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Botryosphaeriaceae are fungi involved in the decay of various woody species, including the grapevine, leading to significant production losses. This fungal family is largely ubiquitous, and seven species of Botryosphaeriaceae have been identified in French vineyards, with variable levels of aggressiveness, both in vitro and in planta. Mycoviruses can impact the life traits of their fungal hosts, including aggressiveness, and are one of the factors influencing fungal pathogenicity. In this study, the RNA mycovirome of fifteen Botryosphaeriaceae isolates was characterized through the high-throughput sequencing of double-stranded RNA preparations from the respective samples. Eight mycoviruses were detected, including three potential novel species in the Narnaviridae family, as well as in the proposed Mycobunyaviridae and Fusagraviridae families. A large collection of Botryosphaeriaceae isolates was screened using RT-PCR assays specific for 20 Botryosphaeriaceae-infecting mycoviruses. Among the mycoviruses detected, some appeared to be specialists within a single host species, while others infected isolates belonging to multiple Botryosphaeriaceae species. This screening allowed us to conclude that one-third of the Botryosphaeriaceae isolates were infected by at least one mycovirus, and a significant proportion of isolates (43.5%) were found to be coinfected by several viruses, with very complex RNA mycoviromes for some N. parvum isolates. [ABSTRACT FROM AUTHOR]

Decline phenomena of shrub species such as Quercus coccifera and Retama raetam have occurred throughout Tunisian forests since 2012. These evergreen shrubs have long been regarded for their medicinal and ecological interests. Therefore, their preservation as valuable forest resources is of great interest. However, information regarding aetiology of this disease is still scarce. Hence, the aim of this study was to identify and characterize the causal agents associated with disease symptoms in two Tunisian forests. Thirty‐eight isolates were obtained from symptomatic Q. coccifera and R. raetam twigs. Morphological characterization and phylogenetic analysis of the internal transcribed spacer (ITS) region of the nuclear ribosomal RNA gene cluster and partial sequence of the translation elongation factor 1‐alpha gene (tef1‐α) allowed the identification of three Diplodia species namely Diplodia africana, D. seriata and D. pseudoseriata. Our findings revealed that the incidence of Diplodia species was significantly correlated to the altitude, the temperature and the rainfall. Pathogenicity test showed that all Diplodia isolates are pathogenic. However, D. africana revealed to be the most aggressive species toward R. raetam. These findings were the first record of D. seriata as fungal pathogen associated with Q. coccifera dieback and D. pseudoseriata and D. africana on R. raetam in Tunisia. [ABSTRACT FROM AUTHOR]

Botryosphaeriaceae are fungi involved in the decay of various woody species, including the grapevine, leading to significant production losses. This fungal family is largely ubiquitous, and seven species of Botryosphaeriaceae have been identified in French vineyards, with variable levels of aggressiveness, both in vitro and in planta. Mycoviruses can impact the life traits of their fungal hosts, including aggressiveness, and are one of the factors influencing fungal pathogenicity. In this study, the RNA mycovirome of fifteen Botryosphaeriaceae isolates was characterized through the high-throughput sequencing of double-stranded RNA preparations from the respective samples. Eight mycoviruses were detected, including three potential novel species in the Narnaviridae family, as well as in the proposed Mycobunyaviridae and Fusagraviridae families. A large collection of Botryosphaeriaceae isolates was screened using RT-PCR assays specific for 20 Botryosphaeriaceae-infecting mycoviruses. Among the mycoviruses detected, some appeared to be specialists within a single host species, while others infected isolates belonging to multiple Botryosphaeriaceae species. This screening allowed us to conclude that one-third of the Botryosphaeriaceae isolates were infected by at least one mycovirus, and a significant proportion of isolates (43.5%) were found to be coinfected by several viruses, with very complex RNA mycoviromes for some N. parvum isolates.

Black canker, caused by fungi of the genus Diplodia, poses an increasing threat to pome fruit production in Germany. In order to determine the spread of the disease in Germany, 423 bark samples with suspicious symptoms from all federal states were examined in a non-representative monitoring. In 62% of the samples examined, fungi of the genus Diplodia were isolated, with the species D. bulgarica dominating the Diplodia species spectrum with 56.6%, followed by D. seriata with 28.3%. D. malorum (7.8%), D. mutila (4.9%), D. juglandis (1.6%) and D. intermedia (0.8%), on the other hand, took up only a small part of the Diplodia species spectrum, with the latter two species being first records on apple in Germany. [ABSTRACT FROM AUTHOR]

Der Schwarze Rindenbrand, der von Pilzen aus der Gattung Diplodia hervorgerufen wird, stellt eine zunehmende Bedrohung für den Kernobstanbau in Deutschland dar. Um die Verbreitung der Erkrankung im Bundesgebiet zu ermitteln, wurden in einem nicht repräsentativen Monitoring 423 Rindenproben mit verdächtigen Symptomen aus allen Bundesländern untersucht. In 62 % der untersuchten Proben waren Pilze aus der Gattung Diplodia zu isolieren, wobei die Art D. bulgarica mit 56,6 %, gefolgt von D. seriata mit 28,3 % das Diplodia-Artenspektrum dominiert haben. D. malorum (7,8 %), D. mutila (4,9 %), D. juglandis (1,6 %) und D. intermedia (0,8 %) traten dagegen relativ selten auf, wobei die beiden letztgenannten Arten Erstnachweise an Apfel in Deutschland sind.

