The order Ophiostomatales includes many species important for forestry, causing plant diseases. They are common associates of bark- and wood-dwelling beetles. Two new ophiostomatalean fungi viz. Ophiostoma babimostense sp. nov. and Sporothrix europaea sp. nov. are proposed, based on morphological characters and multigene phylogenies. Ophiostoma babimostense belongs to the Ophiostoma ulmi species complex and was isolated from fallen shoots of Scots pine pruned by Tomicus species in Poland. The fungus is characterised by the production of a typical pesotum-like and sporothrix-like asexual morphs. Sporothrix europaea belongs to the Sporothrix gossypina complex and was isolated from hardwood-infested by ambrosia and bark beetles in Poland and Norway. It is characterised by the occurrence of both a sexual and asexual morphs, with long necked ascomata bearing ostiolar hyphae and a sporothrix-like asexual morph.

Forest grazing by free -roaming livestock is a common practice in many countries. The forestry sector sees the practice as unfortunate owing to several reasons, such as damages inflicted by grazing in young plantations. Concerning Norway spruce forests, a tree species known to develop wood decay with high frequency followed from stem bark damage, there is a strong perception among foresters that the trampling damage caused by livestock on the superficial root system of this tree leads to decay. Because of the very limited scientific documentation available on this topic, we pursued a clarification by investigating three 38- to 56 -year -old Norway spruce forests used for silvopasture. Two types of injuries were observed on exposed roots: bark cracks characterized by resin exudation, and injuries involving localized bark peeling and exposure of the underlying wood. These injuries occurred up to 250 cm away from the root collar, with the sector 50 -150 cm away from the root collar showing the highest incidence of injuries. In two of the forest stands, wood within the injured root areas was primarily colonized by the wound parasite Corinectria fuckeliana or species of the order Helotiales, fungi that do not cause wood decay. Wood colonization of injured roots by Heterobasidion species, the most frequent wood decay fungi of Norway spruce, was common in the third stand, but only in a few cases it was possible to deduce that the colonization had probably initiated via trampling injuries on roots. In a few cases, an injury was located at stem base at the root collar height along paths used by animals, and in such cases, it was obvious that stem colonization by Heterobasidion species had initiated via the wound. The relatively small amount of data warrants caution when drawing conclusions. Considering the high establishment frequency of decay via stem bark wounds of Norway spruce observed in previous studies, our data would suggest that roots are generally better equipped to defend themselves upon infliction of superficial wounds than stem of this tree species. The likelihood of trampling injuries leading to decay may vary considerably between different stands, this presumably depending on the level of local propagule pressure by pathogenic wood decay fungi and the frequency of damages close to root collar.

