Ceratocystis spp. and Botryosphaeriaceae on plantation Acacia species in Central Sumatra, Indonesia

The use of Acacia spp. in plantation forestry increased dramatically in Indonesia since the 1980’s after the Indonesian Government initiated a plantation development program known as Hutan Tanaman Industri (HTI). The aim of this programme is to supply raw material to especially the pulp and paper industries. Currently, more than one million hectares of Acacia plantations have been established, mainly on the islands of Kalimantan and Sumatra. These Acacia plantations, with A. mangium and A. crassicarpa as the main species, display robust growth with mean annual increments (MAI) of 25-30 m3/ha/year and 40-46 m3/ha/year on the average and the best site respectively. However, diseases limit the success of forestry plantations in Indonesia. During disease surveys in Acacia plantations in Indonesia, symptoms resembling those caused by Botryosphaeriaceae and Ceratocystis spp. were identified and representative samples were collected from wounded and diseased A. mangium trees. Studies in this dissertation described the causal agents of the disease and provided some practical solutions to reduce the incidence of the disease. Seven fungal species were discovered, five of them are new to science, one representing a first report for Acacia spp. and one other species is confirmed as the most common fungal species in Acacia plantations in Indonesia. The first chapter of this dissertation provided a background to the forestry industry in Indonesia and details were given on the diseases affecting plantation Acacia spp. in Indonesia. The review clearly shows that diseases such as stem diseases and root diseases can have a severe impact resulting in retarded growth of trees, reduced timber quality, and in severe cases they result in tree death. The most common disease reported from Acacia plantations prior to this dissertation was heart rot and root rot. The second chapter outlines the discovery of Ceratocystis acaciivora prov. nom., a new species, and C. manginecans, a recently described species that causes a serious disease of mango trees in Oman and Pakistan, associated with disease of A. mangium in Indonesia. Identification of these fungi was achieved using morphological characteristics and comparison of DNA sequence data for the ITS, β-tubulin and Elongation Factor 1- gene regions. From pathogenicity trials on A. mangium and A. crassicarpa, both in the greenhouse and the field, it was clear that these fungi are pathogens. In chapter 3 of the dissertation, three previously undescribed Ceratocystis species in the C. monililiformis sensu lato complex are identified. These have been given the names C. inquinans prov. nom., C. sumatrana prov. nom. and C. microbasis prov. nom. and were obtained from wounded A. mangium trees. The virulence of these three new species was tested on A. mangium and A. crassicarpa in the greenhouse and in the field. The results indicate that all three species are mild pathogens but they have the potential to cause disease on A. mangium and A. crassicarpa. The fourth chapter of this dissertation reports on the occurrence of three species in the Botryosphaeriaceae on plantation-grown Acacia spp. in Indonesia. Two of the species are shown to be new to science and were provided with the names Pseudofusicoccum sumatranum prov. nom. and P. acaciicola prov. nom. The third species was identified as the well-known tree pathogen, Lasiodiplodia theobromae. Pathogenicity results indicated that all three species have the potential to cause disease of A. mangium and A. crassicarpa. However, L. theobromae was the most pathogenic and was the most common species isolated. In the fifth chapter, the impact of different wound and inoculum types on infection by C. acaciivora prov. nom. and L. theobromae, the two most pathogenic wound-infecting pathogens on A. mangium and A. crassicarpa, is evaluated. Clear differences were found between careful and rough pruning techniques. The results indicated that improved management practices will minimize disease risk in plantations.Dissertation (MSc)--University of Pretoria, 2008.Microbiology and Plant PathologyMScUnrestricte

Cryptometrion aestuescens gen. sp. nov. (Cryphonectriaceae) pathogenic to Eucalyptus in Indonesia

The recently described Cryphonectriaceae (Diaporthales) includes numerous important tree pathogens such as the chestnut blight pathogen Cryphonectria parasitica, and various species of Chrysoporthe that cause serious stem canker diseases on Eucalyptus. A recent investigation of dying Eucalyptus grandis clonal hedges in northern Sumatra, Indonesia, revealed the presence of an unknown member of the Cryphonectriaceae. DNA sequence comparisons with other members of the Cryphonectriaceae showed that the Indonesian fungus represents a new genus and species in the family, for which we provide the name Cryptometrion austuescens gen. sp. nov. It can be distinguished from other Cryphonectriaceae on Eucalyptus, such as Chrysoporthe, Microthia, Holocryphia and Cryphonectria, based on its orange, limited stromatic tissue, single septate, fusoid to ellipsoid ascospores and the absence of paraphyses among the conidiogenous cells in the anamorph. Inoculations with this fungus on two clones of E. grandis showed that it is highly pathogenic and has the capacity to cause serious losses to Eucalyptus plantations in the region