In Bazhong City, Sichuan Province, China, top dieback symptoms were found on many pine trees (Pinus thunbergii Parl). The tips of old needles first turned grayish-green and then developed into brown bands in the field. Phylogenetic analysis of concatenated ITS and EF1-α indicated the pathogen of this dieback disease as Diplodia neojuniperi. Additionally, effects of temperature, pH and medium on the mycelial growth were also characterized. The most favorable temperature and pH level for mycelial growth are 25°C and 8, respectively. The optimal medium for mycelial growth is PDA medium. To our knowledge, this is the first report of D. neojuniperi causes Diplodia top dieback on Pinus thunbergii. Our results provide fundamental information for monitoring and preventing such disease in the future. [ABSTRACT FROM AUTHOR]

Dieback and canker disease caused by species of Botryosphaeriales affect the productivity of pome fruit orchards. In this study, we evaluated the efficacy of fungicides and biofungicide for controlling canker and dieback diseases in apple and pear using in vitro and field trials. Isolates of Diplodia seriata, D. mutila, and Dothiorella omnivora from apple, and of D. seriata and Aplosporella aquifolii from pear were used. Cercobin® (thiophanate-methyl), followed by Bellis® (pyraclostrobin + boscalid), and Nativo® (tebuconazole + trifloxystrobin) inhibited mycelial growth, conidial germination and pycnidia formation in vitro in all fungal isolates. T. harzianum produced mycelial growth inhibition and mycoparasitism in dual culture assays. Thiophanate-methyl and T. harzianum fully inhibited pycnidia production, while pyraclostrobin + boscalid and tebuconazole + trifloxystrobin were most effective against conidia germination. In the orchard assays, protective sprays of the fungicides on pruning wounds reduced incidence by up to 20%, while T. harzianum and tebuconazole + trifloxystrobin reduced the lesion severity up 37 and 41%, respectively. This study represents the first evaluation of fungicides and biofungicide effectiveness for the control of canker and dieback diseases of apples and pears in Argentina. [ABSTRACT FROM AUTHOR]

Olive production has expanded strongly in the last twenty years in Uruguay. In this study, a collection of 37 Botryosphaeriaceae isolates obtained from stem canker and fruit rot symptoms in olive trees of six cultivars from 14 orchards throughout the country were characterized. Based on phylogenetic analysis of ITS and TEF‐1α gene regions and phenotypical characteristics, eight species belonging to the genera Botryosphaeria (41%), Neofusicoccum (51%) and less frequently to Diplodia (8%) were identified. The recognized species were B. wangensis (n = 11), N. cryptoaustrale (n = 9), N. luteum (n = 7), B. dothidea (n = 4), N. occulatum (n = 2), D. seriata (n = 2), N. australe (n = 1) and D. mutila (n = 1). Isolates of all Botryosphaeriaceae species were able to cause typical necrotic lesions on inoculated olive stems of Arbequina cultivar under laboratory conditions, but those belonging to Neofusicoccum genus were significantly more aggressive. Five of the eight species found in this study were previously reported affecting other fruit and forestry trees in Uruguay; thus, further epidemiologic studies and management programmes should be developed considering all the Botryosphaeriaceae hosts, especially those cultivated in proximity. Also, we present B. wangensis, N. cryptoaustale, N. occulatum and D. mutila species as new records to olive worldwide. [ABSTRACT FROM AUTHOR]

English walnut (Juglans regia) has become an important crop in Chile, representing 11.5% of the total area of fruit trees, surpassed only by grapevine. As the Chilean walnut industry rapidly expands, young orchards are at risk from the emergence of new fungal diseases. Botryosphaeriaceae and Diaporthaceae fungi have been recognized as main causes of wood diseases in walnut, with symptoms of dieback, canker, and blight. In winter 2017, samples were collected from different orchards in Valparaíso and Maule regions. Fungal isolates recovered were cultured, characterized morphologically, and identified using DNA sequence analyses. Three species (Neofusicoccum parvum, Diplodia mutila, Diplodia seriata) were characterized in Botryosphaeriaceae and two (Diaporthe cynaroidis, Diaporthe australafricana) in Diaporthaceae. Pathogenicity tests showed that N. parvum was the most aggressive species to walnut. This study confirmed the presence of pathogenic Botryosphaeriaceae and Diaporthaceae in J. regia that should be considered an increasing risk for the growing Chilean walnut industry. [ABSTRACT FROM AUTHOR]