Novel species of fungi described in this study include those from various countries as follows: Australia, Baobabopsis sabindy in leaves of Eragrostis spartinoides, Cortinarius magentiguttatus among deep leaf litter, Laurobasidium azarandamiae from uredinium of Puccinia alyxiae on Alyxia buxifolia, Marasmius pseudoelegans on well-rotted twigs and litter in mixed wet sclerophyll and subtropical rainforest. Bolivia, Favolaschia luminosa on twigs of Byttneria hirsuta, Lecanora thorstenii on bark, in savannas with shrubs and trees. Brazil, Asterina costamaiae on leaves of Rourea bahiensis, Purimyces orchidacearum (incl. Purimyces gen. nov.) as root endophyte on Cattleya locatellii. Bulgaria, Monosporascus bulgaricus and Monosporascus europaeus isolated from surface-sterilised, asymptomatic roots of Microthlaspi perfoliatum. Finland, Inocybe undatolacera on a lawn, near Betula pendula. France, Inocybe querciphila in humus of mixed forest. Germany, Arrhenia oblongispora on bare soil attached to debris of herbaceous plants and grasses. Greece, Tuber aereum under Quercus coccifera and Acer sempervirens. India, Alfoldia lenyadriensis from the gut of a Platynotus sp. beetle, Fulvifomes subramanianii on living Albizzia amara, Inosperma pavithrum on soil, Phylloporia parvateya on living Lonicera sp., Tropicoporus maritimus on living Peltophorum pterocarpum. Indonesia, Elsinoe atypica on leaf of Eucalyptus pellita. Italy, Apiotrichum vineum from grape wine, Cuphopyllus praecox among grass. Madagascar, Pisolithus madagascariensis on soil under Intsia bijuga. Netherlands, Cytosporella calamagrostidis and Periconia calamagrostidicola on old leaves of Calamagrostis arenaria, Hyaloscypha caricicola on leaves of Carex sp., Neoniesslia phragmiticola (incl. Neoniesslia gen. nov.) on leaf sheaths of standing dead culms of Phragmites australis, Neptunomyces juncicola on culms of Juncus maritimus, Zenophaeosphaeria calamagrostidis (incl. Zenophaeosphaeria gen. nov.) on culms of Calamagrostis arenaria. Norway, Hausneria geniculata (incl. Hausneria gen. nov.) from a gallery of Dryocoetes alni on Alnus incana. Pakistan, Agrocybe auriolus on leaf litter of Eucalyptus camaldulensis, Rhodophana rubrodisca in nutrient-rich loamy soil with Morus alba. Poland, Cladosporium nubilum from hypersaline brine, Entomortierella ferrotolerans from soil at mines and postmining sites, Pseudopezicula epiphylla from sooty mould community on Quercus robur, Quixadomyces sanctacrucensis from resin of Pinus sylvestris, Szafranskia beskidensis (incl. Szafranskia gen. nov.) from resin of Abies alba. Portugal, Ascocoryne laurisilvae on degraded wood of Laurus nobilis, Hygrocybe madeirensis in laurel forests, Hygrocybula terracocta (incl. Hygrocybula gen. nov.) on mossy areas of laurel forests planted with Cryptomeria japonica. Republic of Kenya, Penicillium gorferi from a sterile chicken feather embedded in a soil sample. Slovakia, Cerinomyces tatrensis on bark of Pinus mugo, Metapochonia simonovicovae from soil. South Africa, Acremonium agapanthi on culms of Agapanthus praecox, Alfaria elegiae on culms of Elegia ebracteata, Beaucarneamyces stellenboschensis (incl. Beaucarneamyces gen. nov.) on dead leaves of Beaucarnea stricta, Gardeniomyces kirstenboschensis (incl. Gardeniomyces gen. nov.) rotting fruit of Gardenia thunbergia, Knufia dianellae on dead leaves of Dianella caerulea, Lomaantha quercina on twigs of Quercus suber. Melanina restionis on dead leaves of Restio duthieae, Microdochium buffelskloofinum on seeds of Eragrostis cf. racemosa, Thamnochortomyces kirstenboschensis (incl. Thamnochortomyces gen. nov.) on culms of Thamnochortus fraternus, Tubeufia hagahagana on leaves of Hypoxis angustifolia, Wingfieldomyces cypericola on dead leaves of Cyperus papyrus. Spain, Geastrum federeri in soil under Quercus suber and Q. canariensis, Geastrum nadalii in calcareous soil under Juniperus, Quercus, Cupressus, Pinus and Robinia, Hygrocybe garajonayensis in laurel forests, Inocybe cistophila on acidic soil under Cistus ladanifer, Inocybe sabuligena in a mixed Quercus ilex subsp. ballota/Juniperus thurifera open forest, Mycena calongei on mossy bark base of Juniperus oxycedrus, Rhodophana ulmaria on soil in Ulmus minor forest, Tuber arriacaense in soil under Populus pyramidalis, Volvariella latispora on grassy soils in a Quercus ilex ssp. rotundifolia stand. Sweden, Inocybe iota in alpine heath on calcareous soil. Thailand, Craterellus maerimensis and Craterellus sanbuakwaiensis on laterite and sandy soil, Helicocollum samlanense on scale insects, Leptosporella cassiae on dead twigs of Cassia fistula, Oxydothis coperniciae on dead leaf of Copernicia alba, Russula mukdahanensis on soil, Trechispora sangria on soil, Trechispora sanpatongensis on soil. Türkiye, Amanita corylophila in a plantation of Corylus avellana. Ukraine, Pararthrophiala adonis (incl. Pararthrophiala gen. nov.) on dead stems of Adonis vernalis. USA, Cladorrhinum carnegieae from Carnegiea gigantea, Dematipyriformia americana on swab from basement wall, Dothiora americana from outside air, Dwiroopa aeria from bedroom air, Lithohypha cladosporioides from hospital swab, Macroconia verruculosa on twig of Ilex montana, associated with black destroyed ascomycetous fungus and Biatora sp., Periconia floridana from outside air, Phytophthora fagacearum from necrotic leaves and shoots of Fagus grandifolia, Queenslandipenidiella californica on wood in crawlspace. Morphological and culture characteristics are supported by DNA barcodes. Citation: Crous PW, Jurjević Z, Balashov S, De la Peña-Lastra S, Mateos A, Pinruan U, Rigueiro-Rodríguez A, Osieck ER, Altés A, Czachura P, Esteve-Raventós F, Gunaseelan S, Kaliyaperumal M, Larsson E, Luangsa-ard JJ, Moreno G, Pancorbo F, Piątek M, Sommai S, Somrithipol S, Asif M, Delgado G, Flakus A, Illescas T, Kezo K, Khamsuntorn P, Kubátová A, Labuda R, Lavoise C, Lebel T, Lueangjaroenkit P, Maciá-Vicente JG, Paz A, Saba M, Shivas RG, Tan YP, Wingfield MJ, Aas T, Abramczyk B, Ainsworth AM, Akulov A, Alvarado P, Armada F, Assyov B, Avchar R, Avesani M, Bezerra JL, Bhat JD, Bilański P, Bily DS, Boccardo F, Bozok F, Campos JC, Chaimongkol S, Chellappan N, Costa MM, Dalecká M, Darmostuk V, Daskalopoulos V, Dearnaley J, Dentinger BTM, De Silva NI, Dhotre D, Carlavilla JR, Doungsa-ard C, Dovana F, Erhard A, Ferro LO, Gallegos SC, Giles CE, Gore G, Gorfer M, Guard FE, Hanson S-A, Haridev P, Jankowiak R, Jeffers SN, Kandemir H, Karich A, Kisło K, Kiss L, Krisai-Greilhuber I, Latha KPD, Lorenzini M, Lumyong S, Manimohan P, Manjón JL, Maula F, Mazur E, Mesquita NLS, Młynek K, Mongkolsamrit S, Morán P, Murugadoss R, Nagarajan M, Nalumpang S, Noisripoom W, Nosalj S, Novaes QS, Nowak M, Pawłowska J, Peiger M, Pereira OL, Pinto A, Plaza M, Polemis E, Polhorský A, Ramos DO, Raza M, Rivas-Ferreiro M, Rodriguez-Flakus P, Ruszkiewicz-Michalska M, Sánchez A, Santos A, Schüller A, Scott PA, Şen İ, Shelke D, Śliwa L, Solheim H, Sonawane H, Strašiftáková D, Stryjak-Bogacka M, Sudsanguan M, Suwannarach N, Suz LM, Syme K, Taşkın H, Tennakoon DS, Tomka P, Vaghefi N, Vasan V, Vauras J, Wiktorowicz D, Villarreal M, Vizzini A, Wrzosek M, Yang X, Yingkunchao W, Zapparoli G, Zervakis GI, Groenewald JZ (2024). Fungal Planet description sheets: 1614-1696. Fungal Systematics and Evolution 13: 183-440. doi: 10.3114/fuse.2024.13.11.