Pruning quality affects infection of Acacia mangium and A. crassicarpa by Ceratocystis acaciivora and Lasiodiplodia theobromae

Pruning (singling) is a common silvicultural practice in commercial Acacia plantations because these trees tend to have multiple stems. The wounds resulting from pruning are susceptible to infection by pathogens. Ceratocystis acaciivora and Lasiodiplodia theobromae have recently been shown to be important pathogens of A. mangium in Indonesia, where they are commonly associated with wounds on trees. The aim of this study was to determine the impact of different wound types on infection of A. mangium and A. crassicarpa by these two pathogens. Isolates of C. acaciivora and L. theobromae, found to be the most pathogenic in a prior study, were used to inoculate pruning wounds. Results showed that pruning conducted in a manner to reduce stem damage, resulted in lower levels of fungal infection. Where pruning resulted in tearing of the bark, there were greater levels of infection and disease occurred even without artificial inoculation.Inoculation of pruning wounds on A. mangium and A. crassicarpa showed that both fungi have the potential to cause disease. However, C. acaciivora was most pathogenic. Results of this study showed conclusively that careful pruning will result in lower levels of disease in young A. mangium and A. crassicarpa plantations in Indonesia.The Tree Protection Co-operative Programme (TPCP) and the South African National Research Foundation are thanked for financial support to undertake this study. The first author also recognizes the support of PT Riau Andalan Pulp and Paper for support to conduct post graduate studies in South Africa.http://www.nisc.co.za/journals?id=11nf201

A new wilt and die-back disease of Acacia mangium associated with Ceratocystis manginecans and C. acaciivora sp. nov. in Indonesia

Species of Ceratocystis are well-known wound related pathogens of many tree species, including commercially planted Acacia spp. Recently, several Ceratocystis isolates were collected from wilting A. mangium in plantations in Indonesia. The aim of this study was to identify these Ceratocystis isolates and to investigate their ability to cause disease on two plantation-grown Acacia spp. using greenhouse and field inoculation experiments. For identification, morphological characteristics and comparisons of DNA sequence data for the ITS, β-tubulin and TEF 1-α gene regions, was used. Ceratocystis isolates were identified as C. manginecans, a serious pathogen of mango trees in Oman and Pakistan and a previously undescribed species, described here as C. acaciivora sp. nov. Both fungi produced significant lesions in inoculation experiments on A. mangium and A. crassicarpa, however, C. acaciivora was most pathogenic suggesting that this fungus is the primary cause of the death of trees under natural conditions

Comparison of procedures to evaluate the pathogenicity of Ceratocystis fimbriata sensu lato isolates from Eucalyptus in South Africa

Ceratocystis fimbriata sensu lato (s.l.) is an important pathogen of Eucalyptus. Pathogenicity of isolates has typically been evaluated by inoculating seedlings under greenhouse conditions. It is, however, not clear how accurately this reflects pathogenicity under field conditions. In this study, five techniques to potentially screen C. fimbriata isolates for their relative pathogenicity to Eucalyptus were compared. These included: in vitro growth comparisons on artificial media; inoculations on apples; inoculation on Eucalyptus seedlings in a greenhouse; inoculations on Eucalyptus bolts freshly cut from stems of young trees; and field inoculations on young trees. Eight isolates of C. fimbriata s.l. collected from various areas in South Africa were used. There was considerable variation in growth in culture and aggressiveness of the eight isolates. Field inoculations on young trees were best correlated with inoculations of bolts (r = 0.76). Lower correlation coefficients were obtained with seedlings (r = 0.59), apple inoculations (r = 0.56), and in vitro colony growth (r = 0.42). Inoculation of bolts provides a rapid and reliable method to screen isolates of C. fimbriata s.l. for pathogenicity to Eucalyptus.National Research Foundation (NRF), members of the Tree Protection Co-operative Programme (TPCP), THRIP initiative of the Department of Trade and Industry

