scholarly journals Fungi isolated from shoots showing ash dieback in the Wolica Nature Reserve in Poland and artificially inoculated seedlings with Hymenoscyphus fraxineus

2019 ◽  
Vol 61 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Anna Żółciak ◽  
Justyna Anna Nowakowska ◽  
Artur Pacia ◽  
Nenad Keča ◽  
Tomasz Oszako
Keyword(s):  
Nature Reserve ◽  
Pathogenic Fungus ◽  
Internal Transcribed Spacer Region ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
Serious Disease ◽  
One Year ◽  
In The Beginning ◽  
Qualitative Changes

Abstract Ash dieback caused by an alien, invasive fungus Hymenoscyphus fraxineus is a serious disease of European ash species in many parts in Europe. In Poland, the disease was recorded in the beginning of the 1990s. This study was performed in 2016–2017 with the aim to identify fungi isolated from ash shoots showing dieback symptoms in the Wolica Nature Reserve in Poland, as well as from shoots of two years-old ash seedlings inoculated with H. fraxineus in the greenhouse. The most frequently isolated fungi from shoots of common ash (associated with the pathogenic fungus H. fraxineus) were identified on the basis of sequencing of the internal transcribed spacer region (ITS1) of fungal rDNA. In total, 19 fungal taxa were identified for ash shoots as follows: H. fraxineus, Fusarium avenaceum, Alternaria spp., Phomopsis oblonga, Diplodia mutila and other Phomopsis spp. The pathogen H. fraxineus was not found for all the shoots samples; one year after inoculation the aforementioned fungi and other species as: Alternaria alternata, Bionectria ochroleuca, Epicoccum nigrum, F. acuminatum, F. avenaceum, and Paraphaesphaeria neglecta were identified in inoculation point, as well as H. fraxineus. The same quantitative and qualitative changes of organisms were observed in the case of artificially colonised ash seedlings in the greenhouse, as well as in the shoots of adult ash trees in the forest.

scholarly journals Situation and perspectives of European ash (Fraxinus spp.) in Ukraine: focus on eastern border

2019 ◽  
Vol 25 (2) ◽  
pp. 193-202
Author(s):  
Kateryna V Davydenko ◽  
Valentyna Borysova ◽  
Olena Shcherbak ◽  
Yevhen Kryshtop ◽  
Valentyna Meshkova
Keyword(s):  
Pathogenic Fungus ◽  
Total Mortality ◽  
Fraxinus Excelsior ◽  
Bacterial Disease ◽  
Eastern Region ◽  
Ash Dieback ◽  
Epicormic Shoots ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
European Ash

The health condition of European ash (Fraxinus excelsior) stands in Ukraine has become worse since 2006. Firstly, in 2011 an alien invasive pathogenic fungus Hymenoscyphus fraxineus was identified in the eastern part of the country and, subsequently, its presence was confirmed in the western and central parts. The aims of our research were to evaluate the health of ash trees and identify the main causes of ash decline in different regions of Ukraine with emphasis on ash dieback and its association with collar rots.    Results showed that since 2013 the number of trees with ash dieback symptoms has been gradually increasing, reaching up to 92 % in 2018. Total mortality due to ash dieback was up to 9 % in 2018. Disease intensity remains high in northern and central Ukraine comparing with the east. Branch dieback, collar rots, epicormic shoots and bacterial disease of ash occurred more often in the eastern region, some symptoms were observed simultaneously. Ash bark beetle galleries, as well as foliage browsing insects, were found mostly in weakened and/or dying trees.    It was indicated that collar rots significantly increase the mortality of ash trees. Armillaria spp. fungi were found to be frequently associated with ash dieback on living stems and fallen trees in 2017, causing high rates of mortality in the northern and central regions. For further ash conservation and breeding programmes, resistant trees in severely damaged regions should be selected to preserve genetic diversity in ash populations.                                                       Keywords: Fraxinus excelsior, ash dieback, collar rot, bacterial disease, epicormic shoots, Hymenoscyphus fraxineus, Armillaria spp.