English walnut (Juglans regia) has become an important crop in Chile, representing 11.5% of the total area of fruit trees, surpassed only by grapevine. As the Chilean walnut industry rapidly expands, young orchards are at risk from the emergence of new fungal diseases. Botryosphaeriaceae and Diaporthaceae fungi have been recognized as main causes of wood diseases in walnut, with symptoms of dieback, canker, and blight. In winter 2017, samples were collected from different orchards in Valparaíso and Maule regions. Fungal isolates recovered were cultured, characterized morphologically, and identified using DNA sequence analyses. Three species (Neofusicoccum parvum, Diplodia mutila, Diplodia seriata) were characterized in Botryosphaeriaceae and two (Diaporthe cynaroidis, Diaporthe australafricana) in Diaporthaceae. Pathogenicity tests showed that N. parvum was the most aggressive species to walnut. This study confirmed the presence of pathogenic Botryosphaeriaceae and Diaporthaceae in J. regia that should be considered an increasing risk for the growing Chilean walnut industry.

Interaction among nitrogen fertilization using bovine manure, poultry manure, Jatropha curcas seed cake and urea, and the diseases Ramularia leaf spot (RLS) and Boll rot (BR), caused by Ramulariopsis pseudoglycines and Diplodia gossypina, respectively, in cotton plants (Gossypium hirsutum L.), was studied under field conditions. Intensity (incidence and severity in percentage) of RLS and incidence (%) of BR were evaluated over time, starting in reproductive stage B1 (first visible flower bud). A randomized complete block design with a 4x4 factorial arrangement was used (fertilizers x doses), totaling 16 treatments with four replications. Disease progress was analyzed with the nonlinear Logistic and Gompertz models, obtaining the epidemiological parameters amount of initial disease (Y0) and progress rate (r). Plants fertilized with 50 kg N ha-1, presented an incidence twice greater than those obtained with other fertilizers. The Logistic model better fits RLS, but no model could represent BR. Only the epidemiological parameters of RLS were affected differently in this experiment compared to BR disease. The possible role of organic and inorganic nitrogen fertilization in the RLS and BR management is discussed. [ABSTRACT FROM AUTHOR]

Apple fruit cv. Golden Delicious symptoms of rot were collected from storage in the area of Eğirdir district of Isparta province, in Turkey. Based on morphology and phylogeny of DNA sequence data for the internal transcribed spacer (ITS) rDNA region, the isolated pathogen was identified as Diplodia bulgarica. This is the first description of D. bulgarica causing postharvest fruit rot on Malus domestica cv. Golden Delicious in Turkey and worldwide. [ABSTRACT FROM AUTHOR]

Phoenix dactylifera L. is an economically and aesthetically important tree in the southwestern US. Approximately 4900 ha of dates are commercially grown for its edible fruit in the US, including about 1600 ha in the Yuma area and the Hyder Valley of Arizona (USDA, 2023). In October 2022, a severe rot was observed on three date palms in the Phoenix Metropolitan area. Early symptoms were brown spots that turned to a black scorch appearance extending along the leaf base and rachis, leading to the lower fronds' wilting, drying, and folding. As the disease progressed upwards, the terminal bud became necrotic and eventually collapsed. Isolation from the necrotic leaf lesions on a potato dextrose agar (PDA) consistently yielded a fast-growing fungus that was initially white with abundant fluffy aerial mycelium, which gradually turned dark olivaceous after growing at 22-25oC under 12 h light for a week. Pycnidial conidiomata formed on pine needles in a water agar were black and globose. Conidiogenous cells were hyaline and cylindrical. The conidia exhibited a thick-walled, ovoid to ellipsoid morphology, initially appearing hyaline and aseptate and transitioned to 1-septate with a dark brown, striated appearance, measuring 19.6 to 23.0 μm x 10.3 to 12.2 µm (n = 20). For molecular identification, genomic DNA was extracted from the mycelia of two isolates. Partial DNA sequences of the internal transcribed spacer (ITS) region of rDNA and β-tubulin (TUB) gene were amplified and sequenced using primers ITS5/ITS4 (White et al. 1990) and Bt2a/Bt2b (Glass and Donaldson 1995). The resulting sequences of ITS (PP346666) and TUB (PP372690) were deposited in the GenBank. A BLASTn search of ITS and TUB sequences revealed a 99 to 100% similarity with the sequences (JX456475, KF766198, and OK338070) of Neodeightonia phoenicum strains causing palm rot in Greece (Ligoxigakis et al. 2013), leaf spot on pygmy date palm in China (Zhang and Song 2022), and an ex-type CBS 122528 culture. Based on these morphological and molecular data, the fungus was identified as N. phoenicum. A pathogenicity test was conducted twice in a greenhouse (daily temperatures:18 ~ 30 oC, relative humidity: 45% ~ 95%) on 4 healthy 1-year-old date palm plants. The petioles of 3 older leaves per plant were wounded by pricking the epidermis of the leaf with a needle (ca 20 pricks per petiole) and inoculated with agar discs from a 4-day-old PDA culture of the fungus. The control consisted of 4 mock-inoculated plants by placing plain PDA on the wounds of leaf petioles. Five weeks after inoculation, all the inoculated leaves showed symptoms of black scorch, petiole rot, and leaf necrosis, which were the same as those symptoms observed on the original diseased trees, while the controls did not show any symptoms. The fungus was re-isolated and confirmed as N. phoenicum by morphology. N. phoenicum has been reported to cause leaf spot, shoots blights, stalk and root rots as well as black scorch on different palm species all over the world. However, to our knowledge, this is the first report of N. phoenicum causing black scorch and rot disease in Arizona. The possible spread of N. phoenicum could have a significant economic impact and requires immediate attention through suitable disease management initiatives.