Calonectria species diversity on eucalypts in Indonesia

Diseases increasingly threaten the rapidly expanding eucalypt plantation industry of Indonesia. Of these, leaf blight caused by Calonectria spp. is considered amongst the more important problems, causing losses both in production nurseries and plantations. Using DNA sequence data based on the translation elongation factor 1-alpha, β-tubulin, calmodulin, and histone H3 gene regions, 163 isolates of Calonectria spp. obtained from diseased eucalypt seedlings in nurseries and infected leaves in plantations were identified as Calonectria acicola, C. hawksworthii, C. lombardiana, C. multiseptata, C. pseudoreteaudii and C. reteaudii. Of these, C. lombardiana was by far the most commonly isolated and accounted for approximately 84% of the isolates. Given the predominance of this fungus, it is interesting that it has not previously been reported from Indonesia. This is also the first report of C. pseudoreteaudii and C. acicola from the country. All six species of Calonectria were found to be pathogenic to eucalypts in artificial inoculation studies. Calonectria lombardiana was generally the most pathogenic species and eucalypt genotypes displayed different levels of susceptibility, providing confidence that disease caused by this fungus can be reduced by selecting disease-tolerant planting stock.Royal Golden Eagle (RGE) and the Forestry Agricultural Biotechnology Institute (FABI) at the University of Pretoria as part of the RGE-FABI Tree Health Programme.https://www.tandfonline.com/loi/tsfs202024-03-15hj2023BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant PathologyPlant Production and Soil Scienc

Screening clonally replicated Acacia mangium breeding populations for tolerance to Ceratocystis canker and wilt disease

Three screening trials of clonally replicated Acacia mangium seedlings were evaluated for survival and lesion length following inoculation with locally collected strains of Ceratocystis in Indonesia. Tolerance in the population was low with 6.7 of the 1033 clones represented by more than 4 ramets surviving repeated inoculations. Differences in tolerance among populations were slight; however, populations with consistently higher survival and shorter lesion lengths were from Papua New Guinea rather than Queensland. Estimates of the proportion of the experimental variation attributable to differences among parents (heritability) were low to moderate for both survival and lesion length. Estimates of the proportion of the experimental variation that was attributable to differences among clones (repeatability) were greater but typically similar to the heritability estimates, indicating that initial improvements from selection will primarily be derived from identifying tolerant parents. While genetic correlations among experiments were positive, estimates could not exclude the existence of host–pathogen interactions. Two validation trials of the tolerant clones were assessed 9 months after establishment; these trials verified that one-third of the clones identified in the nursery screening were also tolerant to Ceratocystis in field trials. The experiments confirmed that nursery screening may be used to quickly focus efforts on parents that produce more tolerant progeny, screening additional seedlings to increase selection intensity rather than using clonal replication to increase accuracy would lead to greater improvements in tolerance and field trials are required to verify disease tolerance at later ages. © 2022, The Author(s)

Three new Ceratocystis spp. in the Ceratocystis moniliformis complex from wounds on Acacia mangium and A. crassicarpa

The genus Ceratocystis includes many important tree pathogens and agents of sap stain. These fungi have a global distribution and commonly infect wounds on trees. During a survey of wound-infecting pathogens in the genus Ceratocystis on plantation-grown Acacia mangium trees in Indonesia, several isolates resembling Ceratocystis moniliformis sensu lato (s.l.) were obtained. The aim of this study was to identify these isolates and to test their pathogenicity on commercially grown Acacia spp. in the country. Use was made of morphology and comparisons of DNA sequence data for the ITS, β-tubulin, and transcription elongation factor 1-α gene regions to identify the isolates. Three previously undescribed species in the C. moniliformis s.l. species complex were identified and are described here as C. inquinans sp. nov., C. sumatrana sp. nov., and C. microbasis sp. nov. Pathogenicity trials on Acacia mangium and A. crassicarpa in the greenhouse and in the field indicated that all three species have the potential to infect A. mangium and A. crassicarpa, although they are not considered important pathogens.National Research Foundation (NRF), members of the Tree Protection Co-operative Programme (TPCP), THRIP initiative of the Department of Trade and Industry; Department of Science and Technology (DST)/NRF Centre of Excellence in Tree Health Biotechnology (CTHB