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1.
《Southern Forests》2013,75(3-4):165-173
Various species of Euphorbia occur in South Africa, including herbaceous, succulent and woody types. The largest of the succulent Euphorbia spp. in South Africa is Euphorbia ingens. These trees have been dying at an alarming rate in the Limpopo province during the course of the last 15 years. Investigations into the possible causes of the death have included the possible role of fungal pathogens. Amongst the fungi isolated from diseased trees were species in the Botryosphaeriaceae. The aim of this study was to identify these fungi using morphology and DNA sequence data of two gene regions (TEF 1-α and ITS). Results showed that Lasiodiplodia theobromae and L. mahajangana were present, representing the first report of Lasiodiplodia species on a succulent Euphorbia species. Pathogenicity studies showed that these Lasiodiplodia species can cause infections on healthy E. ingens trees, implicating them as contributors to the decline of E. ingens. 相似文献
2.
Ophiostomatoid fungi are carried by various bark beetles. However, very little is known about the role of these fungi in conifer roots. We studied ophiostomatoid fungi in roots of dying and dead Pinus sylvestris trees and tested the potential phytotoxicity of some isolates using a sensitive bioassay with Lepidium sativum in Poland. Fungi were identified based on their morphology and DNA sequencing. Three ophiostomatoid fungi, Leptographium procerum, Sporothrix inflata and Ophiostoma pallidulum, were isolated from the roots. The most abundant soil‐borne fungus, S. inflata, and relatively rare O. pallidulum were isolated for the first time from roots of dying and dead pine trees. The frequency of S. inflata and O. pallidulum correlated with tree decline. The fungi were isolated more frequently from roots of dead than dying trees. Sporothrix inflata and O. pallidulum slightly reduced the stem and root growth of L. sativum. Leptographium procerum reduced more significantly root than stem growth. This species reduced root elongation 32–54% after 10–17 days of incubation. 相似文献
3.
《Scandinavian Journal of Forest Research》2012,27(6):497-506
The pine shoot beetle, Tomicus piniperda, is a secondary colonizer of pines and other conifers. Although it is necessary to understand interactions of this insect with other organisms, few studies have focused on its fungal associates. This study focused on the effect of geographical distance on the occurrence of fungi carried by the beetle. Adult beetles were collected from Scots pine (Pinus sylvestris) in North (Rovaniemi) and South (Hyytiälä) Finland. The mycota was isolated and identified using a combination of morphological and molecular data. The results revealed a great diversity of fungal taxa isolated from T. piniperda, with a total of 3073 isolates representing 20 taxonomic units. The most frequently isolated fungi in the bark beetles from North Finland were Beauveria bassiana, Kuraishia sp., whereas Penicillium velutinum was mostly observed in the insects from South Finland. Ophiostoma canum and Ophiostoma minus were also isolated from the beetles from both North and South Finland. The number of fungi isolates per insect was 2.58 in the North and 3.74 in the South, respectively. Significant differences were found between South and North Finland in fungal taxa isolated from the beetles. The highest richness and diversity of the fungal taxa was observed in the South. However, the overall fungal diversity index analysis revealed that the mycobiota was under-sampled which suggests that a proportion of the fungal species may have remained undetected. 相似文献
4.
Kylle Roy Kelly A. Jaenecke Ellen J. Dunkle Dan Mikros Robert W. Peck 《Forest Pathology》2023,53(3):e12812
The ecologically and culturally vital tree species, ʻōhiʻa lehua (Metrosideros polymorpha), is threatened by the fungal pathogens Ceratocystis lukuohia and Ceratocystis huliohia, the causal agents of the disease complex called Rapid ʻŌhiʻa Death (ROD). Four invasive ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) species in the Xyleborini tribe colonize ROD Ceratocystis-infested ‘ōhiʻa and produce inoculum through their frass; however, the potential for direct transmission of the ROD fungi by these beetles was unknown. We fulfilled Leach's rules to support insect transmission of ROD by documenting the visitation of these ambrosia beetles to healthy ‘ōhiʻa trees, culturing C. lukuohia and C. huliohia from the ROD-associated beetles using three different collection methods at multiple study sites, and challenging healthy ʻōhiʻa seedlings with beetles that were exposed to both C. lukuohia and C. huliohia cultures. We documented all four invasive ROD-associated ambrosia beetle species including Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, and Xyleborus perforans to regularly visit healthy ʻōhiʻa trees on sticky traps. Viable Ceratocystis propagules were isolated from all species, and C. lukuohia was most commonly isolated of the two ROD-causing fungi. Consistently across all collection techniques, ROD Ceratocystis spp. were detected on just under 3% of all assayed beetles, with the highest detection rate from X. affinis. All four beetle species were capable of directly transmitting both pathogens to healthy ʻōhiʻa seedlings with a high rate of transfer. Ceratocystis spp. are highly virulent pathogens in trees, and a single inoculation can result in tree death, therefore any direct transmission is a cause for concern. After meeting the criteria of Leach's rules, we propose that Xi. saxesenii, X. affinis, X. ferrugineus, and X. perforans are vectors of C. lukuohia and C. huliohia, particularly in areas of high ROD pressure and tree stress. 相似文献
5.