An increase in cork oak diseases caused by Biscogniauxia mediterranea and Diplodia corticola has been reported in the last decade. Due to the high socio-economic and ecologic importance of this plant species in theMediterranean Basin, the search for preventive or treatment measures to control these diseases is an urgent need. Fungal endophyteswere recovered fromcork oak treeswith different disease severity levels, using culture-dependent methods. The results showed a higher number of potential pathogens than beneficial fungi such as cork oak endophytes, even in healthy plants. The antagonist potential of a selection of eight cork oak fungal endophytes was tested against B. mediterranea and D. corticola by dual-plate assays. The tested endophytes were more efficient in inhibiting D. corticola than B. mediterranea growth, but Simplicillium aogashimaense, Fimetariella rabenhorstii, Chaetomium sp. and Alternaria alternata revealed a high potential to inhibit the growth of both. Simplicillium aogashimaense caused macroscopic and microscopic mycelial/hyphal deformations and presented promising results in controlling both phytopathogens' growth in vitro. The evaluation of the antagonistic potential of non-volatile and volatile compounds also revealed that A. alternata compounds could be further explored for inhibiting both pathogens. These findings provide valuable knowledge that can be further explored in in vivo assays to find a suitable biocontrol agent for these cork oak diseases. [ABSTRACT FROM AUTHOR]

Fungi in the family Botryosphaeriaceae are known as pathogens of diverse woody hosts, including forest tree species. Although, several of these fungi have been described in different forest hosts in Portugal, their diversity and distribution is still poorly understood. A survey was conducted across the country to identify Botryosphaeriaceae species associated with the main forest tree species in Portugal, Quercus suber, Eucalyptus globulus and Pinus pinaster. Additionally, a meta-analysis was performed to compile and organize all records known from Portugal. From this meta-analysis, 22 different Botryosphaeriaceae species were reported and 40 different plant hosts were recorded in several studies from agricultural crops to ornamental and forest species. A total of 105 host-pathogen interactions were identified. In the national survey, 12 Botryosphaeriaceae species were identified, with Diplodia corticola being the most frequent. Diplodia insularis, Diplodia pyri, Dothiorella plurivora and Dothiorella yunnana are reported for the first time in Portugal. Of the 23 different host-fungus associations identified, 10 are also recognised as new hosts. Artificial inoculation tests confirmed the pathogenicity of all species, except Dothiorella iberica, Dothiorella plurivora and Dothiorella yunnana, which are regarded as weakly or non-pathogenic to the hosts tested. Pathogenicity tests revealed the host-jump potential of some species, showing high susceptibility of Q. suber to Neofusicoccum parvum and N. eucalyptorum and of P. pinaster to D. corticola. Our results show that Botryosphaeriaceae species have a widespread distribution across the country, however some species such as D. corticola, D. sapinea and N. eucalyptorum exhibit a distribution that overlaps the distribution of their preferred hosts. [ABSTRACT FROM AUTHOR]

This study represents the first survey studying the occurrence, genetic diversity, and pathogenicity of Botryosphaeriaceae species associated with symptomatic citrus species in citrus-production areas in five European countries. Based on morphological features and phylogenetic analyses of internal transcribed spacer (ITS) of nuclear ribosomal DNA (nrDNA), translation elongation factor 1-alpha (TEF1) and β-tubulin (TUB2) genes, nine species were identified as belonging to the genera Diplodia, Dothiorella, Lasiodiplodia, and Neofusicoccum. Isolates of Neofusicoccum parvum and Diplodia pseudoseriata were the most frequently detected, while Dothiorella viticola had the widest distribution, occurring in four of the five countries sampled. Representative isolates of the nine Botryosphaeriaceae species used in the pathogenicity tests caused similar symptoms to those observed in nature. Isolates assayed were all re-isolated, thereby fulfilling Koch’s postulates. Isolates of Diplodia pseudoseriata and Diplodia olivarum are recorded for the first time on citrus and all species found in our study, except N. parvum, are reported for the first time on citrus in Europe.

