study was therefore initiated to re-evaluate the generic status of Ilyonectria and at the same time address some taxonomic irregularities in the genera Cylindrodendrum and Neonectria. Using multi-gene DNA data and morphological comparisons, the genus Dactylonectria is introduced with 10 new combinations, several of which were previously treated in Ilyonectria. Two new species, D. hordeicola and D. pinicola, are also described. Furthermore, one new combination is provided in the genus Cylindrodendrum, and three new combinations in the genus Neonectria, for species previously treated in the genera Acremonium, Cylindrocarpon, Nectria and Neonectria. The aquatic genus Heliscus is reduced to synonymy under Neonectria. [ABSTRACT FROM AUTHOR]

Forty-two kiwifruit orchards from Rize and Samsun provinces (Black Sea region, Turkey) exhibiting symptoms of root rot disease were examined between 2009 and 2010. Twenty-four fungal isolates recovered from affected roots were included in this study. Morphological characteristics of all isolates were recorded on potato dextrose agar, malt extract agar and Spezieller Nährstoffarmer agar. The effect of temperature on radial colony growth was also evaluated at 5, 10, 15, 20, 25, 30, and 35 °C. Histone H3 gene (HIS) was amplified with primers CYLH3F and CYLH3R and the amplified fragments were sequenced. The HIS phylogeny grouped all the isolates into six well-supported clades which were in agreement with phenotypical characteristics. Isolates were identified as ' Cylindrocarpon' pauciseptatum, Cylindrocladiella parva, Ilyonectria liriodendri, I. torresensis, I. robusta and I. europaea, I. liriodendri being the most frequent species . All of them are reported for the first time on kiwifruit in Turkey, with the exception of I. liriodendri. Pathogenicity tests with selected isolates showed that 10 out of 11 isolates tested were able to induce typical root rot disease symptoms, affecting plant development and leading to the death of some plants. This study shows the high diversity of root rot pathogens found in kiwifruit trees in the Black Sea region of Turkey, being the first step towards a better understanding and management of the disease in local conditions. [ABSTRACT FROM AUTHOR]