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Next-generation sequencing (NGS) has revolutionized research on fungi including Botryosphaeriaceae, a family of important plant and particularly tree pathogens. This review highlights the impact that NGS-generated genomes and transcriptomes have had on our understanding of the biology and evolution of these fungi. In less than a decade, 49 genomes representing 31 species in eight genera have been published for the Botryosphaeriaceae. These genomes have been used to show that species in this family are capable of sexual reproduction and that the evolution of their mating strategy is highly dynamic, due to multiple independent transitions from a heterothallic ancestral state to homothallism. Comparative genomics has further revealed an abundance of genes involved in infection and aggressiveness. These include plant cell wall-degrading enzymes and secondary metabolite biosynthetic genes as well as genes related to detoxification and cellular transport. Transcriptomics studies have shown that gene expression is tightly regulated and that there are often significant changes in gene expression occurring between early and late infection and as a response to environmental stress. Furthermore, the genomes of species in the Botryosphaeriaceae do not present genomic architecture compartmentalization based on gene and repeat density. Rather, gene organization patterns are influenced by gene co-expression patterns. NGS data have also made possible the development of molecular markers for some species and these can now also be used for species lacking genomic data. The growth of NGS platforms and their integration with other emerging technologies promises an even deeper understanding of the biology and evolution of the Botryosphaeriaceae and other plant pathogens. This will continue to promote and will also revolutionize the field of plant pathology. • The number of Botryosphaeriaceae genomes and transcriptomes has increased rapidly • This provided insights into the biology and evolution of Botryosphaeriaceae • This family has undergone multiple transitions from heterothallism to homothallism • Botryosphaeriaceae genomes are rich in hydrolytic enzymes, toxins and transporters • Transcription changes between infection stages and environmental conditions [ABSTRACT FROM AUTHOR]

Unisexuality in fungi is the result of sexual reproduction in a single isolate that harbors genes associated with only a single mating type. To date, unisexual reproduction has been described in only three genera of filamentous fungi. Consequently, our understanding of this unusual pathway is limited. In this critical review, we compare genetic, genomic and transcriptomic data from a variety of unisexual species to similar data from their primary homothallic and heterothallic relatives. These analyses show that unisexual reproduction is likely derived from heterothallism via the mutation of genes involved in the initiation of sexual reproduction. We show that significant changes in mating-type genes, pheromone precursor genes and pheromone receptor genes are common in unisexual species, but that similar changes are not evident in their primary homothallic or heterothallic relatives. These findings are particularly notable because the unisexual species are accommodated in unrelated genera, illustrating that a similar transition to unisexuality has likely occurred independently in their lineages. [ABSTRACT FROM AUTHOR]

Highlights • Maternal environment can influence the relative growth rate of the progenies. • Physiology of Eucalyptus grandis offspring was affected by maternal environment. • Plant intercellular CO 2 was influenced by maternal environment. • Intrinsic water use efficiency differed depending on the maternal environment. Abstract The phenotype of a plant can be shaped by the biotic and abiotic conditions to which their parents are subjected. This phenotypic plasticity known as maternal environmental effect occurs regardless of the changes in the DNA sequences. Whereas the effect of the maternal environment on plant phenotype has been studied, its specific influence on plant physiology is less clear. This study considered the influence of the maternal environment on the regulation of plant morphology and physiology in progeny of Eucalyptus grandis. Plants were grown from seeds collected from two E. grandis clonal seed orchards that differed in environmental conditions (e.g. precipitation). Plant relative growth rate (RGR), leaf gas exchange and water use efficiency (WUE) were measured in the seedlings. RGR was 10% higher in the offspring from the maternal environment receiving higher precipitation levels. Leaf gas exchange, specifically leaves intercellular CO 2, and intrinsic WUE were also influenced by maternal environments. Intrinsic WUE was significantly lower in the orchard that received lower precipitation levels. The results demonstrate that the maternal environment can regulate the physiology of E. grandis in the subsequent generation. These analyses are useful to optimise tree improvement in a changing environment. Moreover, in a scenario of climate change, maternal environmental effects may be a crucial mechanism for certain species to get acclimated to sudden changes in environmental conditions. [ABSTRACT FROM AUTHOR]