The ash dieback fungus, Hymenoscyphus fraxineus, considered to originate from East Asia, is threatening European ash (Fraxinus excelsior) on a continental scale. Trees of all ages are attacked, but young trees are particularly susceptible. It is estimated that about five percent of the ash trees in a forest have some resistance to the disease. As a result of extensive damage and high mortality throughout the natural range of European ash, the tree species is now red listed in many European countries, including Norway. Tolerance to ash dieback is also affected by environmental conditions and biotic stressors. The decline of ash and the subsequent shift in tree species has major implications for European forestry, but also for biodiversity, as many species are associated with ash. Since the first observations of ash dieback in the early 1990s, the focus by the scientific community for the following years was to identify the cause of this disease. Once the causative pathogen was identified in 2006, the research focus shifted to understanding the mode of spread and infection by H. fraxineus. Along with the increasing dieback of European ash across Europe, the current research focus is on understanding how the disease and biodiversity supported by ash could be managed through silvicultural practices coupled with the use of disease resistant ash genotypes and tree breeding. The aim of this presentation is to summarize the current understanding of the spread and mode of infection of H. fraxineus, the interactions of the pathogen with indigenous fungi associated with ash and environmental factors, and the possibilities of using silvicultural methods and tree breeding to control the disease and minimize the cascading effects of ash dieback on species closely associated with European ash.

