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Several key tree genera are used in planted forests worldwide, and these represent valuable global resources. Planted forests are increasingly threatened by insects and microbial pathogens, which are introduced accidentally and/or have adapted to new host trees. Globalization has hastened tree pest emergence, despite a growing awareness of the problem, improved understanding of the costs, and an increased focus on the importance of quarantine. To protect the value and potential of planted forests, innovative solutions and a better-coordinated global approach are needed. Mitigation strategies that are effective only in wealthy countries fail to contain invasions elsewhere in the world, ultimately leading to global impacts. Solutions to forest pest problems in the future should mainly focus on integrating management approaches globally, rather than single-country strategies. A global strategy to manage pest issues is vitally important and urgently needed.

The polyphagous shot hole borer (PSHB), an ambrosia beetle (Coleoptera: Curculeonidae: Scolytinae) native to Asia, together with its fungal symbiont Fusarium euwallaceae, has emerged as an important invasive pest killing avocado and other trees in Israel and the United States. The PSHB is one of three cryptic species in the Euwallacea fornicatus species complex, the taxonomy of which remains to be resolved. The surge in the global spread of invasive forest pests such as the PSHB has led to the development of programmes utilising sentinel tree plantings to record new host-pest interactions. During routine surveys of tree health in botanical gardens of South Africa undertaken as part of a sentinel project, an ambrosia beetle/fungal associate was detected damaging Platanus x acerifolia (London Plane) in the KwaZulu-Natal National Botanical Gardens, Pietermaritzburg. Identification of the beetle by sequencing part of the mitochondrial cytochrome oxidase c subunit 1 (COI) gene confirmed its identity as PSHB, and specifically one of the invasive haplotypes of the beetle. The associated fungus F. euwallaceae was identified based on phylogenetic analysis of elongation factor (EF 1-α) sequences. Koch’s postulates have confirmed the pathogenicity of fungal isolates to P. x acerifolia. This is the first report of PSHB and its fungal symbiont causing Fusarium dieback in South Africa. This report also represents the first verified case of a damaging invasive forest pest detected in a sentinel planting project, highlighting the importance of such studies. Given the potential impact these species present to urban trees, native biodiversity and agriculture, both the PSHB and its fungal symbiont should be included in invasive species regulations in South Africa.

A canker and wilt disease caused by the fungal pathogen Ceratocystis manginecans has devastated Acacia mangium plantations in Southeast Asia. The disease develops when the pathogen enters wounds of the stems of the trees. The wounds are caused by wind damage, branch pruning, animal feeding and borer infestation. Various insects, including nitidulid beetles and scolytine wood borers, have been shown to be closely associated with the development of this disease, although a vector relationship has not been established. The disease has never been found on the roots of trees and isolations from soil in heavily infested plantations have failed to yield cultures of C. manginecans. Research was initiated in 2012 has focused on developing an inoculation protocol to select A. mangium with tolerance to infection by C. manginecans. In order to achieve this, an isolate of the pathogen identified using DNA sequencing technology and having a high level of aggressiveness was selected. Preliminary trials showed that inoculations need to be conducted on established trees with welldeveloped vascular tissues, ideally one-year-old, and that tests on small plants are meaningless. The ideal inoculation technique involved inserting a single plug of C. manginecans mycelia into wounds made on the stems of one-year-old trees and monitoring the results during the subsequent 12 months, at which time most trees would have died. Over a period of approximately eight years, inoculations were performed on 6 000 such trees representing 140 A. mangium families. The small number of surviving trees was retained by grafting and subsequent vegetative propagation. Re-inoculation of these putatively tolerant trees has led to the identification of approximately 50 clones having high levels of disease tolerance. These trees can now be used to establish seed orchards and for hybridisation with Acacia auriculiformis, which is known to be substantially less susceptible to C. manginecans than A. mangium. The results suggest that it may be possible to pursue plantation forestry utilising A. mangium, most likely as a hybrid partner with A. auriculiformis.