Abstract The diversity of Phytophthora species associated with various ecological niches is poorly understood. In this study, the community composition and distribution of Phytophthora species associated with non-native plantation trees, Eucalyptus grandis and Acacia mearnsii, was compared with adjacent natural forests in South Africa using soil baiting and metabarcoding approaches. Through soil baiting, 85 Phytophthora isolates were recovered representing five taxa: P. alticola , P. cinnamomi, P. frigida, P. multivora and P. pseudocryptogea. Metabarcoding revealed molecular operational taxonomic units corresponding to 32 Phytophthora taxa. Among these, 14 were new reports from South Africa, including seven undescribed taxa. The community composition of Phytophthora species clustered according to vegetation type. Most species in plantations were present in the natural forest sites, but few species were exclusively associated with the non-native plantations. Overall, the results revealed a substantial diversity of Phytophthora species that includes both described and novel phylotypes previously unknown from South Africa. [ABSTRACT FROM AUTHOR]

Recent scientific and technological advances have improved and streamlined our ability to recognise and describe fungal species. Detailed comparative genomics studies have also expanded our understanding of species boundaries. Against this background, we explore the nature of fungal species and consider how this impacts our understanding of their genetics and evolution. The current body of evidence suggests that fungal species are unique evolutionary units that are separated from one another by boundaries that are “porous” under certain conditions (“semipermeable” in analogy to the differential permeability of membranes). Overall, the penetrability of these boundaries depends on the relatedness between donor and recipient species, the spatial proximity of related species to one another during their evolution, and the evolutionary potential associated with the breach of a boundary. Furthermore, the semipermeable nature of species boundaries fundamentally affects the population genetics of a species, with potentially profound effects on its overall evolution and biology. This also influences the methodologies used in taxonomy, because some species appear capable of maintaining their genetic isolation despite extensive penetrability of their boundaries. Most analytical procedures are also not able to distinguish the signals of species boundary permeability from those associated with incomplete lineage sorting or intraspecific diversity. Collectively, these issues greatly complicate how we study and name fungi. An awareness of the nature of species, their boundaries and the biological and genomic signatures of boundary breaches, will enhance our ability to identify them and, perhaps more importantly, to develop realistic strategies to manage and manipulate their growth and distribution. [ABSTRACT FROM AUTHOR]

A unique microbiome occurs within the flower heads of various Protea species endemic to Africa. These include two lineages of ophiostomatoid fungi, Knoxdaviesia (Microascales) and Sporothrix (Ophiostomatales), that have members occurring exclusively in this environment and that rely on mites as their primary mode of spore dissemination. The mites, in turn, attach to the bodies of Protea -pollinating beetles and the beaks and bodies of birds for long-distance movement, establishing a hierarchical dispersal network for the ophiostomatoid fungi. This inter-organismal network is highly successful, achieving fungal dispersal over vast distances. Multiple species of fungi, mites and bacteria have been described from this unique niche over the past four decades. The intricacies of their symbiotic interactions continue to be unravelled. This review covers all current knowledge of the "distinctly African" Protea -ophiostomatoid fungus environment and illustrates the depth of a fascinating unseen fungal biodiversity niche. [Display omitted] • Two lineages of ophiostomatoid fungi occur exclusively in Protea flower heads. • Mites act as primary spore vectors and are phoretic on other arthropods and birds. • Recombination and hierarchical dispersal facilitate massive genetic diversity. • Early colonisation and niche differentiation likely alleviate interspecific competition. • Insights from this fungal niche benefit biodiversity and plant health research. [ABSTRACT FROM AUTHOR]

