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Fusarium is one of the most important phytopathogenic fungi of agricultural and human concern. More than 300 species have been described, many of which are pathogenic to important crops, flowers, forest trees, animals, and humans. Species belonging to this genus have been detected in all environments: grassland, desert, littoral, agricultural, alpine zones, aquatic, man-made, and hospitals. Despite the importance of molecular techniques for the identification of a fungal species, morphological criteria still have an important role, including for Fusarium species, for which morphological identification of species requires adequate training and experience. In this paper, we present FusaHelp, a computer-based, user-friendly tool for the morphological identification of common Fusarium species, based on the wide experience of the authors who have devoted most of their scientific careers to the identification and characterization of these species. The web-location of FusaHelp (https://www.fusahelp.com) will greatly facilitate morphological identification and is intended to provide support for all those people who work with this important genus and need a quick clue on the identification, even incomplete, of the Fusarium species that they are working with.

International audience; Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. Previously (Geiser et al. 2013; Phytopathology 103:400-408. 2013), the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani Species Complex (FSSC). Subsequently, this concept was challenged by one research group (Lombard et al. 2015 Studies in Mycology 80: 189-245) who proposed dividing Fusarium into seven genera, including the FSSC as the genus Neocosmospora, with subsequent justification based on claims that the Geiser et al. (2013) concept of Fusarium is polyphyletic (Sandoval-Denis et al. 2018; Persoonia 41:109-129). Here we test this claim, and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species recently described as Neocosmospora were recombined in Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural and practical taxonomic option available.

Citrus tristeza virus was detected for the first time in the Lao People’s Democratic Republic. Samples were collected from citrus trees across the southern provinces for testing in Australia. RNA was extracted and tested using conventional and real-time reverse transcription polymerase chain reactions with the virus detected in 12 of 59 samples tested. Viral identities were confirmed by sequencing. Additional confirmation was obtained by an enzyme-linked immunosorbent assay. The implications of the presence of this virus for citrus production in Lao are discussed briefly.

A survey of small-holder banana farms was undertaken in February/March 2019 in Savannakhet, Salavan, Sekong and Champasak provinces in southern Lao People’s Democratic Republic (Lao PDR) to establish which banana leaf pathogens were present. Twenty-five farms were visited, seven different cultivars were assessed, and 13 leaf samples with characteristic symptoms of banana freckle disease collected. Phyllosticta musarum was detected on the variety ‘Kuay Nam’ in each of the four provinces surveyed. Phyllosticta cavendishii was detected in Salavan, Sekong and Champasak. Phyllosticta musaechinesis was recorded from Champasak. This is the first time these three species have been recorded associated with banana freckle disease in the Lao PDR.

Citrus exocortis viroid, citrus bent leaf viroid, hop stunt viroid and citrus dwarfing viroid were detected for the first time in Lao PDR. Samples were collected from citrus trees across southern Lao PDR for laboratory testing in Australia. RNA was extracted and amplified using quantitative reverse transcription polymerase chain reaction (qRT-PCR); viroid identities were confirmed by sequencing.

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the

Coniella hibisci is reported for the first time in Lao P.D.R. The pathogen was isolated from roselle (Hibiscus sabdariffa var. sabdariffa) stem and leaf samples from a farm in Thateng district, Sekong province, and deposited with the International Collection of Microorganisms from Plants (ICMP). The identification of the pathogen was based on morphological features and the results of sequencing the ITS, LSU, and tef1 genetic loci. Pathogenicity tests on four-week-old roselle plants reproduced field symptoms, satisfying Koch’s postulates.

To clarify the changes in field populations of Fusarium head blight (FHB) pathogens over a decade, Fusarium species and trichothecene genotypes associated with FHB on wheat were monitored in Hebei province during the periods 2005&ndash, 2006 and 2013&ndash, 2016. Fusarium species determination was carried out by morphological identification, species-specific amplification and partial translation elongation factor (TEF-1&alpha, ) gene sequencing. Trichothecene genotype prediction was carried out by primers 3CON/3NA/3D15A/3D3 or Tri13F/Tri13R, Tri303F/Tri303R and Tri315F/Tri315R. A total of 778 purified Fusarium isolates were recovered from 42 sampling sites in 17 counties during the period 2005&ndash, 2006 and 1002 Fusarium isolates were recovered from 122 sampling sites in 65 counties during the period 2013&ndash, 2016. F. graminearum was the predominant pathogen recovered during the periods 2005&ndash, 2016. However, the pathogen composition differed slightly between the two periods. In 2005&ndash, 2006, 752 out of 778 (96.7%) of the isolates belonged to F. graminearum. Two were identified as F. culmorum. Five other Fusarium species were also recovered, F. equiseti, F. verticillioides, F. proliferatum, F. subglutinans and F. chlamydosporum, with lower recoveries of 0.4%, 0.8%, 0.8%, 0.1% and 1.0%, respectively. Trichothecene genotype prediction showed that all the 752 F. graminearum isolates were of the 15-ADON genotype. Five Fusarium species were recovered from samples collected over the period 2013&ndash, 2016. F. graminearum was again the predominant pathogen with an isolation frequency of 97.6%. F. pseudograminearum, F. asiaticum, F. culmorum and F. negundis were also isolated at a recovery of 1.4%, 0.7%, 0.2% and 0.1%, respectively. For the 2013&ndash, 2016 isolates, 971 of the 978 F. graminearum strains were 15-ADON whereas seven isolates were of the 3-ADON type. All seven F. asiaticum isolates were of the NIV type and fourteen F. pseudograminearum isolates were classified as 3-ADON. F. pseudograminearum was first isolated from FHB in Hebei in 2013. Although the recovery of F. pseudograminearum is still low, it represents a small shift in the pathogen composition and trichothecene genotypes associated with FHB in Hebei province. As Fusarium crown rot of wheat caused by F. pseudograminearum is an increasing problem in Hebei province, it is appropriate to monitor the role of F. pseudograminearum in FHB in the future.