Die‐back of Schizolobium parahyba var. amazonicum is a serious problem in plantations of these trees in Ecuador. Similar symptoms have also been observed on trees of this species in various parts of South Africa. The most common fungi isolated from disease symptoms on S. parahyba var. amazonicum in both locations were species of the Botryosphaeriaceae. The aim of this study was to identify these fungi from both Ecuador and South Africa, and to test their pathogenicity in greenhouse and field trials. Isolates obtained were grouped based on culture morphology and identified using comparisons of DNA sequence data for the internal transcribed spacer (ITS) and translation elongation factor 1α (TEF‐1α) gene regions. The β‐tubulin‐2 (BT2) locus was also sequenced for some isolates where identification was difficult. Three greenhouse trials were conducted in South Africa along with a field trial in Ecuador. Neofusicoccum parvum was obtained from trees in both areas and was the dominant taxon in South Africa. Lasiodiplodia theobromae was the dominant taxon in Ecuador, probably due to the subtropical climate in the area. Isolates of Neofusicoccum vitifusiforme (from South Africa only), Neofusicoccum umdonicola and Lasiodiplodia pseudotheobromae (from Ecuador only) were also obtained. All isolates used in the pathogenicity trials produced lesions on inoculated plants, suggesting that the Botryosphaeriaceae contribute to the die‐back of S. parahyba trees. While the disease is clearly not caused by a single species of the Botryosphaeriaceae in either region, N. parvum has been introduced into at least one of the regions. This species has a broad host range and could have been introduced on other hosts. 相似文献
6.
Pine plantations in Argentinian Patagonia cover ca. 95,000 ha in Chubut, Río Negro and Neuquén provinces. Exotic bark beetles (Orthotomicus laricis, Hylastes ater and Hylurgus ligniperda) commonly occur in freshly cut logs, stumps and slash. These beetles are vectors of “ophiostomatoid” fungi which include primary tree pathogens as well as important agents of blue stain. The aim of this study was to identify these beetle‐associated fungi. Sawing mills and pine plantations were surveyed three consecutive years. Fungal isolates from stained logs, processed wood and insect galleries were identified based on morphological and DNA sequence comparisons of ITS and β‐tubulin gene regions. Two Grosmannia, one Graphilbum and three Ophiostoma species were identified. Ophiostoma piliferum and O. peregrinum sp. nov. were the most frequently isolated taxa. O. peregrinum occurred in all provinces, colonizing different conifer species and, interestingly, also the native broadleaved species Nothofagus dombeyi. Pine plantation forestry in southern South America includes Argentina, Brazil, Chile, Paraguay and Uruguay. Emerging data from Argentina, Chile and Uruguay revealed some coincidences between these countries, but also several differences, probably, as a result of multiple introduction events. 相似文献
7.
R. N. Heath J. Roux B. Slippers A. Drenth S. R. Pennycook B. D. Wingfield M. J. Wingfield 《Forest Pathology》2011,41(1):48-51
Species in the Botryosphaeriaceae are important canker pathogens of woody plants, including Eucalyptus spp. The recent discovery of the Eucalyptus pathogen, Chrysoporthe austroafricana, on ornamental Tibouchina trees raised the question as to whether Tibouchina spp. might be alternative hosts for other Eucalyptus pathogens. Therefore, the aim of this study was to consider whether species of the Botryosphaeriaceae occurring on Eucalyptus spp. might also occur on ornamental Tibouchina spp. Isolations were made from Tibouchina trees in South Africa, New Zealand and Australia. Isolates were identified using morphological characteristics and DNA‐based techniques. Neofusicoccum parvum and N. mangiferae were identified from the samples. Pathogenicity trials on T. urvilleana showed that both species are pathogenic to this host. 相似文献
8.