Protea -associated Knoxdaviesia species grow on decaying inflorescences, yet are closely related to plant pathogens such as Ceratocystis albifundus . C. albifundus also infects Protea , but occupies a distinct niche. We investigated substrate utilization in two Knoxdaviesia saprotrophs, a generalist and a specialist, and the pathogen C. albifundus by integrating phenome and whole-genome data. On shared substrates, the generalist grew slightly better than its specialist counterpart, alluding to how it has maintained its Protea host range. C. albifundus grew on few substrates and had limited cell wall-degrading enzymes. It did not utilize sucrose, but may prefer soluble oligosaccharides. Nectar monosaccharides are likely important carbon sources for early colonizing Knoxdaviesia species. Once the inflorescence ages, they could switch to degrading cell wall components. C. albifundus likely uses its limited cell wall-degrading arsenal to gain access to plant cells and exploit internal resources. Overall, carbon metabolism and gene content in three related fungi reflected their ecological adaptations. [ABSTRACT FROM AUTHOR]

Filamentous fungi in the subdivision Pezizomycotina (Ascomycota) display an impressive diversity of mating strategies. These mating systems are all controlled by the mating-type ( MAT ) genes, some of which are conserved, even among distantly related genera. In order to facilitate effective communication between researchers, a system was established in 2000 to name these genes and this has subsequently been widely applied. However, due to the rapid growth in the number of described MAT genes in the Pezizomycotina, an evaluation of the manner in which the nomenclature system has been applied is warranted and revisions should be considered. We address this challenge by doing a systematic review of the nomenclature associated with the MAT1 locus and its associated genes described in the Pezizomycotina. Several problems in the application of the nomenclature system were identified and addressed. These included proposed revisions of the nomenclature system to provide a more accurate description of the mating-type genes. We anticipate that this review will reduce confusion and that it will be useful in future characterisation of mating-type genes. [ABSTRACT FROM AUTHOR]

Metacommunity theory offers a powerful framework to investigate the structure and dynamics of ecological communities. We used Ceratocystidaceae fungi as an empirical system to explore the potential of metacommunity principles to explain the incidence of putative fungal tree pathogens in natural ecosystems. The diversity of Ceratocystidaceae fungi was evaluated on elephant-damaged trees across the Kruger National Park of South Africa. Multivariate statistics were then used to assess the influence of landscapes, tree hosts and nitidulid beetle associates as well as isolation by distance on fungal community structure. Eight fungal and six beetle species were recovered from trees representing several plant genera. The distribution of Ceratocystidaceae fungi was highly heterogeneous across landscapes. Both tree host and nitidulid vector emerged as key factors contributing to this heterogeneity, while isolation by distance showed little influence. Our results are consistent with a model of metacommunity dynamics combining species sorting and patch dynamics processes. [ABSTRACT FROM AUTHOR]

The Botryosphaeriaceae are opportunistic pathogens mostly of woody plants, including Eucalyptus . These fungi can cause cankers and die-back diseases on non-native Eucalyptus trees in South African plantations. Botryosphaeriaceae were isolated from diseased and asymptomatic twigs and leaves from 20 Eucalyptus spp. grown in a Pretoria, South Africa arboretum and its surroundings. The isolates were initially grouped based on conidial morphology and Internal Transcribed Spacer (ITS) rDNA PCR-RFLP profiles. They were further identified using DNA sequence data for the ITS rDNA and translation elongation factor 1-α (TEF-1α) gene regions and tested for pathogenicity. Five species were identified including Botryosphaeria dothidea and four Neofusicoccum species namely Neofusicoccum parvum ; N. cryptoaustrale and N. ursorum that were recently described from plant tissues collected as a part of the current study; and Neofusicoccum eucalypti (Winter) Maleme, Pavlic & Slippers comb. nov. The latter species is recorded for the first time on Eucalyptus in South Africa. Most of the identified species were collected from the leaves of 17 different Eucalyptus spp. Neofusicoccum parvum was most commonly isolated (72% of all isolates) followed by B. dothidea species complex (17%). With exception of N. parvum which was isolated from majority of Eucalyptus spp. the other species were isolated from limited number of Eucalyptus species indicating host-preferences. All the isolated Botryosphaeriaceae species produced lesions on inoculated Eucalyptus grandis plants that were significantly larger than those associated with the controls. [ABSTRACT FROM AUTHOR]