Cereal cultivation is a major component of Tunisian agriculture. Take-all of cereals caused by the soil-borne ascomycete Gaeumannomyces tritici (syn.Gaeumannomyces graminis var. tritici) and G. avenae (syn. G. graminis. var. avenae) is a common disease worldwide. The objectives of this study were to evaluate the incidence and distribution of the disease across the cereal growing areas in different climatic regions of Tunisia, to assess the relative importance of the two species, and to investigate the impact of crop sequences on inoculum density in soil and disease incidence. During the cropping seasons of 2009/10, 2010/11, 2012/13, and 2013/14, the percentage of fields infested varied from 8.1% in 2011 to 39.6% in 2013 and the incidence of take-all varied from 0 to 60% in the 298 fields surveyed. Disease incidence was significantly higher in wetter climatic regions than in semi-arid regions. The disease was not detected in the driest area. The highest incidence of take-all was recorded in durum wheat fields. However, overall, no significant differences were observed in the incidence between durum wheat, bread wheat, and barley crops. Take-all was not detected in any oat crop. All findings in this study including surveys, molecular identification of isolated fungi, and determination of DNA concentration in soil, indicate that G. tritici is the dominant species and that G. avenae is rarely found in Tunisian cereal cropping soils. Rotation trials conducted over four cropping seasons on the experimental station showed that a one year break crop could significantly reduce the incidence and severity of take-all in durum wheat. In addition, the inoculum density of Gt/Ga in soil estimated by quantitative PCR was significantly reduced after a legume crop compared to monoculture of durum wheat, and consequently there was a significant decrease in the incidence and severity of the disease in the following year. This study highlights the influence of climatic conditions on the distribution of take-all in the cereal growing areas of Tunisia and the importance of rotation in reducing incidence and severity of take-all.

Six new species of Fusarium associated with soil and plant hosts from ecosystems of minimal anthropogenic disturbance in Australia are described. Fusarium coicis from Coix gasteenii, F. goolgardi from Xanthorrhoea glauca, F. mundagurra from soil and Mangifera indica, F. newnesense from soil, F. tjaetaba from Sorghum interjectum and F. tjaynera from soil, Triodia microstachya, Sorghum interjectum and Sorghum intrans. Morphology and phylogenetic analysis of EF-1α, RPB1 and RPB2 sequence data were used to delineate species boundaries. The new species were phylogenetically dis- tributed in the Fusarium sambucinum, F. fujikuroi ,a nd F. chlamydosporum species complexes, and two novel species complexes. These six new species have particular phylogeo- graphic significance as not only do they provide further insight into the geographic patterns of Fusarium evolution but also challenge current phylogeographic hypotheses.

Vanilla stem rot, caused by Fusarium oxysporum f. sp. vanillae (Fov), is the main constraint to increasing vanilla production in the major vanilla-producing countries, including Indonesia. The current study investigated the origin of Fov in Indonesia using a multigene phylogenetic approach. Nineteen Fov isolates were selected to represent Indonesia, the Comoros, Mexico and Reunion Island. The translation elongation factor 1 alpha gene and the mitochondrial small subunit ribosomal RNA gene phylogenies resolved the Fov isolates into three distinct clades in both phylogenetic species of the F. oxysporum species complex, indicating a polyphyletic pattern of evolution. In addition, Fov isolates from Indonesia were also polyphyletic. These results suggest that the vanilla stem rot pathogen in Indonesia has a complex origin. The implications for disease management are discussed.

The isolation of Fusarium fujikuroi from rice plants with elongated stems typical of bakanae disease in the Lao PDR is reported for the first time. The identification was based on both molecular and morphological markers. Koch’s postulates were fulfilled. Bakanae disease has long been recognized in the Lao PDR based on symptomatology, but the etiology of the disease has not been clearly defined. This study was part of a continuing program to assist with the development of checklists of pathogens and plant diseases for Lao PDR for biosecurity purposes and integrated disease management.