IntroductionThe ascomycete Hymenoscyphus fraxineus, originating from Asia, is currently threatening common ash (Fraxinus excelsior) in Europe, massive ascospore production from the saprotrophic phase being a key determinant of its invasiveness.MethodsTo consider whether fungal diversity and succession in decomposing leaf litter are affected by this invader, we used ITS-1 metabarcoding to profile changes in fungal community composition during overwintering. The subjected ash leaf petioles, collected from a diseased forest and a healthy ash stand hosting the harmless ash endophyte Hymenoscyphus albidus, were incubated in the forest floor of the diseased stand between October 2017 and June 2018 and harvested at 2–3-month intervals.ResultsTotal fungal DNA level showed a 3-fold increase during overwintering as estimated by FungiQuant qPCR. Petioles from the healthy site showed pronounced changes during overwintering; ascomycetes of the class Dothideomycetes were predominant after leaf shed, but the basidiomycete genus Mycena (class Agaricomycetes) became predominant by April, whereas H. albidus showed low prevalence. Petioles from the diseased site showed little change during overwintering; H. fraxineus was predominant, while Mycena spp. showed increased read proportion by June.DiscussionThe low species richness and evenness in petioles from the diseased site in comparison to petioles from the healthy site were obviously related to tremendous infection pressure of H. fraxineus in diseased forests. Changes in leaf litter quality, owing to accumulation of host defense phenolics in the pathogen challenged leaves, and strong saprophytic competence of H. fraxineus are other factors that probably influence fungal succession. For additional comparison, we examined fungal community structure in petioles collected in the healthy stand in August 2013 and showing H. albidus ascomata. This species was similarly predominant in these petioles as H. fraxineus was in petioles from the diseased site, suggesting that both fungi have similar suppressive effects on fungal richness in petiole/rachis segments they have secured for completion of their life cycle. However, the ability of H. fraxineus to secure the entire leaf nerve system in diseased forests, in opposite to H. albidus, impacts the general diversity and successional trajectory of fungi in decomposing ash petioles.

Ophiostomatales (Ascomycota) contains many species, most of which are associated with bark beetles. Some members of this order are plant or animal pathogens, while others colonize soil, different plant tissues, or even carpophores of some Basidiomycota. However, little is known about soil-inhabiting Ophiostomatales fungi. A survey of these fungi associated with soil under beech, oak, pine, and spruce stands in Poland yielded 623 isolates, representing 10 species: Heinzbutinia grandicarpa , Leptographium procerum , L. radiaticola , Ophiostoma piliferum , O. quercus , Sporothrix brunneoviolacea , S. dentifunda , S. eucastaneae , and two newly described taxa, namely Sporothrix roztoczensis sp. nov. and S. silvicola sp. nov. In addition, isolates collected from fallen shoots of Pinus sylvestris that were pruned by Tomicus sp. are described as Sporothrix tumida sp. nov. The new taxa were morphologically characterized and phylogenetically analyzed based on multi-loci sequence data (ITS, β-tubulin, calmodulin, and translation elongation factor 1-α genes). The Ophiostomatales species were especially abundant in soil under pine and oak stands. Leptographium procerum , S. silvicola , and S. roztoczensis were the most frequently isolated species from soil under pine stands, while S. brunneoviolacea was the most abundant in soil under oak stands. The results highlight that forest soil in Poland has a wide diversity of Ophiostomatales taxa, but further studies are required to uncover the molecular diversity and phylogenetic relationships of these fungi, as well as their roles in soil fungal communities.