Knoxdaviesia and Sporothrix species occupy the flower heads of some Protea plants in southern Africa. Knoxdaviesia species display exceptional genetic diversity within the Core Cape Subregion (CCR) and are readily dispersed across large distances. This study aimed to determine whether overlapping ecologies have led to a similar population genetic structure in Sporothrix splendens. Two DNA sequence markers, β-tubulin and a microsatellite region, were amplified in 97 S. splendens strains from eight populations that span its host distribution. Genetic diversity was low in a geographically isolated population, but high elsewhere. CCR populations were closely related, showing isolation by distance with populations at the eastern edge of the sampling range. Like Knoxdaviesia species, long-distance dispersal of S. splendens spores is prevalent, although likely affected by patchy host populations. This study is the first to consider populations of a non-clinical Sporothrix species, providing insights into the population attributes of a naturally distributed species. • This is the first population level study of a non-clinical Sporothrix species. • Most populations of S. splendens in Protea repens are closely related and diverse. • Long distance dispersal enables regular gene flow among S. splendens populations. • Geographic isolation of P. repens populations affects fungal population structure. • S. splendens genetic structure corresponds with that of Knoxdaviesia species. [ABSTRACT FROM AUTHOR]

• Eucalyptus soil microbiome data showed fungal diversity, comprised of pathogens and symbionts of the tree. • Fungal species richness differed significantly between the three post-harvest soil treatment regimes. • The soil fungal community was influenced by the post-harvest residue management regimes and the location of the plantation sites. • Plots retaining post-harvest trimmings had the highest species richness of beneficial fungi, such as saprotrophs and symbiotrophs. • Application of fertiliser also increased the biodiversity of soil fungi at our study sites. Plantation forests have the potential to meet global economic and ecological objectives. The sustainability of plantations is influenced by a variety of above- and below-ground factors. Among these factors are soil-associated microbes, as they play a vital role in soil biogeochemical processes. However, when compared to natural forests, the microbial biodiversity associated with plantation soils is often less biodiverse due to anthropogenic disturbances. The loss of microbial biodiversity in plantation soils can be partially mitigated through better post-harvest residue management regimes. To study this hypothesis in South African plantation soils, the effects of three post-harvest residue management regimes on fungal diversity were compared: retained, removed, or removed and fertilized. We collected 108 soil samples from these treatments at three study sites planted with a single Eucalyptus genotype. Consequently, DNA was extracted from all soil samples and fungal amplicon libraries were constructed using the Illumina MiSeq platform. The bioinformatic and statistical analyses of the data indicated that the post-harvest residue management regimes, the location of the study sites, and their interaction (soil treatment × site) influenced the community composition of soil fungi. The plots retaining post-harvest residues had a higher diversity of saprotrophs and symbiotrophs and fewer pathotrophs. The results showed that retaining post-harvest residue can improve the diversity of beneficial soil fungi in South African plantation soil. In the future, the South African and global forestry sectors should consider retaining post-harvest residues to ameliorate the tree and soil health of their plantations. [ABSTRACT FROM AUTHOR]