Fusarium is one of the most remarkable genera of the fungi. It is remarkable for it’s genetic and morphological diversity, it’s wide geographic distribution, the diversity of it’s relationships with plants, the diversity of plant diseases for which it is responsible, and its abundance and diversity in natural ecosystems. Evidence to support this contention is presented and discussed focusing on the author’s career-long and continuing research on the genus. The diversity and socio-economic importance of Fusarium diseases is illustrated by reference to diseases common in the Australasian region. Examples include the Fusarium wilts caused by formae speciales of F. oxysporum and the stalk and cob rots of maize and cereal head blights caused by F. graminearum. The importance of Fusarium mycotoxins is noted. Endophytic colonization of living plant tissue by Fusarium species remains a poorly understood and insidious phenomenon. Examples are provided in relation to crop plants and plants in natural ecosystems. The role of natural ecosystems as reservoirs of crop pathogens and potential emerging pathogens is discussed briefly in relation to disease management and biosecurity.

Bakanae disease, caused by the fungal phytopathogen Fusarium fujikuroi, can be detected in most rice (Oryza sativa L.) growing areas worldwide. In this study, we investigated the population structure of this fungus in southern Lao PDR, a country located near the geographic origin of rice domestication. Microsatellites (SSRs) and mating type (MAT) analyses, pathogenicity and fungicide sensitivity tests were integrated in the study. The first key finding is that the population genetic structure of F. fujikuroi in Lao PDR is consistent with high clonal reproduction. Indeed, (i) "true" clones were identified; (ii) within populations, MAT types were frequently skewed from 1:1 ratio, (iii) linkage disequilibrium (among SSRs as also among SSRs and MAT) was present, and (iv) gene-flow between opposite MAT types within the same population is restricted. The presence of genetic divergence among areas and populations and the occurrence of positive spatial autocorrelation of genetic variation, indicate that migration is restricted, and that genetic drift plays an important role in the evolution of this fungus. Two main well-defined groups of isolates were detected (FST = 0.213) that display a non-random spatial distribution. They differ in the ability to induce seedlings death but not seedlings elongation (the typical Bakanae symptom) suggesting that the pathogen's ability to induce the two symptoms is under different genetic control. Finally, we compared two agroecosystems with contrasting characteristics: low-input and traditional (Lao PDR) vs high-input and modern (Italy). We found differences in the level of population structuring and of spatial autocorrelation. This suggests that the evolutionary potential of the fungus not only depends on its intrinsic characteristics, but is strongly influenced by other external factors, most likely by the dynamics of infested seed exchange. Thus, quarantine and chemical treatments are a way to reduce population connectivity and hence the evolutionary potential of this pathogen.

Research was undertaken to identify Fusarium spp. associated with an endemic wild rice (Oryza australiensis) community in northern Australia and determine the incidence of species reported as pathogens of tropical grain crops. A total of 92 isolates representing six Fusarium species were recovered from O. australiensis. Taxa were delimited based on morphological and phylogenetic (TEF-1α sequence) characters and identified as F. incarnatum-equiseti species complex (55 %), Gibberella fujikuroi species complex (GFSC, 27 %), F. longipes (14 %) and an unidentified Fusarium sp. (3 %). F. sacchari was dominant in the GFSC, a reported mycotoxin (beauvericin, fumonisin) producer and pathogen of sugarcane and sorghum. No isolates were identified as F. fujikuroi, the cause of Bakanae disease of rice in south-east Asia and other rice growing regions. Morphological, phylogenetic and phenetic (AFLP) analyses were in accordance, differentiating all F. sacchari isolates from other Fusarium taxa. The ratio of F. sacchari mating types (15 MAT-1:9 MAT-2) in the O. australiensis population was not significantly different from that expected under random mating (1:1). The effective population number (Ne) based on mating type (Ne(mt)) was 94 % of the count (total population). In contrast, that based on female-fertile isolates (Ne(f)) was 15 %, implying low frequencies of sexual reproduction among F. sacchari isolates. Pathogenicities of three F. sacchari genotypes were assessed against O. australiensis and commercial cultivars of rice, sorghum and maize. All F. sacchari isolates significantly (P