Diplodia seriata is a polyphagous and widespread pathogen that infects trunks, shoots, fruit and leaves of apple plants. Fungicides applied in integrated pest management programmes can act against D. seriata. However, introduction of scabresistant apple cultivars and the consequent reduction in fungicide applications under low input disease management may increase the incidence of disease caused by D. seriata. Despite potential outbreaks of trunk canker, no fast and reproducible protocols for artificial inoculation of D. seriata and fungicide efficacy tests are available for apple plants. In this study, protocols for mycelium plug- and conidium suspensioninoculation of apple stems and shoots were optimised; canker disease assessments were carried out on potted apple plants under greenhouse conditions and coupled with D. seriata DNA quantification with quantitative PCR (qPCR). Efficacy tests of commercial fungicides showed that captan, dithianon and fluazinam inhibited D. seriata mycelium growth and conidium viability in vitro, while penconazole and ziram did not. However, dithianon spray applications did not reduce trunk canker severity and amount of D. seriata DNA in artificially inoculated plants under greenhouse conditions. This optimised protocol for fast and precise assessment of fungicide efficacy is suitable for further investigating the effects of other fungicides against D. seriata. [ABSTRACT FROM AUTHOR]

Disease emergence in northern and boreal forests has been mostly due to tree-pathogen encounters lacking a co-evolutionary past. However, outbreaks involving novel interactions of the host or the pathogen with the environment have been less well documented. Following an increase of records in Northern Europe, the first large outbreak of Diplodia sapinea on Pinus sylvestris was discovered in Sweden in 2016. By reconstructing the development of the epidemic, we found that the attacks started approx. 10 years back from several isolated trees in the stand and ended up affecting almost 90% of the trees in 2016. Limited damage was observed in other plantations in the surroundings of the affected stand, pointing to a new introduced pathogen as the cause of the outbreak. Nevertheless, no genetic differences based on SSR markers were found between isolates of the outbreak area and other Swedish isolates predating the outbreak or from other populations in Europe and Asia Minor. On a temporal scale, we saw that warm May and June temperatures were associated with higher damage and low tree growth, while cold and rainy conditions seemed to favor growth and deter disease. At a spatial scale, we saw that spread occurred predominantly in the SW aspect-area of the stand. Within that area and based on tree-ring and isotope (δ13C) analyses, we saw that disease occurred on trees that over the years had shown a lower water-use efficiency (WUE). Spore traps showed that highly infected trees were those producing the largest amount of inoculum. D. sapinea impaired latewood growth and reduced C reserves in needles and branches. D. sapinea attacks can cause serious economic damage by killing new shoots, disrupting the crown, and affecting the quality of stems. Our results show that D. sapinea has no limitations in becoming a serious pathogen in Northern Europe. Management should focus on reducing inoculum, especially since climate change may bring more favorable conditions for this pathogen. Seedlings for planting should be carefully inspected as D. sapinea may be present in a latent stage in asymptomatic tissues. [ABSTRACT FROM AUTHOR]

A total of 252 aerial spore samples from the provinces of Quebec and Ontario were obtained during an extensive research programme focusing on aerobiology of fungal spores. Samples were collected on 95 sticky rods from rotary arm spore collectors and 157 filters from passive rain collectors. DNA from samples was PCR-amplified for fungal ribosomal ITS and sequenced using High Throughput Sequencing (HTS) methods. After bioinformatics analysis of DNA sequences, the presence of Diplodia corticola, an emerging tree pathogen in North America, was observed. In total, 313 DNA sequence reads from aerial spores of D. corticola were found in the Illumina data set, and 199 DNA sequence reads were obtained from the Ion Torrent data set. DNA of D. corticola was found in 16 of the 32 sampled sites, always less than 10 reads per site, with the exception of three sites - Quebec City, Aylmer and Ottawa - where 287, 125 and 73 DNA reads, respectively, were detected. This is not a first report of the presence of D. corticola causing a tree disease in Canada as symptomatic trees have not been identified. Typically, like many other species of the Botryosphaeriaceae, this fungal pathogen is believed to be an opportunistic plant endophyte capable of living asymptomatically for several years before showing up as a pathogen when conducive conditions arise. Its presence as singletons in nearly half the sampled sites in Quebec and Ontario may be the result of long-distance spore dispersal originating from known infected sites in Massachusetts, Maine and other unknown sites in the north-eastern USA. However, its much higher read counts in three sites may indicate the possibility of a few trees being asymptomatically infected and spreading conidia locally. [ABSTRACT FROM AUTHOR]