J. Roux R. N. Heath L. Labuschagne G. K. Nkuekam M. J. Wingfield 《Forest Pathology》2007,37(5):292-302
Ceratocystis albifundus causes the disease known as wattle wilt of non‐native Acacia mearnsii trees in South Africa, Uganda and Kenya. Infection results in rapid wilt and death of susceptible trees and stem cankers on more tolerant trees. It has been suggested that C. albifundus is indigenous to southern Africa, possibly having spread from native Protea spp. to non‐native A. mearnsii and A. decurrens trees. Although C. albifundus has been collected from Protea spp., these reports are based on limited records for which only aged herbarium specimens exist. During surveys of wound‐infecting fungi on native tree species in South Africa, a fungus resembling C. albifundus was collected from Protea gaguedi, Acacia caffra, Burkea africana, Combretum molle, C. zeyheri, Faurea saligna, Ochna pulchra, Ozoroa paniculosa and Terminalia sericea. The identity of the fungus was confirmed as C. albifundus, using comparisons of DNA sequence data for the ITS and 5.8S gene of the rRNA operon. In pathogenicity trials, lesions were produced on C. molle and A. caffra, with some trees beginning to die at the termination of the experiment. This study represents the first report of C. albifundus from native tree species in South Africa and provides unequivocal evidence that the fungus occurs naturally on native Protea spp. The wide host range of C. albifundus, as well as its abundance on these indigenous hosts lends further support to the view that it is a native African pathogen. 相似文献
9.
《Southern Forests》2013,75(3-4):121-132
Pterocarpus angolensis (kiaat) is a well-known southern African tree species of commercial importance that occurs in several vegetation types in the Zambezian regional centre of endemism. The most prominent of these vegetation types are the Zambezian miombo woodland and undifferentiated woodland. A diverse range of ecosystems within these vegetation types necessitate adaptation by tree species to survive extremes of drought, temperature, altitude, soil nutrition and tolerate fire in order to compete with other plant species. There are several reports of a die-back disease of P. angolensis in Zambia, Zimbabwe and South Africa, but very little is known regarding the cause or significance of this problem. In this review, we provide details regarding the history of the disease and consider its possible causal agents. A pathology study conducted at three locations in South Africa on diseased and dying trees resulted in the collection of 199 fungal isolates; comprising saprophytic species such as Candida, Penicillium and Humicola, and potentially pathogenic species such as Lasiodiplodia theobromae, Cytospora spp. and Fusarium spp. Drought, during several years preceding disease, along with a lack of fire management may have contributed to both the present and past reports of tree die-back and death. Finally, an analysis is made of the importance of the problem and actions that might be taken to alleviate it. 相似文献
10.
In Cameroon, native Terminalia spp. represent an important component of the forestry industry, but limited information is available regarding the fungal pathogens that affect them. The Botryosphaeriaceae are endophytic fungi and latent pathogens that can result in wood stain, cankers, die‐back and death of trees, particularly when trees are under stress. The aim of this study was, therefore, to identify and characterize the Botryosphaeriaceae occurring as endophytes of Terminalia spp. in Cameroon, as part of a larger project to identify potential pathogens of these trees in the country. Samples were collected from three Terminalia spp. in the Central, Southern and Eastern Regions and the resultant Botryosphaeriaceae were identified using morphology and DNA sequence comparisons for the ITS and tef 1‐α gene regions. Furthermore, inoculation trials were conducted to consider the relative pathogenicity of the isolates collected. The majority of isolates (88%) represented species of Lasiodiplodia, including L. pseudotheobromae, L. theobromae and L. parva. The remaining isolates were identified as Endomelanconiopsis endophytica. Pathogenicity trials on young T. mantaly and T. catappa trees revealed that L. pseudotheobromae was the most pathogenic species followed by L. theobromae. 相似文献
11.
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 database. 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. 相似文献
12.