In this letter, we advocate recognizing the genus Fusarium as the sole name for a group that includes virtually all Fusarium species of importance in plant pathology, mycotoxicology, medicine, and basic research. This phylogenetically guided circumscription will free scientists from any obligation to use other genus names, including teleomorphs, for species nested within this clade, and preserve the application of the name Fusarium in the way it has been used for almost a century. Due to recent changes in the International Code of Nomenclature for algae, fungi, and plants, this is an urgent matter that requires community attention. The alternative is to break the longstanding concept of Fusarium into nine or more genera, and remove important taxa such as those in the F. solani species complex from the genus, a move we believe is unnecessary. Here we present taxonomic and nomenclatural proposals that will preserve established research connections and facilitate communication within and between research communities, and at the same time support strong scientific principles and good taxonomic practice Fil: Geiser, David M.. State University of Pennsylvania; Estados Unidos Fil: Aoki, Takayuki. National Institute of Agrobiological Sciences; Japón Fil: Bacon, Charles W.. Toxicology and Mycotoxin Research; Grecia Fil: Baker, Scott E.. Pacific Northwest National Laboratory; Estados Unidos Fil: Bhattacharyya, Madan K.. University of Iowa; Estados Unidos Fil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Scandiani, María Mercedes. Laboratorio Agrícola Río Paraná. San Pedro; Argentina Fil: Ploetz, Randy C.. University of Florida; Estados Unidos Fil: Proctor, Robert H.. NCAUR-ARS-USDA; Estados Unidos Fil: Rehner, Stephen A.. United States Department of Agriculture; Estados Unidos Fil: Robert, Vincent A. R. G.. Fungal Biodiversity Center; Países Bajos Fil: Rooney, Alejandro P.. NCAUR-ARS-USDA; Estados Unidos Fil: Salleh, Baharuddin bin. University of Malaysia; Malasia Fil: Scauflaire, Jonathan. Université Catholique de Louvain; Bélgica Fil: Short, Dylan P. G.. University of California; Estados Unidos Fil: Steenkamp, Emma. University of Pretoria; Sudáfrica Fil: Suga, Haruhisa. Gifu University; Japón Fil: Summerell, Brett A.. The Royal Botanic Garden Sydney; Australia Fil: Sutton, Deanna A.. University of Texas; Estados Unidos Fil: Thrane, Ulf. Technical University of Denmark; Dinamarca Fil: Trail, Francis. Michigan State University; Estados Unidos Fil: Van Diepeningen, Anne. Fungal Biodiversity Center; Países Bajos Fil: VanEtten, Hans D.. University of Arizona; Estados Unidos Fil: Viljoen, Altus. University of Stellenbosch; Sudáfrica Fil: Waalwijk, Cees. Wageningen University; Países Bajos Fil: Ward, Todd J.. NCAUR-ARS-USDA. Pretoria; Sudáfrica Fil: Wingfield, Michael J.. University of Pretoria; Sudáfrica Fil: Xu, Jin-Rong. Purdue University; Estados Unidos Fil: Yang, Xiao-Bing. University of Iowa; Estados Unidos Fil: Yli-Mattila, Tapani. University of Turku; Finlandia Fil: Zhang, Ning. Rutgers University; Estados Unidos

Ralstonia pseudosolanacearum is reported for the first time from the Lao PDR. Typical symptoms of wilt and vascular exudate were observed in potatoes and tomatoes in Paksong district, Champasak province. Pathogenicity was proven and identification was based on symptoms, commercial diagnostic test kits and sequence of the egl gene.

Phytophthora capsici is reported for the first time in the Lao PDR. It was isolated from soil collected from the root zone of wilting red chilli (Capsicum annuum) plants in a polyhouse farm in Paksong district of Champasak province. The wilting chilli plants had typical symptoms of infection by P. capsici including root rot and necrosis of the outer cortex of the stem base. The isolate was identified using morphological and molecular markers. A pathogenicity trial demonstrated that the culture was pathogenic to a local cultivar of chilli seedlings.

This study led to the discovery of four putative entomopathogenic fungi of armoured scale insects on citrus trees in coastal New South Wales. Two of these species belong in Podonectria as P. coccicola (Ellis & Everh.) Petch (syn. Tetracrium coccicola (Hohn.) Ellis & Everh.) and P. novae-zelandiae Dingley. Members of this genus are grown in culture for the first time. Formerly placed in the Pleosporales, Tubeufiaceae, or more recently in the Tubeufiales, these species are herein placed in the new family Podonectriaceae fam. nov., Pleosporales. Another species is placed in the Hypocreales, Bionectriaceae as Clonostachys coccicola (J.A. Stev.) H.T. Dao comb. nov. (basionym Tubercularia coccicola J.A. Stev., syn. Nectria tuberculariae Petch). The fourth species is Myriangium citri Henn. (Myriangiales, Myriangiaceae). Each fungal species is characterized and the phylogenetic placement confirmed by molecular analyses of the ITS and 28 s rDNA regions. In addition, their biology is noted, including location of the fungi within tree canopies.

Fusarium oxysporum f.sp. niveum is reported for the first time in the Lao PDR. It was isolated from watermelons (Citrullus lanatus) in Songkhon district, Savannahkhet province following a limited ad hoc survey during January and February of 2015. Infected plants showed symptoms of wilt, vascular discolouration, necrosis in the collar region, lower stem base and upper taproot regions, and whole plant death. Identification of the pathogen was confirmed through phylogenetic analysis of the EF1-α locus and a pathogenicity test satisfying Koch’s postulates.

A major problem with contamination of fungal and bacterial cultures by Neurospora in the diagnostic laboratory of the Plant Pathology Unit at the Plant Protection Centre in Vientiane, Laos, occurred in May 2009 and again in April-May 2010. The problem persisted despite sterilization of all contaminated cultures and stringent disinfection procedures. Initial attempts to identify the source were unsuccessful. However in May 2010 the senior author realised that the orange fungus common on old sticky rice in traditional baskets was Neurospora. A limited survey indicated that this was a key source of conidia in the precinct around the laboratory, and elsewhere in Vientiane. A sample was collected and forwarded to the second author at the Plant and Microbial Biology Department in the University of California, Berkeley, California, USA, for confirmation of the genus, and identification of the species. It was identified as N. intermedia (Tai Mycologia 27:289–294 1935), and the isolate used in the phylogenetic study was deposited in the Fungal Genetics Stock Centre as FGSC10868. This is the first report of a Neurospora species in Lao.