Graphium species form a well-supported monophyletic lineage within the Microascales (Ascomycota). Members of this genus can be found in association with bark beetles, as well as on tree wounds and in soils. During surveys of bark and ambrosia beetle-associated fungi and cavities made by woodpeckers on hardwood trees in Poland, many isolates with an affinity to Graphium were recovered. They were identified based on their morphological characters and sequence data for the internal transcribed spacer (ITS), 28S rDNA, β-tubulin (TUB2), and translation elongation factor 1-α (TEF1) gene regions. The results revealed five new species, described here as G. brachiatum, G. longistipitatum, G. polonicum, G. radicatum, and G. trypophloei.

The populations of European ash and its harmless fungal associate Hymenoscyphus albidus are in decline owing to ash dieback caused by the invasive Hymenoscyphus fraxineus , a fungus that in its native range in Asia is a harmless leaf endophyte of local ash species. To clarify the behavior of H. albidus and its spatial and temporal niche overlap with the invasive relative, we used light microscopy, fungal species-specific qPCR assays, and PacBio long-read amplicon sequencing of the ITS1-5.8S-ITS2 region to examine fungal growth and species composition in attached leaves of European ash. The plant material was collected from a healthy stand in central Norway, where ash saplings in late autumn showed leaflet vein necrosis like that commonly related to H. fraxineus . For reference, leaflet samples were analyzed from stands with epidemic level of ash dieback in southeastern Norway and Estonia. While H. albidus was predominant in the necrotic veins in the healthy stand, H. fraxineus was predominant in the diseased stands. Otherwise, endophytes with pathogenic potential in the genera Venturia (anamorph Fusicladium ), Mycosphaerella (anamorph Ramularia ), and Phoma , and basidiomycetous yeasts formed the core leaflet mycobiome both in the healthy and diseased stands. In necrotic leaf areas with high levels of either H. albidus or H. fraxineus DNA, one common feature was the high colonization of sclerenchyma and phloem, a region from which the ascomata of both species arise. Our data suggest that H. albidus can induce necrosis in ash leaves, but that owing to low infection pressure, this first takes place in tissues weakened by autumn senescence, 1–2 months later in the season than what is characteristic of H. fraxineus at an epidemic phase of ash dieback. The most striking difference between these fungi would appear to be the high fecundity of H. fraxineus . The adaptation to a host that is phylogenetically closely related to European ash, a tree species with high occurrence frequency in Europe, and the presence of environmental conditions favorable to H. fraxineus life cycle completion in most years may enable the build-up of high infection pressure and challenge of leaf defense prior to autumn senescence.