scholarly journals Host Range of Hymenoscyphus fraxineus in Slovak Arboreta

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 596
Author(s):  
Katarína Pastirčáková ◽  
Katarína Adamčíková ◽  
Marek Barta ◽  
Jozef Pažitný ◽  
Peter Hoťka ◽  
...  
Keyword(s):  
Host Range ◽  
Native Species ◽  
Pathogenic Fungus ◽  
Nuclear Ribosomal Dna ◽  
New Host ◽  
Ash Dieback ◽  
Susceptible Host ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
Pcr Targeting

The health of 34 different Fraxinus taxa in association with the pathogenic fungus Hymenoscyphus fraxineus was assessed in four Slovak arboreta. Averaged across all arboreta, nearly one-quarter (24.9%) of all evaluated trees showed ash dieback symptoms. The damage was most serious on the common ash F. excelsior, a native species. The percentage of dead trees did not exceed 2% for all evaluated trees. Generally, ash trees of all ages were affected, though the intensity of the damage varied among the sites. The identity of H. fraxineus was confirmed by conventional PCR targeting the internal transcribed spacer (ITS) sequences of the nuclear ribosomal DNA, as well as the 18S gene/ITS-2 region of the rDNA operon. In Slovakia, the pathogen has expanded its host range from native species not only to their ornamental cultivars, but also to introduced North American (F. cinerea, F. latifolia, F. pennsylvanica, F. quadrangulata) and Asian (F. bungeana, F. chinensis ssp. rhynchophylla, F. mandshurica) ash species. H. fraxineus was also observed on the previous year’s leaf petioles of the native European species F. ornus, considered a weakly susceptible host. In Slovak arboreta, H. fraxineus was found on 23 Fraxinus taxa; 21 of them represent first records for the country. F. bungeana is recorded as a new host species of H. fraxineus.

scholarly journals Lessons from the Frontline: Exploring How Stakeholders May Respond to Emerald Ash Borer Management in Europe

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 617 ◽  
Author(s):  
Mariella Marzano ◽  
Clare Hall ◽  
Norman Dandy ◽  
Cherie LeBlanc Fisher ◽  
Andrea Diss-Torrance ◽  
...  
Keyword(s):  
Biological Control ◽  
Social Acceptance ◽  
Emerald Ash Borer ◽  
Social Acceptability ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
The Social ◽  
Ash Trees ◽  
The Usa ◽  
Management Approaches

The emerald ash borer (EAB) has caused extensive damage and high mortality to native ash trees (Fraxinus; sp.) in North America. As European countries battle with the deadly pathogen Hymenoscyphus fraxineus (ash dieback) affecting European ash (Fraxinus excelsior), there is concern that the arrival of EAB will signal the demise of this much-loved tree. While Europe prepares for EAB it is vital that we understand the social dimensions that will likely influence the social acceptability of potential management measures, and experiences from the USA can potentially guide this. We draw on differing sources including a literature review, documentary analysis, and consultation with key informants from Chicago and the Twin Cities of Minneapolis and St. Paul. In this paper, we focus on EAB management responses that involve chemical applications, tree felling and replanting, and biological control, and assess their likely social acceptability to stakeholders based on the perceived risks and benefits. Benefits involve protecting specific ash trees and slowing the spread of EAB across the landscape. Risks include collateral harm from insecticide use on human and environmental health, financial costs and liabilities, and the effectiveness of each approach. Biological control and replacing ash with other species are likely to be largely acceptable across contexts and stakeholder groups but pre-emptive felling and insecticide application could be more problematic if seeking widespread social acceptance. Based on our observations from the evidence collected we offer suggestions for approaching EAB management in Europe with a focus on improving prospects of social acceptability. Strong engagement will be necessary to establish the relevance and reason for using different management approaches and to build awareness and trust.