This paper focuses on an analysis of planted forests data from the 2015 Forests Resources Assessment of the U.N. Food and Agriculture Organisation (FRA 2015). It forms one of a series of papers in the FRA 2015 special issue of this journal. While total forest area decreased from 4.28 billion hectares to 3.99 billion hectares from 1990 to 2015, with percent global forest cover dropping from 31.85% to 30.85%, the area of planted forests increased from 167.5 to 277.9 million hectares or 4.06% to 6.95% of total forest area. Increase was most rapid in the temperate zone, and regionally in East Asia, followed by Europe, North America, and Southern and Southeast Asia. However the annualised rate of increase in area of planted forests slowed in the 2010–2015 period to 1.2%, below the 2.4% rate suggested is needed to supply all of the world’s timber and fibre needs. The majority of planted forests comprised native species with only 18–19% of the total area being of introduced species. Introduced species were dominant in the southern hemisphere countries of South America, Oceania and Eastern and Southern Africa where industrial forestry is dominant. Twenty countries accounted for 85% of planted forest area and a different 20 countries for 87% of planted forest roundwood supply. As with forest area, roundwood supply from planted forests also showed an increasing trend although this was based on minimal data. There was a mismatch in composition and rankings of the top 20 countries with top forest area and roundwood production suggesting that there are substantial opportunities to increase roundwood production in the future, especially in China which has the largest area but is currently ranked 3rd in roundwood production. Outlook statements were developed for the FAO sub regions based on past changes in planted forest area, population growth, and climate and forest health risks to identify key issues for the future. The overall view from this study suggests that climate impacts, especially from extreme climatic events will affect planted forests in the future and that forest health impacts can also be expected to increase. Outlooks vary regionally. Europe and North America are likely to be most concerned with climate and health risks; Asia will experience population pressure that will impact on land availability for new forests and risks from extreme weather events, and will need to make the most of its existing forests; Africa will need to increase planted forest area to offset continuing deforestation and rapid population growth; and Oceania, the Caribbean, Central and South America are likely to be most concerned with climate impacts. To ensure the continued contribution of planted forests, a number of responses will be required to both maintain existing and also to develop new forests. Intensification of production in existing forests will lessen the need for greater forest areas and offset any land use conflicts related to food security; climate adaptation strategies will need to be developed as a matter of urgency, and forest health focus must remain a priority for research. Establishment of new forests will be eased through greater community and stakeholder engagement. Application of models such as WWF’s New Generation Plantations, which recognises the importance of society and the need to consider the full range of forest products and services within the wider landscape and spectrum of land uses, will be important. We recommend that to enable deeper analysis related to planted forests future FRA Assessments consider ways to better gather data specific to planted forests such as productivity so that this important component of global forests can be better understood. [ABSTRACT FROM AUTHOR]

Coniferous trees can suffer significant damage from seedling diseases caused by Fusarium spp. and from pitch canker, which is caused by Fusarium circinatum Nirenberg & O'Donnell. These fungi can be responsible for both pre- and post-emergence damping-off, and latent infections can result in failure of transplanted seedling to become established. Fusarium oxysporum Schlechtend.: Fr. has long been recognized as the most important cause of root and hypocotyl rot in seedling nurseries, but phylogenetic analysis suggests that the most virulent strains are more properly assigned to the recently described Fusarium commune Skovgaard, O'Donnell et Nirenberg. Management of Fusarium diseases in bare-root seedling nurseries has relied primarily on preplant soil fumigation. Because regulations will increasingly limit availability of the most efficacious fumigants, alternative management practices are being explored. This includes greater attention to sanitation, maintaining a robust microbial community that will inhibit root-infecting pathogens and avoiding practices that predispose trees to disease, such as excessive fertilization and poorly drained soils. F. circinatum Nirenberg & O'Donnell can be a problem in seedling nurseries but is also damaging to mature trees in plantations, seed orchards, landscape plantings, and native forests. A critical element of management is limiting spread of disease from existing infestations. To this end, branches and logs removed from infected trees should be disposed of locally. Seeds and seedlings can both carry the pathogen and so should not be moved from infested to non-infested areas. Quarantine restrictions should be maintained to prevent introduction of F. circinatum into countries where it is not yet established. Infections caused by F. circinatum are associated with wounds resulting from silvicultural practices, such as pruning and seed harvesting, weather related injuries and insect activity. In managed plantings, the risk of disease can be reduced by limiting pruning operations to cool, dry periods, which are less conducive to infection, and by judicious control of insects that can serve as wounding agents and vectors. Variation in susceptibility to pitch canker has been documented in a number of commercially important pine species, offering the prospect for greater utilization of genetic resistance for management of this disease in the future. [ABSTRACT FROM AUTHOR]

The Botryosphaeriaceae are common and diverse members of fungal communities infecting woody plants. They are also increasingly being used as model organisms to understand patterns in the global movement of latent pathogens. The aim of this study was to consider the species richness of the Botryosphaeriaceae associated with the native Acacia ( Vachellia ) karroo across South Africa, and the variation of species at specific local sites over time. The diversity of these fungi associated with different tissues of this host plant was also considered. These questions were addressed by sampling healthy A. karroo from 23 sites in South Africa and by more intensive hierarchical sampling conducted at 40 sites in one area over 3 yr. In total, 13 species of the Botryosphaeriaceae were identified, including seven that were isolated only from the more intensively sampled area. There was a clear geographical influence, with some species occurring only in some parts of the country. Significant variation in the species richness over time for the intensively sampled area was found and there was no evidence of tissue specificity for this group of fungi in leaves, branches and branchlets. Results of pathogenicity trials showed highly variable lesion sizes for the isolated species in comparison to the control, with Sphaeropsis variabilis , Lasiodiplodia theobromae and Neofusicoccum australe being the most pathogenic. The overall results revealed a rich diversity of Botryosphaeriaceae on this native host, which varied significantly both geographically and on individual trees, even in the absence of obvious disease. [ABSTRACT FROM AUTHOR]