Novel species of fungi described in this study include those from various countries as follows: Argen-tina, Colletotrichum araujiae on leaves, stems and fruits of Araujia hortorum. Australia, Agaricus pateritonsus on soil, Curvularia fraserae on dying leaf of Bothriochloa insculpta, Curvularia millisiae from yellowing leaf tips of Cyperus aromaticus, Marasmius brunneolorobustus on well-rotted wood, Nigrospora cooperae from necrotic leaf of Heteropogon contortus, Penicillium tealii from the body of a dead spider, Pseudocercospora robertsiorum from leaf spots of Senna tora, Talaromyces atkinsoniae from gills of Marasmius crinis-equi and Zasmidium pearceae from leaf spots of Smilax glyciphylla. Brazil, Preussia bezerrensis from air. Chile, Paraconiothyrium kelleni from the rhizosphere of Fragaria chiloensis subsp. chiloensis f. chiloensis. Finland, Inocybe udicola on soil in mixed forest with Betula pendula, Populus tremula, Picea abies and Alnus incana. France, Myrmecridium normannianum on dead culm of unidentified Poaceae. Germany, Vexillomyces fraxinicola from symptomless stem wood of Fraxinus excelsior. India, Diaporthe limoniae on infected fruit of Limonia acidissima, Didymella naikii on leaves of Cajanus cajan, and Fulvifomes mangroviensis on basal trunk of Aegiceras corniculatum. Indonesia, Penicillium ezekielii from Zea mays kernels. Namibia, Neocamarosporium calicoremae and Neocladosporium calicoremae on stems of Calicorema capitata, and Pleiochaeta adenolobi on symptomatic leaves of Adenolobus pechuelii. Netherlands, Chalara pteridii on stems of Pteridium aquilinum, Neomackenziella juncicola (incl. Neomackenziella gen. nov.) and Sporidesmiella junci from dead culms of Juncus effusus. Pakistan, Inocybe longistipitata on soil in a Quercus for-est. Poland, Phytophthora viadrina from rhizosphere soil of Quercus robur, and Septoria krystynae on leaf spots of Viscum album. Portugal (Azores), Acrogenospora stellata on dead wood or bark. South Africa, Phyllactinia greyiae on leaves of Greyia sutherlandii and Punctelia anae on bark of Vachellia karroo. Spain, Anteaglonium lusitanicum on decaying wood of Prunus lusitanica subsp. lusitanica, Hawksworthiomyces riparius from fluvial sediments, Lophiostoma carabassense endophytic in roots of Limbarda crithmoides, and Tuber mohedanoi from calcareus soils. Spain (Canary Islands), Mycena laurisilvae on stumps and woody debris. Sweden, Elaphomyces geminus from soil under Quercus robur. Thailand, Lactifluus chiangraiensis on soil under Pinus merkusii, Lactifluus nakhonphanomensis and Xerocomus sisongkhramensis on soil under Dipterocarpus trees. Ukraine, Valsonectria robiniae on dead twigs of Robinia hispida. USA, Spiralomyces americanus (incl. Spiralomyces gen. nov.) from office air. Morphological and culture characteristics are supported by DNA barcodes.

The genus Ceratocystiopsis (Ophiostomatales, Ascomycota) includes 21 species, which can be found mainly in association with bark beetles in the Northern Hemisphere. A survey of Ceratocystiopsis species associated with bark beetles infesting Picea abies and Pinus sylvestris in Norway yielded 126 isolates, representing Ceratocystiopsis neglecta and Ceratocystiopsis rollhanseniana, and four species described herein as Ceratocystiopsis chalcographii, Ceratocystiopsis debeeria, Ceratocystiopsis norroenii and Ceratocystiopsis troendelagii. The new taxa were morphologically characterised and phylogenetically analysed on the basis of sequence data of multiple loci (ITS, LSU, beta-tubulin (TUB2), calmodulin (CAL) and translation elongation factor 1-alpha (TEF1) genes). Ceratocystiopsis norroenii and C. rollhanseniana were the most frequently isolated species, and the latter species had the wider vector range.