First report of Diplodia fraxini and Diplodia subglobosa causing canker and dieback of Fraxinus excelsior in Slovenia

Plant Disease ◽  
2021 ◽  
Author(s):  
Benedetto T. Linaldeddu ◽  
Carlo Bregant ◽  
Lucio Montecchio ◽  
Ana Brglez ◽  
Barbara Piškur ◽  
...  
Keyword(s):  
Sequence Data ◽  
Fungal Species ◽  
Pathogenicity Test ◽  
Limited Information ◽  
Internal Transcribed Spacer Region ◽  
Ash Dieback ◽  
Fungal Isolation ◽  
Hymenoscyphus Fraxineus ◽  
Botryosphaeriaceae Species ◽  
European Ash

Over the last decades the vitality and productivity of European ash trees in Slovenia has been seriously impacted by the onset of canker and dieback disease symptoms on young and old trees, primarily identified as ash dieback caused by Hymenoscyphus fraxineus. Given the limited information available about the aetiology of this emerging disease, a study was carried out to isolate, identify and characterize the fungal species involved in the observed ash symptoms. Field surveys were conducted in five forest sites where 50 symptomatic branch samples were collected. All samples were inspected and used for fungal isolation. Based on morphology, colony appearance and DNA sequence data of the internal transcribed spacer region (ITS), 125 fungal colonies belonging to five species were isolated and identified. Only a few symptomatic ash samples yielded colonies of H. fraxineus, whereas Botryosphaeriaceae species were isolated with a high frequency, with Diplodia fraxini as the dominant species. A pathogenicity test proved that all isolated species were pathogenic on European ash, causing bark lesions and wood discoloration. All Botryosphaeriaceae species isolated in this study are reported for the first time on European ash in Slovenia.

scholarly journals Dealing with dieback: forest manager attitudes towards developing resistant ash trees in the United Kingdom

2019 ◽  
Vol 92 (5) ◽  
pp. 554-567 ◽  
Author(s):  
Mariella Marzano ◽  
Paul Woodcock ◽  
Christopher P Quine
Keyword(s):  
Native Species ◽  
Ash Dieback ◽  
The United Kingdom ◽  
Hymenoscyphus Fraxineus ◽  
Resistant Varieties ◽  
Ash Trees ◽  
New Varieties ◽  
Time Required ◽  
The Uk ◽  
Past Experiences

Abstract European ash (Fraxinus excelsior L.) is a highly valued native species in the UK and elsewhere. The rapid spread and predicted impact of ash dieback (caused by Hymenoscyphus fraxineus), has led researchers to explore a range of responses from introducing non-native ash to use of Genetic Modification (GM) technologies to develop disease resistance. To support decisions over which approaches should receive further investment to encourage adoption, it is necessary to understand what is acceptable to forest practitioners. Interviews with 22 forest advisors and managers revealed ash is highly valued for the multiple benefits it provides but past experiences with pest and diseases have encouraged a more cautious (‘wait and see’) attitude to approaches for dealing with ash dieback. These practitioners showed a strong interest in the concept of resistant ash but emphasized that any ‘new’ varieties should have similar characteristics, retain genetic diversity and be able to withstand future pests. There was limited support for planting non-native ash and use of GM methods and greater support for traditional breeding, though views varied dependent upon objectives and could evolve with experience countering the disease. There were concerns about the time required to produce resistant varieties and more information was needed about the costs, benefits and impacts of the different approaches. These findings point to the need for continued communication and engagement with stakeholders in the refinement of responses to dieback and any development of resistant ash.

scholarly journals The impact of ash dieback on veteran trees in southwestern Sweden

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Vikki Bengtsson ◽  
Anna Stenström ◽  
C. Philip Wheater ◽  
Karin Sandberg
Keyword(s):  
Key Words ◽  
Mortality Rates ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
Veteran Trees ◽  
Significant Difference ◽  
Ash Trees ◽  
Dieback Disease ◽  
The Impact ◽  
First Time

