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

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.

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Host Range of Hymenoscyphus fraxineus in Slovak Arboreta

Forests ◽

10.3390/f11050596 ◽

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.

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Diversity of secoiridoid glycosides in leaves of UK and Danish ash provide new insight for ash dieback management

Scientific Reports ◽

10.1038/s41598-020-76140-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

John D. Sidda ◽

Lijiang Song ◽

Jack L. Parker ◽

David J. Studholme ◽

Christine Sambles ◽

...

Keyword(s):

Emerald Ash Borer ◽

Structural Diversity ◽

Feeding Deterrents ◽

Leaf Extracts ◽

Ash Dieback ◽

Sample Group ◽

Ash Trees ◽

Secoiridoid Glycosides ◽

The Uk ◽

European Ash

Abstract Secoiridoid glycosides are anti-feeding deterrents of the Oleaceae family recently highlighted as potential biomarkers in Danish ash trees to differentiate between those tolerant and susceptible to the fungal disease ash dieback. With the knowledge that emerald ash borer has recently entered Europe from Russia, and that extensive selection trials are ongoing in Europe for ash dieback tolerant European ash (Fraxinus excelsior), we undertook comprehensive screening of secoiridoid glycosides in leaf extracts of trees tolerant and susceptible to ash dieback sampled from sites in the UK and Denmark. Here we report an unexpected diversity of secoiridoid glycosides in UK trees and higher levels of secoiridoid glycosides in the UK sample group. While it is unlikely that secoiridoid glycosides generally can serve as reliable markers for ash dieback susceptibility, there are differences between tolerant and susceptible groups for specific secoiridoids. We predict that the high levels—and structural diversity—of secoiridoids present in the UK group may provide a robust reservoir of anti-feeding deterrents to mitigate future herbivore threats such as the Emerald ash borer.

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

Forests ◽

10.3390/f11060617 ◽

2020 ◽

Vol 11 (6) ◽

pp. 617 ◽

Cited By ~ 1

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.

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‘I’d like to report a suspicious looking tree’: Public concern, public attention and the nature of reporting about ash dieback in the United Kingdom

Public Understanding of Science ◽

10.1177/0963662518814369 ◽

2018 ◽

Vol 28 (3) ◽

pp. 339-356 ◽

Cited By ~ 2

Author(s):

John Fellenor ◽

Julie Barnett ◽

Clive Potter ◽

Julie Urquhart ◽

J. D. Mumford ◽

...

Keyword(s):

United Kingdom ◽

Policy Development ◽

Public Concern ◽

Public Attention ◽

Ash Dieback ◽

The United Kingdom ◽

Phone Calls ◽

The Media ◽

The Uk ◽

Policy Attention

‘Public concern’, a ubiquitous notion used in descriptive and explanatory modes by policy makers, academics and the media, is often presented as axiomatic. However, the variability with which it is deployed in different contexts, for example, as justification for policy attention or having equivalence with what is considered ‘newsworthy’, belies this status. This article presents an empirical analysis of emails and phone calls from the UK public to UK government agencies, reporting suspected cases of ash dieback disease – a tree health issue which attracted intense media and policy attention in the United Kingdom in 2012. We challenge the view that public attentiveness is necessarily indicative of public concern, or that media attention can be taken as its proxy. Examination of concern at macro and micro levels reveals heterogeneous processes with multiple dimensions. Understanding the nature of public concern is crucial in enabling more effective policy development and operational responses to risk-related issues.

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Trapping Aliens: Understanding the Complexities of Controlling Introduced Freshwater Crayfish in the United Kingdom

Transylvanian Review of Systematical and Ecological Research ◽

10.1515/trser-2015-0086 ◽

2016 ◽

Vol 18 (2) ◽

pp. 39-52

Author(s):

Emily Adams

Keyword(s):

Native Species ◽

Freshwater Crayfish ◽

Barriers To Success ◽

East Anglia ◽

The United Kingdom ◽

The People ◽

Freshwater Habitats ◽

The Uk ◽

Native Crayfish ◽

Interdisciplinary Study

Abstract Invasive non-native species pose practical and ethical problems for the people tasked with their management. Invasive freshwater crayfish species in the UK threaten rare native crayfish and freshwater habitats, yet their control is beset with social, practical and environmental barriers to success. This paper draws on an interdisciplinary study of stakeholders involved in crayfish management in East Anglia to explore the management of non-native freshwater crayfish in the UK. It concludes that when standard methods of control fail, stakeholders are willing to consider unusual management suggestions such as commercial trapping, whilst recognising that these may bring their own problems.

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The impact of ash dieback on veteran trees in southwestern Sweden

BALTIC FORESTRY ◽

10.46490/bf558 ◽

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

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

Forestry Studies / Metsanduslikud Uurimused ◽

10.2478/fsmu-2020-0013 ◽

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.

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

10.20944/preprints202109.0252.v1 ◽

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.

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Canditate metabolites for ash dieback tolerance in Fraxinus excelsior

Journal of Experimental Botany ◽

10.1093/jxb/eraa306 ◽

2020 ◽

Vol 71 (19) ◽

pp. 6074-6083 ◽

Cited By ~ 3

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

10.1101/254078 ◽

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).

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