Lettuce (Lactuca sativa L.) is produced in Norway both in field and greenhouses. In Norway, greenhouse lettuce is one of the most important vegetables grown year-round. In winter 2018, wilting symptoms were observed on soil-grown lettuce of the cultivar Frillice in a greenhouse in south east Norway (Buskerud county). Affected plants showed stunted growth, wilting of outer leaves, and brownish discoloration of vascular tissues of taproots and crowns. According to the producer, the disease led to an estimated 10% of yield losses. Fungal isolates were obtained from crowns and roots of diseased plants collected from the greenhouse in 2018 and 2019. Two single spore isolates, 231274 from 2018 and 231725 from 2019, were used in further studies. The isolates were incubated on synthetic nutrient-poor agar (SNA) at 18-20 ⁰C, and a 12 hours dark, 12 hours UV light cycle. Isolate 231274 produced abundant macro- and microconidia characteristics of Fusarium oxysporum while macroconidia were never observed in isolate 231725. On potato dextrose agar (PDA), colonies of isolate 231274 were purple in color and colonies of isolate 231725 were pinkish with abundant aerial mycelium. For PCR-assay, DNA from mycelia was extracted using Easy-DNA kit (Invitrogen). A portion of the translation elongation factor 1-α (EF1-α) gene was amplified using primers F-728F (Carbone and Kohn. 1999) and EF2 (O'Donnell et al. 1998) as described by Aas et al. 2018. Blast analysis of both sequences (accession no. MW316853 for 231274 and MW316854 for 231275) obtained a 99% homology with the sequence of Fusarium oxysporum f.sp. lactucae (FOL) race 1 strain S1 (accession no. DQ837657)(Mbofung et al. 2007). Both isolates were identified as race 1 by using specific primers Hani3' and Hanilatt3rev (Pasquali et al. 2007) as described by Cabral et al. 2014. To complete Koch's postulate, lettuce plants of the cultivar Frillice were used. Race identity was confirmed using the differential lettuce cultivars Costa Rica No.4 (resistant to FOL race 1), Banchu Red Fire (resistant to FOL races 2 and 4) and Romana Romabella (resistant to FOL races 1 and 2) (Gilardi et al. 2017) provided by the breeding company Rijk Zwaan (De Lier, The Netherlands). For inoculation, roots of six 2-weeks old seedlings per cultivar were dipped in a spore suspension (1 x 106 CFU/ml) for 1 min, while controls were dipped in distilled water. Seedlings were planted in 250 ml pots containing fertilized potting substrate, and were placed in a greenhouse with temperature ranging from 15 to 35 ⁰C and an average of 23 ⁰C. After 10 days reduced growth was observed in cultivars Frillice and Banchu Red Fire for both fungal isolates. After 25 days wilting was observed in both cultivars. Affected plants presented discoloration of vascular tissue. No difference in growth was observed between cultivars Romana Romabella and Costa Rica No. 4 and their respective controls. FOL was re-isolated from all inoculated cultivars but not from controls. The colony patterns of the recovered isolates were the same than those of the isolates used for inoculation. These results confirm that the isolate belongs to race 1. Greenhouse lettuce in Norway is mainly produced in hydroponics. FOL is here reported to cause damages in soil- grown lettuce. Nevertheless FOL in hydroponic systems has been reported in Japan (Fujinaga et al. 2003) and Thailand (Thongkamngam and Jaenaksorn 2017). Thus, the possibility of infections in hydroponics remain a big concern for lettuce production in Norway.

Sporothrix (Sordariales, Ascomycota) is a well-supported monophyletic lineage within the Ophiostomatales, species of which occur in a diverse range of habitats including on forest trees, in the soil, associated with bark beetles and mites as well as on the fruiting bodies of some Basidiomycota. Several species have also been reported as important human and animal pathogens. During surveys of insect- and wound-associated Ophiostomatales from hardwood trees in Poland, many isolates with affinity to Sporothrix were recovered. In the present study, six undescribed Sporothrix spp. collected during these surveys are characterized based on their morphological characteristics and multi-locus phylogenenetic inference. They are described as Sporothrixcavum, Sporothrixcracoviensis, S.cryptarchum, S.fraxini, S.resoviensis, and S.undulata. Two of the Sporothrix spp. reside in the S.gossypina-complex, while one forms part of the S.stenoceras-complex. One Sporothrix sp. is a member of lineage F, and two other species grouped outside any of the currently defined species complexes. All the newly described species were recovered from hardwood habitats in association with sub-cortical insects, wounds or woodpecker cavities. These species were morphologically similar, with predominantly asexual states having hyaline or lightly pigmented conidia, which produce holoblastically on denticulate conidiogenous cells. Five of the new taxa produce ascomata with necks terminating in long ostiolar hyphae and allantoid ascospores without sheaths. The results suggest that Sporothrix species are common members of the Ophiostomatales in hardwood ecosystems of Poland.

The relationship between the ecological success of needle pathogens of forest trees and species richness of co-inhabiting endophytic fungi is poorly understood. One of the most dangerous foliar pathogens of pine is Dothistroma septosporum, which is a widely spread threat to northern European forests. We sampled two Pinus sylvestris sites in Estonia and two in Norway in order to analyse the relations between the abundance of D. septosporum and overall fungal richness, specific fungal species composition, time of season, needle age and position in the canopy. In both countries, the overall species richness of fungi was highest in autumn, showing a trend of increase with needle age. The overall species richness in the second-year needles in Estonia and third-year needles in Norway was similar, suggesting that a critical colonization threshold for needle shed in P. sylvestris is breached earlier in Estonia than in Norway. The fungal species richness in P. sylvestris needles was largely affected by Lophodermium conigenum. Especially in older needles, the relative abundance of L. conigenum was significantly higher in spring compared to summer or autumn. The timing of recruitment and colonization mechanisms of different foliage endophytes are shortly discussed.

