scholarly journals Advances in the Detection of Emerging Tree Diseases by Measurements of VOCs and HSPs Gene Expression, Application to Ash Dieback Caused by Hymenoscyphus fraxineus

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1359
Author(s):  
Piotr Borowik ◽  
Tomasz Oszako ◽  
Tadeusz Malewski ◽  
Zuzanna Zwierzyńska ◽  
Leszek Adamowicz ◽  
...  
Keyword(s):  
Electronic Nose ◽  
Root Rot ◽  
Natural Infection ◽  
Root Systems ◽  
Ash Dieback ◽  
Disease Symptoms ◽  
Tree Diseases ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
Armillaria Gallica

Ash shoot dieback has now spread throughout Europe. It is caused by an interaction between fungi that attack shoots (Hymenoscyphus fraxineus) and roots (Armillaria spp., in our case Armillaria gallica). While detection of the pathogen is relatively easy when disease symptoms are present, it is virtually impossible when the infestation is latent. Such situations occur in nurseries when seedlings become infected (the spores are carried by the wind several dozen miles). The diseases are masked by pesticides, fertilisers, and adequate irrigation to protect the plants. Root rot that develops in the soil is also difficult to detect. Currently, there is a lack of equipment that can detect root rot pathogens without digging up root systems, which risks damaging trees. For this reason, the use of an electronic nose to detect pathogens in infected tissue of ash trees grown in pots and inoculated with the above fungi was attempted. Disease symptoms were detected in all ash trees exposed to natural infection (via spores) in the forest. The electronic nose was able to detect the pathogens (compared to the control). Detection of the pathogens in seedlings will enable foresters to remove diseased trees and prevent the path from nursery to forest plantations by such selection.

scholarly journals Identification and characterization of the fungus Dothiorella sarmentorum on necrotic shoots of declining ash in Slovakia

2018 ◽  
Vol 45 (1) ◽  
pp. 53-57
Author(s):  
Helena Ivanová
Keyword(s):  
Abiotic Factors ◽  
Seed Orchard ◽  
Economic Consequences ◽  
Cumulative Effects ◽  
Disease Symptoms ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
Branch Dieback ◽  
Identification And Characterization

Abstract Formerly, before the current Hymenoscyphus fraxineus epidemic, symptomatic ash twigs were habitually colonized by fungi occurring occasionally in the early stages of ash diseases. Some of these fungi are endophytes or facultative parasites. The segments of diseased shoots of the studied trees were collected from a seed orchard situated in southwest Slovakia. The frequently isolated fungus Dothiorella sarmentorum was identified microscopically and characterized with the aid of morphological keys. The disease symptoms comprise wood cankers, bud necrosis, and shoot and branch dieback displayed through bleached, necrotic or discoloured canes in infected trees. Despite the Dothiorella species has not yet been recognized to have significant economic consequences, the cumulative effects of various stressful biotic and abiotic factors may induce disorder and decline of ash trees in Slovakia.

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.

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 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.

scholarly journals Woolly Ash Aphid Prociphilus Fraxinifolii (Riley, 1879) (Hemiptera: Eriosomatidae), A New Invasive Alien Pest of Ash Trees (Fraxinus) in Russia

2018 ◽  
Author(s):  
Andrzej Bieńkowski ◽  
Marina Orlova-Bienkowskaja
Keyword(s):  
Emerald Ash Borer ◽  
First Record ◽  
Agrilus Planipennis ◽  
Moscow Region ◽  
Invasive Pest ◽  
Fraxinus Pennsylvanica ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
Ash Trees ◽  
Alien Pest

Woolly ash aphid or ash leaf curl aphid Prociphilus fraxinifolii (Riley, 1879) is an alien invasive pest of ash trees native to North America. After its first record in Europe in 2003 in Hungary it has spread to the Ukraine, Serbia, Bulgaria, Great Britain, Spain, Poland and Germany. In 2016 P. fraxinifolii was firstly recorded at the southwestern border of Russia. Now Prociphilus fraxinifolii is firstly recorded in the center of European Russia, namely in Moscow Region, which is more than 700 km far from all other known localities of the species. In September 2017 five groups of ash trees (Fraxinus pennsylvanica) with colonies of Prociphilus fraxinifolii were found in Moscow Region. The example of Prociphilus fraxinifolii shows that alien pest insects can spread in Europe very quickly. Now Moscow region is the only regions of Europe, where the expanding range of Prociphilus fraxinifolii has overlapped with expanding ranges of other invasive alien species established in Europe in the last 20 years and severely damaging ash trees: ash dieback fungus Hymenoscyphus fraxineus Baral et al., 2014 (Ascomycota) and emerald ash borer Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae).

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 Spread and Severity of Ash Dieback in Switzerland – Tree Characteristics and Landscape Features Explain Varying Mortality Probability

2021 ◽  
Vol 4 ◽  
Author(s):  
Stefan Klesse ◽  
Meinrad Abegg ◽  
Sven E. Hopf ◽  
Martin M. Gossner ◽  
Andreas Rigling ◽  
...  
Keyword(s):  
Mortality Rates ◽  
National Forest Inventory ◽  
Mean Annual Precipitation ◽  
Soil Conditions ◽  
Comprehensive Overview ◽  
Ash Dieback ◽  
Rate Dependent ◽  
Hymenoscyphus Fraxineus ◽  
Mortality Probability ◽  
Ash Trees

Since the 1990s the invasive fungus Hymenoscyphus fraxineus has been threatening European ash (Fraxinus excelsior), a tree species with high ecological and economic importance. This pathogen is causing severe crown dieback, leading to high mortality rates across Europe and is present in Switzerland since 2008. In this study, we provide a comprehensive overview of the temporal evolution of crown damage and mortality rates in Switzerland over the 2009–2019 period. Harnessing the power of the annualized design of the Swiss national forest inventory (NFI), we show that annual mortality rates (AMRs) of ash increased significantly since the arrival of the fungus, with stronger effects in small trees [<26 cm diameter at breast height (DBH)]. Mortality modeling confirmed a size and growth-rate dependent mortality probability (MP). It also revealed that stands with higher humidity – either through higher mean annual precipitation or more humid soil conditions – showed also increased MP. Decreasing host abundance with increasing elevation was also associated with lower MP. Special ash surveys performed over the last 10 years still show a large percentage of ash trees with very low defoliation. This gives hope to finding possible tolerant or resistant trees for (inter-)national breeding programs. In the mean-time our results reinforce previously published management guidelines to promote not only healthy big trees, but also healthy and fast-growing young trees in more open stands for long-term conservation of ash in Europe.

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