Diseases of Eucalypts in Paraguay and First Report of Teratosphaeria zuluensis from South America

Background and objectives: The global forest economy is threatened by eucalypt pathogens which are often latent or cryptic species that escape common quarantine and detection methods. Plantation forestry using eucalypts is of considerable importance to Paraguay, but knowledge regarding the pests and diseases affecting these plantations is limited. This study identified fungal diseases present in these plantations. Materials and Methods: We surveyed eucalypt plantations in four provinces in Paraguay and collected material from diseased trees for identification of the causal agents. The samples were analyzed using a combination of morphological and molecular methods. Results: Diseases encountered included Botryosphaeria stem canker, Calonectria leaf blight, Chrysoporthe stem canker, myrtle/eucalypt rust, Coniella leaf spot, heartwood rot and Teratosphaeria stem canker. Contrary to expectations, the causal agent of Teratosphaeria stem canker was identified as Teratosphaeria zuluensis (M.J. Wingf., Crous & T.A. Cout.) M.J. Wingf. & Crous and not Teratosphaeria gauchensis (M.-N. Cortinas, Crous & M.J. Wingf.) M.J. Wingf. & Crous, that is commonly documented for the South American region. Conclusions: This study updates the knowledge on forest fungal pathogens in Paraguayan eucalypt plantations and is the first report of T. zuluensis in Paraguay and in South America

New Species of \u3cem\u3eGondwanamyces\u3c/em\u3e From Dying \u3cem\u3eEuphorbia\u3c/em\u3e Trees in South Africa

Gondwanamyces and its Custingophora anamorphs were first described from Protea infructescences in South Africa. Subsequently these unusual fungi were also found on Cecropia in Central America. During an investigation into the decline and death of native Euphorbia trees in South Africa, several fungal isolates resembling the anamorph state of Gondwanamyces were obtained from diseased tissues. In this study these isolates are identified based on morphology and comparisons of DNA sequences. Two previously unknown Gondwanamyces species were identified, both were associated with damage caused by beetles (Cossonus sp.). Inoculation studies showed that the new species of Gondwanamyces are pathogenic on Euphorbia ingens and may contribute to the decline of these trees

Celoporthe dispersa gen. et sp. nov. from native Myrtales in South Africa

In a survey for Cryphonectria and Chrysoporthe species on Myrtales in South Africa, a fungus resembling the stem canker pathogen Chrysoporthe austroafricana was collected from native Syzygium cordatum near Tzaneen (Limpopo Province), Heteropyxis canescens near Lydenburg (Mpumalanga Province) and exotic Tibouchina granulosa in Durban (KwaZulu-Natal Province). The fungus was associated with dying branches and stems on S. cordatum, H. canescens and T. granulosa. However, morphological differences were detected between the unknown fungus from these three hosts and known species of Chrysoporthe. The aim of this study was to characterise the fungus using DNA sequence comparisons and morphological features. Pathogenicity tests were also conducted to assess its virulence on Eucalyptus (ZG 14 clones), H. natalensis and T. granulosa. Plants of H. canescens were not available for inoculation. Results showed distinct morphological differences between the unknown fungus and Chrysoporthe spp. Phylogenetic analysis showed that isolates reside in a clade separate from Chrysoporthe and other related genera. Celoporthe dispersa gen. et sp. nov. is, therefore, described to accommodate this fungus. Pathogenicity tests showed that C. dispersa is not pathogenic to H. natalensis, but that it is a potential pathogen of Eucalyptus and Tibouchina spp

Ceratocystis species, including two new taxa, from Eucalyptus trees in South Africa