BACKGROUND : Proteins in the Glycoside Hydrolase family 32 (GH32) are carbohydrate-active enzymes known as invertases that hydrolyse the glycosidic bonds of complex saccharides. Fungi rely on these enzymes to gain access to and utilize plant-derived sucrose. In fungi, GH32 invertase genes are found in higher copy numbers in the genomes of pathogens when compared to closely related saprophytes, suggesting an association between invertases and ecological strategy. The aim of this study was to investigate the distribution and evolution of GH32 invertases in the Ceratocystidaceae using a comparative genomics approach. This fungal family provides an interesting model to study the evolution of these genes, because it includes economically important pathogenic species such as Ceratocystis fimbriata, C. manginecans and C. albifundus, as well as saprophytic species such as Huntiella moniliformis, H. omanensis and H. savannae. RESULTS : The publicly available Ceratocystidaceae genome sequences, as well as the H. savannae genome sequenced here, allowed for the identification of novel GH32-like sequences. The de novo assembly of the H. savannae draft genome consisted of 28.54 megabases that coded for 7 687 putative genes of which one represented a GH32 family member. The number of GH32 gene family members appeared to be related to the ecological adaptations of these fungi. The pathogenic Ceratocystis species all contained two GH32 family genes (a putative cell wall and a putative vacuolar invertase), while the saprophytic Huntiella species had only one of these genes (a putative cell wall invertase). Further analysis showed that the evolution of the GH32 gene family in the Ceratocystidaceae involved transposable element-based retro-transposition and translocation. As an example, the activity of a Fot5-like element likely facilitated the assembly of the genomic regions harbouring the GH32 family genes in Ceratocystis. CONCLUSIONS : This study provides insight into the evolutionary history of the GH32 gene family in Ceratocystidaceae. Our findings suggest that transposable elements shaped the evolution of the GH32 gene family, which in turn determines the sucrolytic activities and related ecological strategies of the Ceratocystidaceae species that harbour them. The study also provides insights into the role of carbohydrate-active enzymes in plant-fungal interactions and adds to our understanding of the evolution of these enzymes and their role in the life style of these fungi.

Pitch canker, caused by the fungus Fusarium circinatum , is one of the most important pathogens of Pinus species. Sporadic outbreaks and epidemics caused by this fungus have been reported from numerous countries. Symptoms differ depending on the host species, geographical region, climatic conditions and associated insects. Pitch canker represents a significant threat to countries where non-native and susceptible Pinus spp. are grown intensively in plantations. A thorough understanding of the ecology and epidemiology of the causal agent is an important prerequisite to managing this threat. The aim of this review is to summarise contemporary knowledge relating to the pitch canker pathogen, with a particular focus on its threat to plantation forestry.

Acacia mangium plantations in Sabah, Malaysia are seriously affected by a vascular wilt and canker disease caused by a species of Ceratocystis. A similar and devastating disease occurs in Indonesia and is caused by the fungal pathogen Ceratocystis manginecans. A closely related fungus, Ceratocystis fimbriata sensu stricto, is a common soil-borne pathogen of sweet potato (Ipomoea batatas) in areas of Malaysia where A. mangium is grown. This study characterised the species causing wilting on A. mangium and compared it with the I. batatas pathogen using DNA sequence-based comparisons used artificial inoculations to assess the effect of the A. mangium pathogen on Acacia auriculiformis and Acacia crassicarpa and considered the ability of the sweet potato pathogen to cause disease on the three Acacia species. DNA sequence comparisons confirmed that isolates from diseased A. mangium were C. manginecans and those on sweet potato were C. fimbriata s.s. Ceratocystis manginecans was pathogenic on all Acacia spp., with A. mangium being most susceptible followed by =A. auriculiformis and A. crassicarpa. Pathogenicity tests showed that C. fimbriata s.s. from sweet potato is not able to cause disease on any of the three Acacia spp. considered. This study also confirmed that C. manginecans is the primary cause of ceratocystis canker and wilt disease in Sabah and that the sweet potato fungus, C. fimbriata s.s., poses no threat to propagated Acacia spp.

The Ophiostomatales (Ascomycota) include mainly insect and mite-associated fungi, the majority of which are found on trees. Very little is known regarding the occurrence or diversity of these fungi in South America. The aim of this study was to consider their occurrence on native Nothofagus trees in the Patagonian Andes of Argentina. Isolates were collected in national parks and provincial reserves in Patagonia between 2009 and 2011. These were grouped based on morphology, and 22 representative isolates were included in phylogenetic analyses based on sequence data of multiple loci (LSU, ITS, beta-tubulin and translation elongation factor-1 alpha genes). The isolates could be assigned to ten different taxa, and included eight species of Ophiostoma s. l., one species of Leptographium, and one species in the Sporothrix lignivora complex. Three of the species are described as new, including Ophiostoma patagonicum, Leptographium gestamen, and Sporothrix cabralii. Ophiostoma quercus and O. noveae-zelandiae are reported for the first time from Argentina, and we show that the latter species is distinct from O. pluriannulatum, in contrast to a previous suggestion that they represent the same taxon.