Ash dieback (Hymenoscyphus fraxineus) is a fungal disease which affects ash throughout Sweden.  Monitoring to study of the impact of ash dieback on veteran trees was undertaken in southwest Sweden in 2009, 2011, 2013, 2015, and 2020. The study found that 94.5% of the ash trees observed were affected by ash dieback disease in 2020 compared with 62% in 2009.  70 of the studied ash trees have died (21%) since the monitoring began. In 2009 there was no relationship between girth and ash dieback, but in 2020 the correlation between girth and the impact of ash dieback was statistically significant. In 2020, also for the first time during monitoring, the ash trees in the shade were significantly more affected by ash dieback, compared with trees standing in the open. This difference was not detected in 2013 or 2015. The effect of ash dieback on pollarded trees has varied between the years studied, but in 2020 there is no longer any significant difference between the pollarded and the non-pollarded ash trees.  There was however a significant difference in the mortality rates between the groups of trees, with ash trees pollarded in more recent times having the highest mortality. Therefore, the recommendation in relation to veteran trees with ash dieback is that all pruning on veteran ash trees should be avoided. Pollarding should only be done on ash pollards that are in a regular cutting cycle and are not showing any symptoms of ash dieback.  If possible, clear around old ash trees if they are in shaded conditions. Given that there are relatively few studies on the impact of ash dieback on veteran ash trees, the results of this study should also be relevant outside of Sweden and for the management of ash trees in non-woodland situations. Key words: Ash dieback, pollards, veteran trees, Hymenoscyphus fraxineus, ash

scholarly journals Decline of Fraxinus excelsior L. in parks of Saint Petersburg: Who is to blame – Hymenoscyphus fraxineus or Diplodia spp.?

2020 ◽  
Vol 73 (1) ◽  
pp. 43-51
Author(s):  
Dmitrii A. Shabunin ◽  
Andrey V. Selikhovkin ◽  
Elena Yu. Varentsova ◽  
Dmitry L. Musolin
Keyword(s):  
Light Microscopy ◽  
Fraxinus Excelsior ◽  
Ash Dieback ◽  
Saint Petersburg ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
Fallen Leaves ◽  
European Ash

Abstract The weakening and decline of European ash Fraxinus excelsior L. and other ash species have been recorded at different locations in the suburbs of Saint Petersburg, Russia. During the summer of 2019 and spring of 2020, samples from leaves, petioles, and shoots were collected from the weakened and declining ash trees in three parks in Pushkin and Gatchina and maintained in humid chambers to induce the fructification of fungi. In total, 30 taxa of micromycetes belonging to 23 genera were identified using methods of light microscopy. Hymenoscyphus fraxineus, a putative agent of ash dieback, was not recorded in the samples collected in the crowns of trees, but only on the petioles of the fallen leaves in spring. Out of all the micromycetes recorded, only coelomycetes from the genus Diplodia Fr. (in particular, D. mutila) can damage the branches of ash trees and, thus, be considered pathogenic. It is likely that H. fraxineus opens “the entry of infection” and Diplodia spp. cause the major weakening and decline of branches. The data obtained can significantly change our understanding of the causes of ash dieback and possible methods of ash stand preservation. The reason for the low pathogenicity and activity of H. fraxineus, as well as the possible role of ascomycetes Diplodia spp. in the dieback of ash stands requires further research.

scholarly journals Dying of ash (Fraxinus excelsior L.) in the ‘Jesionowe Góry’ Nature Reserve

2016 ◽  
Vol 77 (2) ◽  
pp. 124-133 ◽  
Author(s):  
Michał Orzechowski ◽  
Jakub Kacprzak ◽  
Wojciech Kędziora
Keyword(s):  
Natural Regeneration ◽  
Nature Reserve ◽  
Growing Season ◽  
Health Condition ◽  
Site Conditions ◽  
Age Classes ◽  
Ash Dieback ◽  
Pest Infestation ◽  
One Year ◽  
Optimal Site

Abstract The aim of this study was to analyse changes in the health status of ash stands belonging to the age classes VI and VIII growing in optimal site conditions and to compare the ash dieback with other age classes in the Jesionowe Góry Nature Reserve. Our research was conducted during the growing season in 2006 and 2007 on 22 permanent and 54 temporary sample plots. The health condition of the stands and the structure of natural regeneration were determined with a one-year interval. The amount of damage was defined using leaf loss, pest infestation and shoot dieback. Based on our estimation of natural regeneration, the capability for stand evolution in the future was determined.

scholarly journals Invasive Populations of Emerald Ash Borer Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae) in Saint Petersburg, Russia: a “Hitchhiker”?