Cryptic species are common in Diplodia , a genus that includes some well-known and economically important plant pathogens. Thus, species delimitation has been based on the phylogenetic species recognition approach using multigene genealogies. We assessed the potential of mating type ( MAT ) genes sequences as phylogenetic markers for species delimitation in the genus Diplodia . A PCR-based mating type diagnostic assay was developed that allowed amplification and sequencing of the MAT1-1-1 and MAT1-2-1 genes, and determination of the mating strategies used by different species. All species tested were shown to be heterothallic. Phylogenetic analyses were performed on both MAT genes and also, for comparative purposes, on concatenated sequences of the ribosomal internal transcribed spacer (ITS), translation elongation factor 1-alpha ( tef1-α ) and beta-tubulin ( tub2 ). Individual phylogenies based on MAT genes clearly differentiated all species analysed and agree with the results obtained with the commonly used multilocus phylogenetic analysis approach. However, MAT genes genealogies were superior to multigene genealogies in resolving closely related cryptic species. The phylogenetic informativeness of each locus was evaluated revealing that MAT genes were the most informative loci followed by tef1-α . Hence, MAT genes can be successfully used to establish species boundaries in the genus Diplodia . [ABSTRACT FROM AUTHOR]

The existence of a latent stage within host tissue of the pine pathogens Fusarium circinatum and Diplodia sapinea, the causal agents of pitch canker and shoot blight disease respectively, has previously been cited. However, studies on this cryptic phase in each disease lifecycle has only been focused on the host aerial parts but not on the roots. Therefore, our objective was to analyze the presence of both pathogens in roots of non-symptomatic mature trees in plantations where the pathogens are known to be causing canker symptoms. For that, we sampled roots from ten non-symptomatic and ten symptomatic trees in three Pinus radiata and one Pinus pinaster plantations in Basque Country, Spain. Both pathogens were isolated from roots of non-symptomatic trees in a higher frequency than from roots of symptomatic trees, 23.3% and 6.6% respectively for D. sapinea and 16.6% and 3.3% respectively for F. circinatum. Neither pathogens was detected in the P. pinaster plantation. The two pathogens were never isolated from the same tree. A high molecular variability was observed for D. sapinea isolates with six different haplotypes and two mating types for the eleven characterized isolates, but only one haplotype and mating type was found for F. circinatum, with all isolates of both fungi being proved pathogenic. These results evidence the importance root infection may have in the disease lifecycle and, therefore, disease management. [ABSTRACT FROM AUTHOR]

The fungus Stenocarpella maydis (Berk.) B. Sutton, causal agent of Diplodia ear rot, is a prevalent com (Zea mays L.) pathogen in the United States. Although S. maydis reduces grain quality, causes yield loss, and can produce mycotoxins in some countries, few studies have examined its biology and genetic diversity. We analyzed the genetic diversity of 174 S. maydis isolates sampled across the major com production areas in the United States using nine different microsatellites. In all, 55 unique multilocus genotypes (MLG) were observed out of the 174 S. maydis isolates tested. After conducting a Bayesian clustering analysis by STRUCTURE, it was observed that the most probable number of genetic groups was two; however, no separation by their geographical location was identified. According to the minimum spanning network, the S. maydis population is linked across geographic regions of the United States but also contains private genotypes. Temporal diversity in the inoculum source was also observed at one location across 4 years. The haploid stage of S. maydis was confirmed and both mating type genes were amplified among selected isolates with unique MLG. We theorize that, although S. maydis is primarily an asexual fungus, sporadic cryptic recombination may occur, which could contribute to the genetic diversity observed in this study. [ABSTRACT FROM AUTHOR]

Stem-end-rot (SER), caused by Lasiodiplodia theobromae or Diaporthe citri, is an important postharvest disease in humid and warm citrus growing areas, such as the Northwestern region of Argentina. The commercial control of SER has been accomplished by applications of the systemic fungicide carbendazim (CARB). However, alternative chemicals for this fungicide are needed due to increasing restrictive regulations in overseas markets. The aim of this work was to evaluate the effectiveness of conventional and reduced-risk postharvest fungicides to control SER. In vitro tests show that L. theobromae was more resistant to fungicides than D. citri . In trials using artificially inoculated lemons, SER caused by D. citri (Phomopsis SER) was controlled by the fungicides evaluated. The conventional fungicides imazalil and thiabendazole (TBZ) were the most effective chemicals to control SER caused by L. theobromae (Diplodia SER), while other fungicides, as fludioxanil, azoxystrobin, pyrimetanil and propiconazole, were not effective. The best control of Diplodia SER was obtained by immersion for 60 s in 2000 mg/L of TBZ at pH 5 and 20 °C. In this condition, TBZ-residue loading on lemons was 3.0 mg-L −1 , which did not exceed the allowed maximum residue levels. TBZ applied in lemon commercial treatments is the best option to reduce SER caused by both pathogens. At this time, this is the unique suitable alternative to replace CARB treatment in Argentinean packinghouses. [ABSTRACT FROM AUTHOR]