Phytophthora capsici is an economically significant pathogen of various important annual and perennial crops in temperate and tropical regions. Not much is known about the genetic diversity of this pathogen worldwide. In Vietnam it is the causal agent of devastating diseases on several hosts, including chilli and black pepper. Crossinfectivity of P. capsici isolates obtained from the two hosts was demonstrated. Analysis of forty-six P. capsici isolates based on Random Amplified Microsatellites (RAMS) and Repetitive Extragenic Palindromic (REP) fingerprinting revealed that isolates from black pepper were genetically distinct from isolates recovered from chilli. Twenty-two isolates from chilli clustered into two clonal groups at a DICE similarity level of >85%, whereas twenty-four isolates from black pepper were separated from these chilli isolates at a similarity level of

Phytophthora foot rot of black pepper caused by Phytophthora capsici is a major disease of black pepper throughout production areas in Vietnam. The disease causes collar, foot and tap root rots and eventual death of the infected vine. Potassium phosphonate was evaluated for the control of this disease in greenhouse and field trials. In greenhouse trials three-month-old vines treated with phosphonate by soil drenching (10–20 g a.i./l) and then inoculated with P. capsici mycelium (2% v/v soil) had significantly less foot rot compared to vines grown in non-treated soil. In field trials mature vines were treated with phosphonate at 50–100 g a.i/pole soil drenching or 10 g a.i./l by root infusion. After 10 days root, stem and leaf specimens were removed for bioassay by inoculation with 5 ml of P. capsici zoospores suspension (106–108 spores/ml). Soil drenching with phosphonate inhibited the colonisation of pathogen on excised leaf, stem and root tissues, significantly more than phosphonate root infusion. Our s...

Arbuscular mycorrhizal (AM) fungi convey well documented benefits to plant growth in domesticated species. We investigated AM in Solanum centrale, a desert shrub of central Australia and traditional food for Indigenous Australians. AM were observed in roots of S. centrale from wild and cultivated stands of different ages and management regimes. Greenhouse seedlings grown in sterilised sand were provided with no or minor additions of phosphorus, with or without AM fungi. Inoculated seedlings not fertilised with phosphorus exhibited moderate AM formation. Added phosphorus resulted in an absence of AM. Inoculation did not significantly affect dry weight, root length and plant height of seedlings fertilised with phosphorus but significantly increased the size of unfertilised seedlings. Inoculation significantly increased root phosphorus content, decreased root to shoot ratio and decreased root biomass at all phosphorus additions, despite the absence of observable AM. Thus it appears AM fungi in the root zone influenced certain plant characteristics, regardless of phosphorus nutrition. Overall, S. centrale benefited from the presence of AM through increased phosphorus uptake, but only when the seedlings were growing in soil with extremely low available phosphorus. The response was immediate in our experimental system and is likely to be important in the wild.

A new species of Fusarium associated with Australian soils in non-cultivated ecosystems is described as Fusarium burgessii on the basis of morphological and phylogenetic data. Isolates recovered from biogeographical surveys over 26 years were selected for morphological examination. Two distinct morphotypes with morphological affinities to the Fusarium oxysporum, Fusarium redolens and Gibberella fujikuroi species complexes were observed. Phylogenetic resolution based on the translation elongation factor1α (EF-1α) and the second largest subunit of the RNA polymerase II gene (RPB2) separated the two morphotypes into novel phylogenetic Fusarium species, with one morphotype being assigned the species epithet Fusarium burgessii sp. nov. Phylogenetic analysis of the RPB2 locus with representatives of all the major Fusarium species complexes provides evidence that F. burgessii is part of a unique monophyletic lineage of species in the genus Fusarium.

Fusarium species associated with plants as pathogens, saprobes and endophytes in Australia are listed with notes on their pathogenicity and toxicity provided. A list of Fusarium species not known to occur in Australia also is provided and their quarantine significance evaluated.

Two new species of Fusarium associated with Australian indigenous grasses in natural ecosystems are described as F. lyarnte and F. werrikimbe on the basis of morphology, DNA fingerprinting and phylogenetic analysis of EF-1α and β-tubulin sequence data. Isolates of these species were initially recovered from soil in the McGraths Creek area of central Australia and subsequently recovered from soil and stems of the indigenous grass Sorghum interjectum from Litchfield National Park in the Northern Territory, and from Sorghum leiocladum from Werrikimbe National Park in New South Wales. The common feature of both of these species is the production of large globose microconidia in false heads on polyphialides. Attempts to apply the biological species concept were unsuccessful.