Ceratocystis canker and wilt disease has had a devastating impact on plantations of Acacia mangium in Sabah, Malaysia effectively resulting in its discontinuation in the region. The immediate future of industrial tree plantations in Malaysia relies on alternative species, such as Eucalyptus pellita, which are suited to the environment and market opportunities. However, identifying A. mangium planting stock with high levels of tolerance to Ceratocystis manginecans provides substantial opportunities for its large scale planting and sustainability in the future. The aim of this study was to verify tolerance to C. manginecans in over 100 putatively tolerant A. mangium clones selected from a family screening trial consisting of 100 wild families. Selections from the family screening trial were based on either short-lesion length measured six weeks after inoculation or survival 12 months post inoculation. Six clonal trials were established under field conditions over two years with more than five ramets of most clones tested in at least two separate trials. The trees were inoculated with C. manginecans 12 months after trial establishment, and assessments of crown health and survival as well as the presence or absence of sunken bark, gummosis or stem borer infestation were carried out 12 months post inoculation. Narrow-sense heritability estimates were moderate for external variables and for crown health (0.14–0.24) and survival (0.14–0.22). Genetic correlation estimates between trials were generally high, indicating that assessments were repeatable across trials. Correlations between traits used to assess damage following inoculation indicated that different traits may be used to identify clones that tolerate infection. The accuracy of the screening showed that resistant clones can be identified and used to produce A. mangium tolerant to infection by C. manginecans.

Botryosphaeria rhodina (anamorph Lasiodiplodia theobromae) is a common endophyte and opportunistic pathogen on more than 500 tree species in the tropics and subtropics. During routine disease surveys of plantations in Australia and Venezuela several isolates differing from L. theobromae were identified and subsequently characterized based upon morphology and ITS and EF1-alpha nucleotide sequences. These isolates grouped into three strongly supported clades related to but different from the known taxa, B. rhodina and L. gonubiensis, These have been described here as three new species L. venezuelensis sp. nov., L. crassispora sp. nov. and L. rubropurpurea sp. nov. The three could be distinguished easily from each other and the two described species of Lasiodiplodia, thus confirming phylogenetic separations. Furthermore all five Lasiodiplodia spp. now recognized separated from Diplodia spp. and Dothiorella spp. with 100% bootstrap support.Botryosphaeria rhodina (anamorph Lasiodiplodia theobromae) is a common endophyte and opportunistic pathogen on more than 500 tree species in the tropics and subtropics. During routine disease surveys of plantations in Australia and Venezuela several isolates differing from L. theobromae were identified and subsequently characterized based upon morphology and ITS and EF1-alpha nucleotide sequences. These isolates grouped into three strongly supported clades related to but different from the known taxa, B. rhodina and L. gonubiensis, These have been described here as three new species L. venezuelensis sp. nov., L. crassispora sp. nov. and L. rubropurpurea sp. nov. The three could be distinguished easily from each other and the two described species of Lasiodiplodia, thus confirming phylogenetic separations. Furthermore all five Lasiodiplodia spp. now recognized separated from Diplodia spp. and Dothiorella spp. with 100% bootstrap support.

Integrated pest management (IPM) is difficult to implement when one knows little about the pest complex or species causing the damage in an agricultural system. To implement IPM on Sub-Saharan African melolonthine pests access to taxon specific knowledge (their identity) and what is known (their biology) of potential pest species is a crucial step. What is known about Sub-Saharan African melolonthine white grubs and chafers has not yet been amalgamated, and this review thus synthesizes all available literature for the Region. The comprehensive nature of the review highlights pest taxon trends within African melolonthines. To facilitate the retrieval of this information for IPM purposes, all relevant taxonomic and biological information is provided for the taxa covered including an on-line supplementary annotated-checklist of taxon, crop, locality and reference(s). Based on the literature reviewed, recommendations are made to promote effective and efficient management of African melolonthine scarab pests. An on-line supplementary appendix provides a list of specialists, useful internet resources, keys, catalogues and sampling methods for the larvae and adults of melolonthine scarab beetles for subsequent morphological or molecular work.