Robert Jankowiak Beata Strzałka Piotr Bilański Magdalena Kacprzyk Karolina Lukášová Riikka Linnakoski Sebastian Matwiejczuk Marcin Misztela Robert Rossa 《European Journal of Forest Research》2017,136(5-6):939-956
Bark beetles (Coleoptera: Curculionidae, Scolytinae) are commonly recognised as important agents of tree mortality in coniferous forests of the Western Carpathians. They, together with weevils, are consistently associated with ophiostomatoid fungi. Information regarding conifer beetle-associated fungi in the Western Carpathians remains incomplete and unreliable, particularly with respect to fir-infesting bark beetles. This study aims to clarify associations between fungi in the genera Graphilbum, Leptographium, Ophiostoma and Sporothrix (Ophiostomatales) and their beetle vectors in Norway spruce (Picea abies), European larch (Larix decidua) and silver fir (Abies alba). Samples associated with 20 bark beetle species and weevils were collected from nine stands in Poland and the Czech Republic. Fungi were isolated from adult beetles and galleries. Isolates were identified based on morphology, DNA sequence comparisons for four gene regions (ITS, LSU, ß-tubulin, TEF 1-α) and phylogenetic analyses. In total, 46 distinct taxa were identified, including 25 known and 21 currently unknown species. Several associations between fungi and subcortical insects were recorded for the first time. In addition, O. borealis and O. quercus were detected from A. alba for the first time. The composition of the fungal communities varied among the studied tree species and to a lesser degree among the beetle species. The spruce-infesting bark beetles were commonly associated with species of Leptographium s. l. and Ophiostoma s. str.; the larch-infesting bark beetles were often associated with Ophiostoma s. str. and Sporothrix, while the fir-infesting bark beetles were commonly associated with Ophiostoma s. str. and Graphilbum. The most commonly encountered fungal associates of the examined insects were (a) Grosmannia cucullata, G. piceiperda, Grosmannia sp. 1, Ophiostoma macroclavatum and O. piceae with the spruce-infesting bark beetles; (b) O. pseudocatenulatum and Sporothrix sp. 1 with the larch-infesting bark beetles; and (c) O. piceae, Ophiostoma sp. 2 and Graphilbum sp. 2 with the fir-infesting bark beetles. The differences in fungal associates among the bark beetle species occurring on P. abies, L. decidua and A. alba could be linked to the different habitats that these beetles occupy. 相似文献
13.
Amani Bellahirech Maria L. Incio Steve Woodward Mohamed L. Ben Jama Filomena Nbrega 《Forest Pathology》2019,49(1)
Ambrosia beetles, including Platypus cylindrus, commonly act as vectors of Ophiostomatales. In an investigation of fungi associated with P. cylindrus, several species of Ophiostomatales were identified, including two species of Ophiostoma s. str. These two species were characterized based on comparisons of DNA sequences of the internal transcribed spacer regions including the 5.8S gene of rDNA and β‐tubulin gene. Two distinct clades were discernable in the phylogenetic trees, supported by high bootstrap values. One clade included the species Ophiostoma tsotsi, reported herein for the first time in Tunisia, and the species Ophiostoma quercus. 相似文献
14.
The association between Tomicus destruens and fungi of the genus Leptographium was studied in Pinus pinea and P. pinaster forests in Tuscany, central Italy. Fungi were isolated from adult beetles and from pine tissues from infested trees. On average, Leptographium spp. were associated with 18% of beetles in breeding galleries, 35% of emergent brood beetles and 18% of beetles undergoing maturation feeding in pine twigs. The fungal species most frequently identified were Leptographium wingfieldii and L. lundbergii while L. guttulatum and L. serpens were also found. 相似文献
15.
Ophiostomatoid fungi are known to be associated with various species of bark beetles. However, information about fungal associates of root‐feeding bark beetles in Europe is still fragmentary. For this reason, the fungal associates of Hylastes ater, H. opacus and Hylurgus ligniperda on Pinus sylvestris were isolated and identified. A total of 743 fungal isolates were collected and separated into 10 morphological groups. Analyses of ITS rDNA and partial β‐tubulin gene sequences confirmed that these groups represented distinct species. The 10 species included a total of 13 associations between fungi and bark beetles that had not been recorded previously. All of the bark beetles examined were frequently associated with ophiostomatoid fungi. The fungal diversity and relative abundance of species were very similar in the three species of root‐feeding bark beetles. The most commonly encountered associates of these beetles were Grosmannia radiaticola, Leptographium lundbergii, L. procerum and L. truncatum. Insect infestation data furthermore suggest that Hylastes spp. and Hg. ligniperda are also important vectors of the fungal pathogen Sphaeropsis sapinea. 相似文献
16.