2021 ◽  
Author(s):  
Andrey V. Selikhovkin ◽  
Boris G. Popovichev ◽  
Sergey A. Merkuryev ◽  
Mark G. Volkovitsh ◽  
Rimvys Vasaitis ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Emerald Ash Borer ◽  
Agrilus Planipennis ◽  
The Baltic Sea ◽  
Long Distance ◽  
Ash Dieback ◽  
Saint Petersburg ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
The Baltic

Emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle of East Asian origin that in North America and Russia killed millions of ash trees (Fraxinus spp.). In September 2020, EAB was de-tected in Saint Petersburg, becoming resonant event for the metropolitan city. The aim of the present study was to investigate occurrence and ecology of EAB in Saint Petersburg. The presence of two distinct enclave populations of EAB was revealed, each of which has (very likely) been established by separate events of “hitchhiking” transport vehicles. Following the invasion, further spread of EAB in Saint Petersburg was slow and locally restricted, main explanation for which is climatic factor. Due to spread by “hitchhiking”, the possibility of EAB further long-distance ge-ographic spread of EAB in the Baltic Sea region (EU) is high, and not only by ground transport (120–130 km distance from EU borders), but also by ferries transporting cars (traditional means of transportation across the Baltic Sea). In certain cases, development of EAB on F. excelsior was more successful (stem portion colonized, larval densities, number of galleries, exit holes, viable larvae, emerged beetles) than in (adjacent) F. pennsylvanica trees. Observed relatively high EAB-sensitivity of F. excelsior therefore questions the efficacy and benefits of the currently ongoing selection and breeding projects against ash dieback (ADB), caused by Hymenoscyphus fraxineus. Inventory, mapping, and monitoring of surviving F. excelsior trees in areas infested by both ADB and EAB are necessary to acquire genetic resource for work on strategic long-term restoration of F. excelsior, tackling (inevitable) invasion of EAB to the EU.

Canditate metabolites for ash dieback tolerance in Fraxinus excelsior

2020 ◽  
Vol 71 (19) ◽  
pp. 6074-6083 ◽  
Author(s):  
Miguel Nemesio-Gorriz ◽  
Riya C Menezes ◽  
Christian Paetz ◽  
Almuth Hammerbacher ◽  
Marijke Steenackers ◽  
...  
Keyword(s):  
Fungal Growth ◽  
Fraxinus Excelsior ◽  
Bark Extract ◽  
High Susceptibility ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
Fungal Growth Inhibition ◽  
Increased Susceptibility

Abstract Ash dieback, a forest epidemic caused by the invasive fungus Hymenoscyphus fraxineus, threatens ash trees throughout Europe. Within Fraxinus excelsior populations, a small proportion of genotypes show a low susceptibility to the pathogen. We compared the metabolomes from a cohort of low-susceptibility ash genotypes with a cohort of high-susceptibility ash genotypes. This revealed two significantly different chemotypes. A total of 64 candidate metabolites associated with reduced or increased susceptibility in the chemical families secoiridoids, coumarins, flavonoids, phenylethanoids, and lignans. Increased levels of two coumarins, fraxetin and esculetin, were strongly associated with reduced susceptibility to ash dieback. Both coumarins inhibited the growth of H. fraxineus in vitro when supplied at physiological concentrations, thereby validating their role as markers for low susceptibility to ash dieback. Similarly, fungal growth inhibition was observed when the methanolic bark extract of low-susceptibility ash genotypes was supplied. Our findings indicate the presence of constitutive chemical defense barriers against ash dieback in ash.

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