The genus Ceartocystiopsis includes ascomycetes fungi belonging to the Ophiostomatales that are not well recognized in the world. Described species so far have been found mainly in association with bark beetles in the Northern Hemisphere. The aims of this study were therefore to survey of distribution of species of Ceratocystiopsis associated with bark beetles infesting Picea abies and Pinus sylvestris in Norway. Adults for 22 different bark beetle species were collected from 13 stands in Norway. During this study, we recovered 126 isolates showing affinities to Ceratocystiopsis representing six species, including two described and four undescribed taxa. The four undescribed taxa collected during this work were characterised based on their morphological characteristics and multi-gene phylogenies. Herein, we describe these new species as Ceratocystiopsis chalcographii sp. nov., Ceratocystiopsis debeeria sp. nov., Ceratocystiopsis norroenii sp. nov. and Ceratocystiopsis troendelagii sp. nov. Ceratocystiopsis norroenii and C. rollhanseniana were the most frequently isolated species although the latter species had a much wider vector range. This study expands our knowledge about the taxonomy and species diversity of Ceratocystiopsis and beetle-fungus relationships.

Dothistroma septosporum, the primary causal agent of Dothistroma needle blight, is one of the most significant foliar pathogens of pine worldwide. Its wide host and environmental ranges have led to its global success as a pathogen and severe economic damage to pine forests in many regions. This comprehensive global population study elucidated the historical migration pathways of the pathogen to reveal the Eurasian origin of the fungus. When over 3800 isolates were examined, three major population clusters were revealed: North America, Western Europe, and Eastern Europe, with distinct subclusters in the highly diverse Eastern European cluster. Modeling of historical scenarios using approximate Bayesian computation revealed the North American cluster was derived from an ancestral population in Eurasia. The Northeastern European subcluster was shown to be ancestral to all other European clusters and subclusters. The Turkish subcluster diverged first, followed by the Central European subcluster, then the Western European cluster, which has subsequently spread to much of the Southern Hemisphere. All clusters and subclusters contained both mating-types of the fungus, indicating the potential for sexual reproduction, although asexual reproduction remained the primary mode of reproduction. The study strongly suggests the native range of D. septosporum to be in Eastern Europe (i.e., the Baltic and Western Russia) and Western Asia.

Diplodia sapinea is a cosmopolitan endophyte and opportunistic pathogen having occurred on several conifer species in Europe for at least 200 years. In Europe, disease outbreaks have increased on several Pinus spp. in the last few decades. In this study, the genetic structure of the European and western Asian D. sapinea population were investigated using 13 microsatellite markers. In total, 425 isolates from 15 countries were analysed. A high clonal fraction and low genetic distance between most subpopulations was found. One single haplotype dominates the European population, being represented by 45.3% of all isolates and found in nearly all investigated countries. Three genetically distinct subpopulations were found: Central/North European, Italian and Georgian. The recently detected subpopulations of D. sapinea in northern Europe (Estonia) share several haplotypes with the German subpopulation. The northern European subpopulations (Latvia, Estonia and Finland) show relatively high genetic diversity compared to those in central Europe suggesting either that the fungus has existed in the North in an asymptomatic/endophytic mode for a long time or that it has spread recently by multiple introductions. Considerable genetic diversity was found even among isolates of a single tree as 16 isolates from a single tree resulted in lower clonal fraction index than most subpopulations in Europe, which might reflect cryptic sexual proliferation. According to currently published allelic patterns, D. sapinea most likely originates from North America or from some unsampled population in Asia or central America. In order to enable the detection of endophytic or latent infections of planting stock by D. sapinea, new species-specific PCR primers (DiSapi-F and Diplo-R) were designed. During the search for Diplodia isolates across the world for species specific primer development, we identified D. africana in California, USA, and in the Canary Islands, which are the first records of this species in North America and in Spain.