Characterization of Cylindrocarpon‐like species associated with litter in the old‐growth beech forests of Central Europe 
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下载免费PDF全文 R. Jankowiak H. Stępniewska J. Szwagrzyk P. Bilański G. Gratzer 《Forest Pathology》2016,46(6):582-594
Cylindrocarpon‐like fungi are globally distributed plant pathogens and have a wide range of host species. However, very little is known about the species that live in the topsoil of forests and their potential role in reducing the natural regeneration of tree species, particularly of forest trees that produce abundant fruit only once every few years. To enhance our understanding of the species that inhabit the topsoil, we studied the diversity and pathogenicity of Cylindrocarpon‐like fungi inhabiting the litter in old‐growth mixed‐beech forests in the Carpathians (Poland) and in the Alps (Austria), and in a managed beech stand in the Krakowsko‐Cz?stochowska Highland (Poland). The fungi inhabiting the beech litter were investigated using beechnuts and pine seedlings as bait. Isolates were identified based on morphology and DNA sequencing. The pathogenicity of the most common species was investigated by inoculating beech germinants. A wide range of Cylindrocarpon‐like fungi were associated with the beech litter: 718 cultures representing 12 species were isolated. Five taxa were identified down to species level: namely Ilyonectria crassa, I. pseudodestructans, I. rufa, Neonectria candida and N. obtusispora, and seven species were identified to genus level (Neonectria or Ilyonectria species). Ilyonectria destructans, which is considered to be the sexual morph of ‘Cylindrocarpon destructans’, was not found. There were qualitative and quantitative differences between the different forest sites in terms of Neonectria and Ilyonectria species composition in beech litter. The isolation frequency and species richness of Cylindrocarpon‐like fungi were greatest in beech litter taken from old‐growth mixed‐beech forests. Neonectria and Ilyonectria species were capable of killing beech germinants, suggesting that they may play a negative role in natural beech regeneration. 相似文献
17.
The mountain pine beetle (MPB) vectors three blue‐stain fungi, Grosmannia clavigera, Ophiostoma montium and Leptographium longiclavatum, which contribute to the success of the beetles and the death of the trees. The utility of two methods, heat pulse velocity (HPV) and lesion length, for assessing the relative virulence of these fungi were compared on jack pine in central Alberta. The HPV monitoring apparatus failed to detect xylem sap flow in any of the trees and, thus, could not be used to assess fungal virulence. In contrast, measurement of lesion lengths was more sensitive and provided further evidence that G. clavigera and L. longiclavatum are more virulent than O. montium. The failure of the HPV apparatus to detect sap flow suggests that the study trees were moisture stressed, a factor likely to increase their susceptibility to MPB. Thus, this method is not appropriate for assessing the response of the most susceptible (i.e. drought stressed) trees to MPB and its associated fungi. 相似文献
18.
In the mid-1970s, Mozambique embarked on several forestry projects to promote and establish large plantation areas with eucalypt trees. The planted species included Corymbia citriodora, Eucalyptus camaldulensis, E. saligna and E. tereticornis. Similar to other regions of the world, pests and pathogens pose a significant threat to eucalypt plantations in Mozambique, but little is known regarding the diseases of trees in the country. The aim of this study was to provide the first detailed consideration of the possible disease problems affecting plantation- grown eucalypt species in the central and northern provinces of Mozambique. Isolates of fungal pathogens were obtained from material displaying disease symptoms collected during two field surveys conducted in 2010 and 2011. Representative fungal isolates were identified using DNA sequence data. Stem canker diseases caused by fungi in the Botryosphaeriaceae, Cryphonectriaceae and Teratosphaeriaceae, as well as leaf spots caused by species of Calonectria, Pilidiella, Pilidium and Phakopsora myrtacearum were commonly encountered. Their relative importance to the future of planation forestry in Mozambique is discussed. 相似文献
19.
小蠹虫伴生菌研究概况 总被引：11，自引：0，他引：11
小蠹虫伴生菌是在植物-小蠹虫-伴生菌系统中,削弱树木抗性、协助小蠹虫侵害的重要因子。伴生菌与小蠹虫的联系和相互适应是在长期协同进化中形成的。寄主树木对伴生菌的抗御作用主要是通过物理防御、化学防御进行的。而伴生菌对寄主树的侵害又常常是与小蠹虫协同作用的。因此,揭示伴生菌在小蠹虫相互生态联系,探讨伴生菌在植物-小蠹虫-伴生菌系统中所扮演的角色,对于防治小蠹虫危害、保护寄主树木具有重要意义。 相似文献
20.
Andreja Repe Thomas Kirisits Barbara Piškur Maarten de Groot Bojka Kump Maja Jurc 《Annals of Forest Science》2013,70(7):717-727