Pine nuts are non-wood forest products (NWFP) with a constantly growing market notwithstanding a series of phytosanitary issues and related trade problems. The aim of this paper is to review the literature on the relationship between phytosanitary problems and trade development. Production and trade of pine nuts in Mediterranean Europe have been negatively affected by the spreading of Diplodia sapinea (a fungus) associated with an adventive insect Leptoglossus occidentalis (fungal vector), with impacts on forest management, production and profitability and thus in value chain organization. Reduced availability of domestic production in markets with a growing demand has stimulated the import of pine nuts. China has become a leading exporter of pine nuts, but its export is affected by a symptom caused by the nuts of some pine species: ‘pine nut syndrome’ (PNS). Most of the studies mentioned in the literature review concern PNS occurrence associated with the nuts of Pinus armandii. We highlight the need for a comprehensive and interdisciplinary approach to the analysis of the pine nuts value chain organization, where research on food properties and clinical toxicology may be connected to breeding and forest management, forest pathology and entomology, and trade development. [ABSTRACT FROM AUTHOR]

Grapevine Trunk Diseases (GTD) are of great importance worldwide, including Hungary, a Center European country with long wine producing history. Several GTD pathogens have been described till now in Europe, but only a few from Hungary. The presence of a GTD pathogen in the vine does not necessarily result in the immediate appearance of disease symptoms, and information on the importance of environmental factors related to disease incidence are still limited. The aim of this research was to assess the occurrence of GTD in the Tokaj Wine Region, and to determine the biotic and abiotic factors influencing disease incidence. Five vineyards within 15 km radius - each with different topology, soil types, varieties and age - were studied for three consecutive years (2013 - 2015). The incidence of GTD-infection was determined every year for each vineyard. Diplodia seriata was isolated with incidence ranging from 50 to 100%, while Diaporthe spp. were the only other - minor - GTD pathogen found. Topology and soil type appeared to be major abiotic factors affecting incidence of GTD symptom. Disease incidence was also positively correlating with the age of the vineyards, and it was in fact found to be the definitive biotic factor regarding incidence. In contrast, D. seriata infection rate appeared unrelated to disease incidence or to any of the biotic or abiotic factors investigated. [ABSTRACT FROM AUTHOR]

As a result of the increasing economic impact of grapevine trunk diseases on viticulture worldwide, efficient and viable control strategies are urgently needed. However, understanding both plant-pathogen interactions and plant physiological changes related to these diseases is fundamental to such an achievement. In this study, we analyzed the effect of inoculation with the Botryosphaeria dieback fungal agents, Neofusicoccum parvum and Diplodia seriata, with and without inflorescence removal at the onset of G stage (separated clusters), I stage (flowering) and M stage (veraison). A measure of lesion size and real-time reverse-transcription polymerase chain reaction-based analysis were carried out. The results clearly show the importance of inflorescences in the development of lesions associated with Botryosphaeria dieback pathogens inoculated on green stems of adult vines, especially at the onset of flowering. At flowering, the biggest necroses were observed with the inflorescences present, as well as an activation of the studied defense responses. Thus, an ineffective response to the pathogen could be consistent with a possible metabolic reprogramming linked to the host phenophase. [ABSTRACT FROM AUTHOR]

Botryosphaeriaceae species are important pathogens of grapevines so the effect of environmental conditions on sporulation from naturally infected Sauvignon blanc grapevines in two Marlborough vineyards was studied. Shoot lesions characteristic of Botryosphaeriaceae infection were marked on 24 grapevines in each vineyard for observation between September 2014 and April 2015. Pycnidia on the lesions oozed conidia during or soon after rainfall on five occasions at maximum air temperatures of 8.4-19.9°C and relative humidities of 77-94.7%. Microscopic observation of the ooze showed conidia characteristic of either Neofusicoccum or Diplodia species in 67% and 50% of samples from Vineyard A and B, respectively. Sixtynine colonies characteristic of Botryosphaeriaeae species were recovered after plating of conidial ooze and identified by DNA analysis as Diplodia mutila (39.1%), Neofusicoccum australe (30.4%), N. parvum (14.5%), N. luteum (5.8%), D. seriata (7.2%) and N. ribis (3.0%). All species have been reported previously as grapevine pathogens in New Zealand. [ABSTRACT FROM AUTHOR]