The ascomycete genus Ceratocystis (Microascales, Ceratocystidaceae) includes important fungal pathogens of trees, including Eucalyptus species. Ceratocystis species and their Thielaviopsis asexual states are typically associated with insects, such as nitidulid beetles, that spread them over long distances. Eucalyptus trees comprise a substantial component of the forestry industry in South Africa, however, limited information is available regarding Ceratocystis species that infect these trees. In this study, Ceratocystis species were collected from wounds on Eucalyptus trees in all the major plantation regions of South Africa, as well as from insects associated with these wounds. Both morphology and multigene DNA sequence analyses, using three nuclear loci, were used to identify the Ceratocystis species. Of the 260 isolates collected, nine Ceratocystis species, of which two were represented only by their Thielaviopsis anamorph states were identified. These species were C. eucalypticola, C. pirilliformis, C. savannae, C. oblonga, C. moniliformis, T. basicola, T. thielavioides and two Ceratocystis species that are described here as C. salinaria sp. nov. and C. decipiens sp. nov. Insects associated with these Ceratocystis species were Brachypeplus depressus (Nitidulidae), Carpophylus bisignatus, C. dimidiatus (Nitidulidae), Xyleborus affinis (Scolytidae), Litargus sp. (Mycetophagidae) and a Staphylinid (Staphylinidae) species.National Research Foundation of South Africa (NRF), the THRIP Initiative of the Department of Trade and Industry (THRIP/DST), members of the Tree Protection Cooperative Programme (TPCP) and the University of Pretoria.http://link.springer.com/journal/13313hb201

A review of factors associated with decline and death of mangroves, with particular reference to fungal pathogens

Mangrove species growin bays and estuaries in tropical and subtropical latitudes.Mangrove systems are categorized as highly productive, providing crucial environmental functions. Their stability and survival are, however, constantly threatened by anthropogenic activities and there has been an increase in reports of decline and death of these trees globally. Currently, little is known regarding diseases affecting mangroves, particularly those caused by micro-organisms such as fungi. In recent years several studies of the fungi associated with these trees have been conducted and a number of fungal diseases have been identified. However, few studies have been done in South Africa and little is known regarding the health status of mangroves in the country. This review aims to provide a background for further studies of pathogens affecting true mangroves in South Africa. Furthermore, it aims to contribute toward the development of management plans to ensure mangrove health in the country.Department of Science and Technology (DST) and the National Research Foundation (NRF) Center of Excellence in TreeHealth Biotechnology (CTHB) (UID: 40945).http://www.elsevier.com/locate/sajb2017-03-31hb2016Forestry and Agricultural Biotechnology Institute (FABI)Microbiology and Plant Patholog

First report of Teratosphaeria zuluensis causing stem canker of Eucalyptus grandis in Uganda

Teratosphaeria stem canker is one of the most important diseases to have emerged on nonnative plantation-grown Eucalyptus trees globally. In 2012, Eucalyptus grandis trees with typical Teratosphaeria stem canker symptoms were observed in Uganda. Multi-gene sequence analyses of isolates made from these cankers led to the identification of two species of Teratosphaeria on these trees. These were T. gauchensis, previously recorded in Uganda and T. zuluensis. This study represents the first report of T. zuluensis in Uganda. Furthermore, this is the first report of the co-occurrence of T. zuluensis and T. gauchensis in a single area.National Research Foundation (NRF), members of the Tree Protection Cooperative Programme (TPCP) and the THRIP Initiative of the Department of Trade and Industry, South Africa.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1439-0329hb201

Diseases on Eucalyptus species in Zimbabwean plantations and woodlots

Zimbabwe embarked on planting Eucalyptus species in the early 1900’s. Based on a robust breeding programme, it has become a major source of seed for other countries in and outside Africa. Tree health surveys conducted on Eucalyptus in some east and southern Africa countries over the past two decades have revealed several important fungal diseases that were previously not known in the region, but little is known regarding these problems in Zimbabwe. The aim of this study was to identify important eucalypt diseases across Zimbabwe’s agro-climatic regions. Morphological characteristics and DNA sequence data were used to identify pathogens collected to species level. Widespread stem canker diseases, caused by species belonging to the Botryosphaeriaceae and Teratosphaeriaceae, and leaf spot diseases caused by fungi in the Capnodiales, were identified. Armillaria root and stem rot was restricted to a single site in the Eastern Highlands. Fungi that could cause canker or blue stain of timber were isolated from recently harvested stumps and included species of Ceratocystis and Ophiostoma. This study is the first to identify Eucalyptus pathogens to species level in Zimbabwe and we report for the first time the presence of the stem canker pathogen T.gauchensis in southern Africa. The results will provide a foundation for the formulation of future disease management strategies in the country.National Research Foundation (NRF), members of the Tree Protection Cooperative Programme (TPCP) and the THRIP Initiative of the Department of Trade and Industry, South Africa.http://www.tandfonline.com/loi/tsed202016-06-30hb201