Cultures morphologically similar to F. brevicatenulatum and F. pseudoanthophilum were recovered from millet collected in Kenya. Morphological characterisation showed that the production of pyriform microconidia and chlamydospores, key characters separating these species from each other and from other Fusarium species, was variable in these cultures. Sexual compatibility studies of these isolates and holotype cultures of F. brevicatenulatum and F. pseudoanthophilum revealed that they belonged to the same biological species. No fertile crosses were observed between putative isolates of F. brevicatenulatum from millet and tester strains of F. verticillioides, F. sacchari, F. proliferatum, F. subglutinans, F. thapsinum, and F. konzum. Neither were fertile crosses obtained from any self-cross tests, indicating that the cultures were heterothallic. Further studies using AFLP, and sequencing of the β-tubulin, calmodulin, and translation elongation factor 1-α genes revealed that the isolates from the millets and those of the ex-holotype cultures of F. brevicatenulatum and F. pseudoanthophilum belonged to the same species. The species epithet F. brevicatenulatum is preferred on the basis of priority.

Previous studies have evaluated the overall structure of populations of Fusarium pseudograminearum (teleomorph, Gibberella coronicola ), causal agent of cereal crown rot, but there is no information available on spatial relationships of genetic variation in field populations. Three 1-m-row sections in crown-rot-affected wheat fields in the Australian grain belt were intensively sampled to estimate population genetic parameters and the spatial aggregation, or clustering, of disease aggregates and genotypes. Estimates of population genetic parameters based on amplified fragment length polymorphisms (AFLPs) indicated that the genetic diversity in isolates from the 1-m-row populations described a significant portion of the diversity recorded for corresponding field and regional populations. In point pattern analysis, there was physical clustering and aggregation of F. pseudograminearum isolates from two of the three sites. Analysis of the spatial distribution of clonal haplotypes (DICE similarity ≥ 97%) indicated significant aggregation of clones in all three 1-m-row populations. Based on matrix comparison tests, both mating types and genetic distances had significant spatial aggregation for at least two of the three 1-m-row populations. This is consistent with the presence of non-random spatial genetic structure due to clonal aggregation. High levels of genetic diversity and spatial structuring of disease and genotypes in at least two of the three 1-m-row populations is consistent with the hypothesis that stubble is a primary inoculum source in no-tillage farming systems, resulting in aggregated patterns of disease and allowing for haplotypes to be maintained in the field over a number of annual cropping cycles.

Numerous pathogenic Fusarium species have well-characterized sexual cycles, whereas others, including the crown rot fungus F. pseudograminearum, do not. We conducted studies to elucidate the potential frequency and nature of sexual reproduction in field populations of F. pseudograminearum and developed tester strains for controlled crossings under laboratory conditions. Studies on the role of sexual recombination in the life cycle of F. pseudograminearum revealed apparently low levels of female fertility under controlled laboratory conditions, despite the observation of naturally occurring perithecia of the teleomorph Gibberella coronicola at two field sites. Female fertility levels were experimentally increased to produce female fertile tester strains using four generations of single and multi-stage crossings between sibling progeny derived from fertile laboratory crosses between field isolates collected in northeastern Australia. The production of reliable female fertile tester strains has potential applications for the construction of biological species boundaries, elucidation of the physical characters of reproductive structures, and the generation of genetic diversity via sexual recombination in F. pseudograminearum. As such, the current study is a significant advancement in the understanding of G. coronicola, allowing for future characterisation of various biological, epidemiological, and genetic parameters.

Microcera coccophila has been regarded as an entomopathogen of armoured scales in Australia since the late 1800s. We confirmed its identity and presence in Australia using morphological and molecular data. We also confirmed that a related species, M. larvarum, is an entomopathogen of armoured scales in Australia. M. coccophila was recorded as a parasite of Aonidiella aurantii, A. citrina, Lepidosaphes beckii, L. gloverii and Unaspis citri in citrus orchards on the Central Coast of New South Wales. We recorded M. larvarum in these orchards in association with A. aurantii and one or more hosts that could not be identified due to their condition. The sexual and asexual morphs of both species are described. Genetic variation suggested that the taxa could represent various phylogenetic species. We fulfilled Koch’s postulates for both fungi in separate bioassays with Aspidiotus nerii. Infection was not dependent on the reproductive status of the scale. A laboratory study showed that Iridomyrmex rufoniger, a common ant in Australian citrus orchards, can passively disperse conidia of M. coccophila. Field observations suggested that the prevalence of the two fungal parasites in orchards is influenced by host scale densities, climate, and foraging by I. rufoniger workers on honeydew produced by their sternorrhynchan trophobionts, particularly Saissetia oleae. These foraging activities induced dense populations of A. aurantii by disrupting the activities of the scale’s natural arthropod enemies; this was followed by epizootics of M. coccophila that decimated populations of the scale.

In May 2010 basal stem rot of snake bean (long bean) (Vigna unguiculata subsp. sesquipedalis) caused by Sclerotium rolfsii was discovered in Vientiane Capital, Lao PDR, during an ad hoc disease survey. The disease had resulted in death of some infected plants. The basal stem region had a bleached appearance, a typical symptom of this disease. Abundant small, round, brown sclerotia were present on the stem base, and on the adjacent soil and dead leaf material. The fungus was isolated into pure culture and Koch’s postulates were fulfilled. This is the first report of S. rolfsii in the Lao PDR, and the first report of basal stem rot of snake bean caused by this pathogen in the Lao PDR.