After the ban on sodium arsenite, waste management alternatives to the prevalent burning method, such as the hygienization and biodegradation in solid phase by composting, are required for the pruned material from grapevines affected by various fungi. In this work the dynamics of a fungus associated with vine decay ( Diplodia seriata ) during the composting process of a mixture of laying hen manure and vine pruning waste (2:1 w/w) have been investigated in an open pile and a discontinuous closed biodigester. Through the optimization of the various physical–chemical parameters, hygienization of the infected waste materials was attained, yielding class-A organo-mineral fertilizers. Nevertheless, important differences in the efficiency of each system were observed: whereas in the open pile it took 10 days to control D. seriata and 35 additional composting days to achieve full inactivation, in the discontinuous biodigester the fungus was entirely inactivated within the first 3–7 days. Finally, the impact of seasonal variability was assessed and summer temperatures shown to have greater significance in the open pile. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the production and germination of Stenocarpella maydis pycnidiospores under in vitro conditions as affected by substrate composition (sorghum, wheat, black oat or barley), light regime (continuous dark, 12-h light dark-1 or continuous light conditions), and incubation temperature (21, 24, 27, 30 or 33ºC). Each substrate (20 g of grain) was soaked in 100 mL of water for 24h and sterilized twice for 20 min at 127ºC. Three plugs (5 mm diameter) of a single-spored culture of S. maydis were used as inocula for each substrate. Assessments of pycnidiospore production per gram of grain and percent germination were made 14 days after inoculation. Barley, black oat or wheat grains were the best substrates for the mass production of S. maydis pycnidiospores and the maintenance of high germination rates. The highest pycnidiospore production (67,600 pycnidiospores g-1) was obtained using barley grain as a substrate with incubation at 27ºC under a 12-h light dark-1 cycle.. A produção e a germinação de picnidiosporos de Stenocarpella maydis foram avaliadas in vitro sob a influência da composição de substratos (sorgo, trigo, aveia preta e cevada), regime de luminosidade (escuro contínuo, fotoperíodo de 12h ou luz contínua) e temperatura de inbucação (21, 24, 27, 30 ou 33ºC). Três discos de 5 mm de cultura monospórica de S. maydis foram inoculados em cada substrato. A produção e o percentual de germinação de picnidiosporos foram avaliados aos 14 dias após a inoculação. Grãos de cevada, aveia preta e trigo foram os melhores substratos na produção e germinação de picnidiosporos de S. maydis. A maior concentração (67.600 picnidiosporos g-1) foi obtida em grãos de cevada, à 27ºC e 12h de fotoperíodo.

Several isolates of coelomycetous fungi with pigmented conidia were consistently isolated from diseased roots of Zea mays in irrigated plots monitored in the KwaZulu-Natal Province of South Africa. Based on their morphology, these isolates could be identified as representative of Stenocarpella macrospora, S. maydis, and Phaeocytostroma ambiguum. Although species of Stenocarpella are well-known as causal agents of cob and stalk rot and leaf blight of maize in South Africa, the occurrence and importance of P. ambiguum is less well documented and understood. To determine the role of P. ambiguum as a root pathogen of maize, pathogenicity tests were conducted under glasshouse conditions at 18 °C night and 28 °C day temperatures using a pasteurised soil, river sand and perlite medium and a 0.5 % sand-bran inoculum. Based on these results, P. ambiguum was shown to be a primary pathogen of maize, but to be less virulent than the positive control, S. maydis. Furthermore, to clarify the higher-level phylogeny of these fungal genera, isolates were subjected to DNA sequencing of the nuclear ribosomal DNA (ITS & LSU). Partial gene sequences of the translation elongation factor 1-alpha gene were added to confirm the species monophyly. To resolve the generic placement of Phaeocytostroma, additional species such as P. sacchari, P. plurivorum and P. megalosporum were also added to the analysis. Based on these results, Stenocarpella and Phaeocytostroma were shown to be two well defined genera, belonging to Diaporthales , Diaporthaceae, being closely allied to Phomopsis (Diaporthe). All three genera were also observed to form alpha as well as beta conidia, and although this phenomenon is well documented for Phomopsis and Phaeocytostroma, it is a new observation for Stenocarpella. In spite of the differences in conidial pigmentation, no support could be obtained for polyphyly in Diaporthaceae, suggesting that as observed in Botryosphaeriaceae (Botryosphaeriales), conidial pigmentation is not informative at the family level in Diaporthales.

Botryosphaeriaceae species are pathogens of apple and many other woody hosts worldwide. In this study, 34 apple orchards belonging to 22 farmers located in the south of Uruguay, the main apple production region, were surveyed. Stem canker, die-back and fruit rot were consistently observed, the most serious damage being due to cankers. From the 91 Botryosphaeriaceae isolates obtained, eight species belonging to the genera Botryosphaeria, Diplodia, Neofusicoccum and Lasiodiplodia were identified by means of phenotypic characteristics and phylogenetic analysis of the ITS region and the TEF-1α gene. The predominant species was Botryosphaeria dothidea (56) and the second most important was Diplodia seriata (16). Other species found were Neofusicoccum parvum (8), D. intermedia (5), N. luteum (3), D. pseudoseriata (1), N. australe (1) and Lasiodiplodia theobromae (1). D. pseudoseriata and L. theobromae were associated with apple for the first time. Most of the eight species were isolated from both stem and fruit and were distributed throughout the apple-producing region. Isolates of all species were able to cause typical symptoms in stems and fruits of apple when inoculated, but the most severe symptoms were caused by L. theobromae, N. parvum and N. luteum. [ABSTRACT FROM AUTHOR]