Plants and animals adapted to colonize disturbed sites might also be better invaders, but this phenomenon has not been widely considered in fungi. We investigated genetic diversity and structure amongst isolates of Neofusicoccum parvum , N. cordaticola , N. kwambonambiense and N. umdonicola that coexist sympatrically on a native tree, Syzygium cordatum , across its distribution in South Africa. Species composition varied among stands, with dominance of N. parvum in disturbed stands, and absence in undisturbed stands, where the other species dominated. N. parvum populations from trees planted in urban environments were more genetically diverse than populations from human disturbed stands of S. cordatum . Bayesian analysis clustered N. parvum isolates in three sub-populations, suggesting three sources of origin. These results support the hypothesis that as a generalist N. parvum will dominate human disturbed sites and trees in urban areas, indicating strong potential for invasion, and its spreading from non-native hosts to native S. cordatum , rather than vice versa . [ABSTRACT FROM AUTHOR]

Abstract: Plantation forestry based on Eucalyptus spp. has grown dramatically during the past 100years, mainly in the tropics and southern hemisphere where these trees are non-native. Early plantations were affected by pests and pathogens, although damage was generally minimal. This is a situation that is changing dramatically with serious pest and pathogen problems now emerging regularly and often times causing very serious damage. Given the growing movement of people and products around the world, this is a trend that is certain to continue and the threat of diseases and insect damage is now seen as one of the most important constraints to the future sustainability of Eucalypt plantation forestry globally. While this is a very troubling situation, there are also reasons to be optimistic. Established technologies such as breeding and selection of disease and insect resistant species and hybrids; enhanced through vegetative propagation have already shown substantial promise to reduce damage. Likewise, biological control is being effectively used to reduce damage due to invasive alien insect pests. New technologies including DNA-based tools for identification, detection and monitoring of pest and pathogens are increasingly valuable. Similarly, the growing availability of genome sequences for Eucalypts and for their pests and pathogens will increasingly add to our capacity to reduce damage. While there are unknown dangers such as the impact of climate change on the damage caused by pests and pathogens, we believe that continual and realistic investment in technology will ensure long term sustainability of Eucalypt plantation forestry. Failure to invest wisely will result in the collapse of plantation enterprises and concomitant loss in investments. [Copyright &y& Elsevier]

Abstract: In many respects, the ecology of members of the Botryosphaeriaceae compare to general patterns observed for the collective of endophytes of woody plants. These include high levels of diversity, horizontal transmission a spatial structure and a continuum of levels of host affinity from specific to very broad. Some members of the Botryosphaeriaceae are, however, among the most aggressive pathogens in the assemblages of common endophytic fungi, often killing large parts of their host, following physical damage or general stress on the host (and over large areas). Their wide occurrence, the latent phase which can be overlooked by quarantine, and their ability to rapidly cause disease when their hosts are under stress, make these fungi a significant threat to agricultural, plantation and native forest ecosystems alike. This is especially relevant under emerging conditions of dramatic climate change that increases stress on plant communities. It is, therefore, important to maximize our understanding of the ecology and pathology of the Botryosphaeriaceae, particularly as it relates to their endophytic nature, species richness, host switching ability and the host-fungus-environment interaction. [Copyright &y& Elsevier]