Rhizoctonia solani anastomosis group AG-4 HG-I is reported for the first time from the Lao PDR. It was isolated from gai lan (Brassica oleracea var. alboglabra )a ffected by collar rot, seedling death, root rot and stunting of older plants from the Paksong area of Champasak province. The anasto- mosis group was confirmed by sequencing and Koch' sp ostu- lates were fulfilled.

Cob rot epidemics occurred in NSW in sweet corn in 2002 and maize in 2003. Investigations were undertaken to establish the species of Fusarium associated with both instances. Dependent on region, F. verticillioides, F. proliferatum ,a ndF. subglutinans were isolated more fre- quently. The epidemics were unique in their occurrence being in two corn types, in consecutive years, and in two regions.

The genetic relationships of 56 isolates from the taxa traditionally grouped in Fusarium sections Fusarium (syn. Discolor ) and Roseum were studied using the Restriction Fragment Length Polymorphism (RFLP) technique, by Southern hybridisation with random genomic and mitochondrial DNA probes originating from Fusarium species. Pairwise distances between taxa were calculated from the 957 RFLP bands scored on autoradiograms, using Dice's coefficient in the RAPDistance computer program. A strong genetic relationship was observed between F. graminearum, F. culmorum and F. crookwellense . However, the morphologically similar taxon, F. pseudograminearum shared only approximately 40 % of genomic DNA RFLP bands with these taxa, demonstrating affinity, but less direct genetic similarity. Of all taxa examined F. pseudograminearum and F. graminearum shared the greatest similarity in mitochondrial DNA RFLP patterns. F. avenaceum subsp. avenaceum , subsp. aywerte and subsp. nurragi displayed very little genetic resemblance with each other, or with F. heterosporum and the cereal infecting pathogens. F. torulosum was closest genetically to subsp. avenaceum , with approximately 22 % of genomic DNA RFLP bands in common. On the basis of these results F. avenaceum subsp. aywerte and subsp. nurragi are elevated to species rank, as F. aywerte comb. nov. and F. nurragi comb. nov., and F. avenaceum subsp. avenaceum is returned to its former species status.

To test the hypothesis that climate is a major factor controlling the distribution of Fusarium species in soil, the effect of temperature on propagule density in soil and colonization of roots was determined experimentally. Five Fusarium species were inoculated together into untreated field soil in pots sown with perennial ryegrass. Changes in the density of propagules in soil recoverable by dilution plating and the proportion of roots colonized by each species were monitored over 12 months at three temperature ranges (13–18, 19–24 and 25–30°C). Propagule density of, and colonization of roots by, F. compactum and F. solani was greatest at higher temperatures (25–30°C). Fusarium torulosum demonstrated greatest colonization ability and propagule density in soil at lower temperatures (13–18°C). The propagule density of the cosmopolitan species F. equiseti remained high at all temperatures and this fungus successfully colonized plant roots under all conditions. While F. acuminatum did not compete well against the other species, the propagule density of this fungus was greatest at low temperatures. The differences in community structure resulting from differences in temperature in this model system mimicked those found when natural communities of Fusarium species are compared along climatic gradients.

Typical symptoms of pink root rot were observed in Chinese onions in Quang Nam and Nghe An provinces in Vietnam in 2007. The pathogen recognised as the cause of pink root rot in onions, Phoma terrestris, was isolated from diseased roots. This is the first report of pink root rot and P. terrestris in Vietnam.

Perithecia of Gibberella fujikuroi were found on old maize (Zea mays) stalks in northern Vietnam. Single ascospores from these perithecia produced cultures of the anamorph Fusarium moniliforme but ...

Fusarium babinda sp. nov. is described and illustrated. Fusarium babinda was isolated from soils and plant debris in soils associated with rainforest and wet sclerophyll forests in eastern Australia. The key features of this species are the formation of microconidia in proliferating polyphialides and the production of chlamydospores. Fusarium babinda can be distinguished from F. subglutinans by the presence of chlamydospores and the production of larger five-septate macroconidia, compared to three-septate macroconidia in F. subglutinans. The fungus is differentiated from F. polyphialidicum by the shape and nature of the macroconidium which is smaller and has thinner walls, the production of larger microconidia and the production of violet pigments in agar.

The climate analysis and prediction system BIOCLIM proved useful for collating distribution records, defining climate profiles for known distributions and predicting potential distributions within Australia of Fusarium spp. from soil. The potential range of F. acuminatum ssp. acuminatum was southern and eastern Australia, with its distribution limited by high temperatures. Fusarium acuminatum ssp. armeniacum was predicted to occur only in a limited higher rainfall, temperate area in south-eastern Australia, but climate may be only a secondary factor in determining its distribution. The potential range of F. compactum was most of mainland Australia except the southern coastal fringe and south-east highlands from which it was excluded by low temperatures. No significant climatic limits to the distribution of F. equiseti were found and its potential range was the whole of Australia. Fusarium longipes had a potential range in the higher rainfall areas of the tropics and subtropics, and it was excluded from other areas by low summer rainfall or low temperatures in the wet season. Fusarium scirpi had a potential range over most of temperate and arid Australia, but was excluded from areas that were too cold, where winter rainfall was more than twice the summer rainfall, and from the hot summer rainfall areas of the tropics.