Population structure of Chrysoporthe austroafricana in southern Africa determined using Vegetative Compatibility Groups (VCGs)

Chrysoporthe austroafricana is one of the most damaging pathogens of Eucalyptus trees in southern Africa. It also occurs on non-native Tibouchina granulosa trees and native Syzygium species. Additional isolates of the pathogen from previously unstudied countries in the region have become available from survey studies. The aim of this study was to use VCGs to consider the diversity in populations of isolates collected in various countries in southern Africa (Malawi, Mozambique, Namibia, South Africa and Zambia) and from different hosts. We also wanted to determine whether there are shared VCGs among these countries and hosts in southern Africa and establish a VCG tester strain data base. Results showed a high diversity amongst isolates from different countries and hosts, but suggested little movement of VCGs among countries or hosts based on the available isolates. A total of 108 VCG tester strains were identified for southern Africa.The University of Pretoria (UP), National Research Foundation (NRF), Forestry and Agricultural Biotechnology Institute (FABI) and Tree Protection Cooperative Program (TPCP).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1439-0329hb2016Microbiology and Plant Patholog

A serious canker disease caused by Immersiporthe knoxdaviesiana gen. et sp. nov. (Cryphonectriaceae) on native Rapanea melanophloeos in South Africa

Recent disease surveys in the Western Cape province of South Africa have revealed a previously unknown and serious stem canker disease on native Rapanea melanophloeos (Myrsinaceae, Ericales) trees. Cankers commonly result in the death of branches or entire stems. Fruiting structures typical of fungi in the Cryphonectriaceae were observed on the surfaces of cankers. In this study, the fungus was identified and its pathogenicity to R. melanophloeos was tested. Multigene phylogenetic analyses based on DNA sequences of the partial LSU gene, ITS region of the nuclear ribosomal DNA gene and two regions of the β-tubulin (BT) gene, showed that the fungus represents a formerly undescribed genus and species in the Cryphonectriaceae. The fungus was also morphologically distinct from other genera in this family. Inoculation trials showed that the fungus described here as Immersiporthe knoxdaviesiana gen. et sp. nov. is an aggressive pathogen of R. melanophloeos trees.DST/NRF Centre of Excellence in Tree Health Biotechnology (CHTB)http://www.wiley.com/bw/journal.asp?ref=0032-0862hb201

Species delineation in the tree pathogen genus Celoporthe (Cryphonectriaceae) in southern Africa

The genus Celoporthe was first described when C. dispersa was discovered in South Africa associated with dieback and cankers on trees in the Myrtales. Four additional species were recently described from Eucalyptus and Syzygium cumini in China as well as S. aromaticum and Eucalyptus in Indonesia. Inoculation trials have shown that all Celoporthe species, including those that have not been found on Eucalyptus species in nature, are pathogenic to Eucalyptus and they are thus potentially threatening to commercial Eucalyptus forestry. New isolates, morphologically similar to Celoporthe, have been collected from S. legatti in South Africa and S. guineense in Zambia. Multigene phylogenetic analyses based on DNA sequences of the ITS region, TEF1a gene and two areas of the b-tubulin gene revealed additional cryptic species in Celoporthe. Phylogenetic data were supported by morphological differences. These resulted in the description of two previously unknown species of Celoporthe, namely C. fontana and C. woodiana, for two of these cryptic groups, while the third group represented C. dispersa. These species all can readily infect Eucalyptus as well as several species of Syzygium, the latter of which are native to Africa.We thank the University of Pretoria (UP), National Research Foundation (NRF), Forestry and Agricultural Biotechnology Institute (FABI) and Tree Protection Cooperative Program (TPCP) for financial support.http://www.mycologia.org/am201