The ascomycete genera Cryphonectria and Endothia are closely related members of Diaporthales. Recent DNA sequence comparisons have shown that isolates from Elaeocarpus spp. in New Zealand, previously identified as Cryphonectria radicalis and Cryphonectria gyrosa, represent a phylogenetic group distinct from those including other species of Cryphonectria and Endothia. Cryphonectria gyrosa applies to a species that occurs on Elaeocarpus glandulifer in Sri Lanka, the same host genus but a different species from which the New Zealand collections were made. The aim of this study was to provide a name for the fungi residing in the phylogenetic group from New Zealand. Morphological characters that define these fungi include superficial conical conidiomata, conidia of variable size, and ascospores with one to three septa. These characteristics are not found in other species of Cryphonectria. We also recognise a second species in the group from New Zealand that has distinctly larger ascospores. Herbarium specimens of C. gyrosa exhibit the same primary characteristics as the specimens from New Zealand and C. gyrosa is regarded as conspecific with one of the species in the New Zealand collections. A new genus, Amphilogia, is described for the collections of C. gyrosa from Sri Lanka and New Zealand, which also contains the second species from New Zealand, Amphilogia major sp. nov. [ABSTRACT FROM AUTHOR]

Pathogens, pests and diseases impact heavily on commercial plantation forestry in South Africa, and must thus be considered in any diversified and adaptive management approach. Two important fungal pathogens of Pinus and Eucalyptus species, respectively, are Sphaeropsis sapinea and Cryphonectria cubensis. The aim of this study was to explore the use of bioclimatic modelling to predict the habitat distribution for these pathogens, and to consider potential distribution patterns under conditions of climate change. High-risk areas identified for Sphaeropsis dieback coincide with the summer rainfall hail belt, emphasising the need for planting resistant Pinus spp. in these regions. A much smaller area of South Africa is predicted to be suitable for the occurrence of C. cubensis than for S. sapinea, but a range shift westward in suitable habitat for C. cubensis is predicted under a climate change scenario. Of concern is that many of these areas are currently being planted with disease susceptible Eucalyptus clones. These preliminary results, and further refinement of the model, will lay a valuable foundation for future risk assessment and strategic management planning in the South African forestry industry. [Copyright &y& Elsevier]

Eucalyptus spp. are planted in many parts of the world for the production of timber and pulp, and in South Africa, they form a major component of the forestry industry. The canker pathogen, Cryphonectria eucalypti, is pathogenic to Eucalyptus spp. in Australia and Tasmania and occurs in all of the major Eucalyptus growing areas of South Africa. This study was undertaken to consider the pathogenicity of C. eucalypti to Eucalyptus clones in South Africa. Fifteen isolates of C. eucalypti were initially screened for their virulence on a susceptible Eucalyptus grandis clone (ZG14) in the field. A plot consisting of 42 different clones of Eucalyptus was subsequently challenged with a selected virulent isolate of C. eucalypti to determine whether clones differ in their tolerance to the pathogen. Results showed that C. eucalypti is capable of causing significant lesions on Eucalyptus clones and that disease development is strongly dependent on environmental factors. All of the clones tested were susceptible to C. eucalypti, but exhibited varying levels of tolerance to the pathogen. [Copyright &y& Elsevier]

Sphaeropsis sapinea is an opportunistic pathogen of Pinus spp. and other conifers. Infection occurs when host trees are predisposed by adverse environmental conditions or mechanical damage. Initially two morphotypes, A and B, were described for S. sapinea and these were defined based on cultural characteristics, texture of conidial walls and virulence. The existence of these two morphotypes has, furthermore, been confirmed through the use of RAPDs and DNA sequencing of the ITS region of the rRNA operon. A third RAPD group, including isolates from Indonesia and Mexico, has recently been reported and was designated as a C morphotype based on differences in conidial size. The objective of this study was to characterise isolates of the C morphotype of S. sapinea based on cultural characteristics, conidial morphology, growth rate and pathogenicity. Cultural and conidial characteristics of isolates belonging to the A and C morphotypes were more similar to each other than to those of the B morphotype. The growth rates of isolates belonging to the three different morphotypes were not significantly different. Artificial inoculation of both Granny Smith apples and Pinus patula seedlings revealed that isolates of the C morphotype were considerably more virulent than those of the A and B morphotypes. The discovery of the more virulent C morphotype of S. sapinea could have serious implications for management of this pathogen, as well as quarantine practises in countries that import pine seeds. [Copyright &y& Elsevier]