Twenty-two Fusarium species as well as three undescribed populations were recovered from 42 sites representing three different climatic regions: Darwin (tropical), Alice Springs (arid) and Ceduna (mediterranean). These species were F. acuminatum subsp. acuminatum, F. anthophilum, F. avenaceum subsp. aywerte, F. beomiforme, F. chlamydosporum, F. compactum, F. dimerum, F. equiseti, F. graminearum Group 1, F. lateritium, F. longipes, F. merismoides, F. moniliforme, F. napiforme, F. nygamai, F. oxysporum, F. polyphialidicum, F. proliferatum, F. semitectum, F. scirpi, F. solani, F. subglutinans . Fifteen species were recovered from soils from the tropical region, 13 species and three undescribed populations from the arid region and seven species from the mediterranean region. Species found in all three regions were F. dimerum, F. equiseti, F. solani and F. oxysporum . Species recovered only from tropical soils were F. beomiforme, F. longipes, F. moniliforme and F. subglutinans. F. nygamai and F. scirpi were only recovered from arid soils; and F. a. acuminatum was only recovered from the mediterranean region. F. chlamydosporum and F. compactum were isolated frequently from soils in the tropical and arid regions but were more abundant in the arid soils from Alice Springs.

Comparison of survival and growth in culture of Fusarium acuminatum, F. compactum, F. equiseti and F. sambucinum at constant and fluctuating temperatures showed that F. compactum, abundant in hot arid regions, grew better and had higher survival rates at high temperatures than the other species. Fusarium acuminatum and F. sambucinum, which originated from temperate areas, had survival rates lower than the other two species when grown at elevated temperatures. Fusarium equiseti, a cosmopolitan species, was affected less by elevated temperature than were F. acuminatum and F. sambucinum, but was not as well adapted to hot arid regions as F. compactum.

Ten isolates each of Fusarium compactum and Fusarium acuminatum subsp. armeniacum were sub-cultured using single hyphal tips (HT) and single germinated macroconidia (SM) for ten generations. Cultural degeneration to intermediate, mycelial or pionnotal cultures was observed in a large proportion of cultures of both fungi, but pionnotal cultures were only produced in sub-cultures using SM transfers. Some reversion of intermediate and mycelial cultures to the wild type was observed. However, pionnotal cultures once formed were stable and did not revert to other cultural types in later generations. The toxicity and trichothecene production of degenerate cultures were comparable to those of wild type cultures. Colony diameters of pionnotal cultures were reduced in comparison with wild type cultures. The pigmentation of all degenerate cultures remained consistent with that observed in wild type cultures. Chlamydospore production was independent of cultural degeneration, as all cultural types produced chlamydospores equally well as the parental wild types.

Fusarium avenaceum subsp. aywerte subsp. nov. and Fusarium avenaceum subsp. nurragi subsp. nov. are described. F. avenaceum subsp. aywerte was isolated from grassland soils in central Australia, a hot arid region. F. avenaceum subsp. nurragi was isolated from heathland soil in south eastern Australia, a temperate region.

Fusarium oxysporum is an important plant and human pathogenic ascomycetous group, with near ubiquity in agricultural and non-cultivated ecosystems. Phylogenetic evidence suggests that F. oxysporum is a complex of multiple morphologically cryptic species. Species boundaries and limits of genetic exchange within this complex are poorly defined, largely due to the absence of a sexual state and the paucity of morphological characters. This study determined species boundaries within the F. oxysporum species complex using Genealogical Concordance Phylogenetic Species Recognition (GCPSR) with eight protein coding loci. GCPSR criteria were used firstly to identify independent evolutionary lineages (IEL), which were subsequently collapsed into phylogenetic species. Seventeen IELs were initially identified resulting in the recognition of two phylogenetic species. Further evidence supporting this delineation is discussed.

The Fusarium oxysporum species complex (FOSC) is a ubiquitous ascomycetous group that includes both pathogenic and non-pathogenic strains, the former being responsible for disease in over 100 cultivated plant species. Previous phylogenetic studies have uncovered at least four major clades within the FOSC, with Clade 1 hypothesised as being ancestral. However, the origin of these clades and pathogenic strains is poorly understood. Due to an emphasis on agricultural isolates in previous studies, the underlying diversity of this species complex in non-cultivated soils is largely unknown. To address this imbalance an extensive survey of isolates associated with native vegetation geographically isolated from cultivation throughout the Australian continent was conducted. A multi-gene phylogenetic analysis of the translation elongation factor (EF-1α) and the mitochondrial small subunit (mtSSU) rDNA loci did not recover any novel clades. However, the Australian isolates had high levels of intra-Clade diversity based on EF-1α sequence type (ST) comparison with a global dataset. The ST diversity was not equally distributed across the four clades, with the majority of novel STs recovered from Clade 1. Implications on the origin of the FOSC are discussed.