Ash dieback caused by Hymenoscyphus pseudoalbidus in a seed plantation of Fraxinus excelsior in Austria

2012 ◽  
Vol 4 (9) ◽  
Author(s):  
Thomas Kirisits
Keyword(s):  
Fraxinus Excelsior ◽  
Ash Dieback ◽  
Hymenoscyphus Pseudoalbidus

scholarly journals First Report of the Ash Dieback Pathogen Hymenoscyphus pseudoalbidus (Anamorph Chalara fraxinea) on Fraxinus excelsior in Belgium

Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 220-220 ◽  
Author(s):  
A. Chandelier ◽  
N. Delhaye ◽  
M. Helson
Keyword(s):  
Fraxinus Excelsior ◽  
Malt Extract ◽  
Internal Transcribed Spacer Region ◽  
Ash Dieback ◽  
Fungal Isolation ◽  
First Report ◽  
Chalara Fraxinea ◽  
Fungal Biology ◽  
Hymenoscyphus Pseudoalbidus ◽  
Branch Dieback

Since the early 1990s, European ash (Fraxinus excelsior L.) has been affected by a lethal disease caused by the ascomycete fungus, Hymenoscyphus pseudoalbidus, originally known under the name of its anamorph, Chalara fraxinea (2,4). Pathogenicity of H. pseudoalbidus was demonstrated by inoculations on young trees (3). This emerging pathogen induces necrosis of leaf rachises, leaf wilting and shedding, bark necrosis, and wood discoloration as well as shoot, twig, and branch dieback. First observed in Poland, ash dieback now occurs in many parts of Europe. Since 2009, a survey of ash dieback caused by H. pseudoalbidus has been conducted in Wallonia (southern Belgium). Sampling units were selected to take the occurrence of ash stands and the potential points of entry of the pathogen into the country (nurseries, sawmills, rivers, and roads) into account. While the disease was not detected in 2009, young, naturally regenerated trees displaying typical symptoms of ash dieback were found in June 2010 in Silly, a village in the province of Hainaut. Symptomatic trees were located along a road in front of a large ash stand. Examination of shoots with bark necrosis from three symptomatic trees yielded positive results on the basis of a real time PCR test developed in our laboratory for the detection of H. pseudoalbidus (1). To confirm the molecular identification, fungal isolation from discolored wood onto malt extract agar supplemented with 100 mg liter–1 of streptomycin sulfate was attempted. After 18 days at 20 to 22°C in the dark, slow-growing, dull white colonies with gray patches, resembling those of C. fraxinea, had formed. The nuclear ribosomal internal transcribed spacer region (ITS) was amplified with primers ITS1 and ITS4 (4) and partly sequenced (GenBank Accession No. FR667687). A BLASTn search in GenBank revealed that the sequence of the Belgian isolate (452 bp) displayed 100% identity with sequences of a H. pseudoalbidus isolate from Switzerland (GenBank Accession No GU586932). In contrast, the sequence showed some mismatches with that of the closely related and probably strictly saprotrophic fungus, Hymenoscyphus albidus (GenBank Accession No GU586891.1). The strain was deposited as reference material in the Fungal Biology collection (CBS 128012). To our knowledge, this is the first report of ash dieback caused by H. pseudoalbidus in Belgium. The discovery of this aggressive tree pathogen in Wallonia documents its further westward spread in Europe. In the future, we expect that H. pseudoalbidus will continue its range expansion into areas that have so far not been affected by ash dieback. References: (1) A. Chandelier et al. For. Pathol. 40:87, 2010. (2) T. Kowalski. For. Pathol. 36:264, 2006. (3) T. Kowalski and O. Holdenrieder. For. Pathol. 39:1, 2009. (4) V. Queloz et al. For. Pathol. Online publication. doi:10.1111/j.1439-0329.2010.00645.x, 2010.

scholarly journals The occurrence of Hymenoscyphus pseudoalbidus apothecia in the leaf litter of Fraxinus excelsior stands with ash dieback symptoms in southern Poland

2013 ◽  
Vol 48 (2) ◽  
pp. 135-146 ◽  
Author(s):  
Tadeusz Kowalski ◽  
Maciej Białobrzeski ◽  
Agnieszka Ostafińska
Keyword(s):  
Leaf Litter ◽  
Disease Process ◽  
Fraxinus Excelsior ◽  
Ash Dieback ◽  
Disease Symptoms ◽  
Southern Poland ◽  
Chalara Fraxinea ◽  
Hymenoscyphus Pseudoalbidus

The paper presents the results of a study performed in 28 ash stands located in Myśleniece and Dynów Forest Districts in southern Poland. The intensity of <em>Fraxinus excelsior </em>disease process was estimated based on the disease symptoms analysis of 1400 trees. The amount of infectious material of <em>Hymenoscyphus pseudoalbidus </em>(anamorph <em>Chalara fraxinea</em>) was estimated by the leaf litter examination on 166 square (0.5 × 0.5 m) plots. The total number of ash leaf rachises and apothecia were counted. The analysis shows that the estimated number of <em>H. pseudoalbidus </em>apothecia may reach from 370 thousand to over 13 million per hectare at a time.

scholarly journals Impact of Fraxinus excelsior dieback on biota of ash-associated lichen epiphytes at the landscape and community level

2019 ◽  
Vol 29 (2) ◽  
pp. 431-450 ◽  
Author(s):  
Anna Łubek ◽  
Martin Kukwa ◽  
Patryk Czortek ◽  
Bogdan Jaroszewicz
Keyword(s):  
Tree Species ◽  
Landscape Scale ◽  
Community Level ◽  
Fraxinus Excelsior ◽  
Epiphytic Lichens ◽  
Ash Dieback ◽  
Epiphytic Lichen ◽  
Alternative Hosts ◽  
Rich Diversity ◽  
Lichen Biota

Abstract The landscape-scale extinction of a tree species may have a negative impact on diversity of associated epiphytic species. We used ordination and hierarchical clustering methods to assess landscape and the community level effects of reduction in the abundance of European ash Fraxinus excelsior, caused by ash dieback, on the associated epiphytic lichen biota in Białowieża Forest (Poland)—the best preserved forest complex in Central Europe. At the landscape level ash decline impact on the biota of ash-associated epiphytic lichens was weak, due to the high diversity of tree species, which may serve as potential alternative hosts. At this level, oak and hornbeam are the most important alternative hosts, assuring the maintenance of ash-associated epiphytic lichens. Lime, alder, and hazel appeared to be less important but still may serve as substitute phorophytes to approximately 2/3 of the ash-associated lichen biota. About 90% of epiphytic biota are likely to survive on the landscape scale. However, at the community level of alder-ash floodplain forest, where ash was dominant, about 50% of ash-associated epiphytic lichen species are threatened by ash dieback. Our results highlight the importance of a spatial scale in conservation biology. Protection of large forest areas with rich diversity of phorophyte trees increases chances of survival of the associated epiphytic organisms.

scholarly journals Ash pollen allergy and aerobiology

2019 ◽  
Vol 28 (7) ◽  
pp. 289-298 ◽  
Author(s):  
Markus Gassner ◽  
Peter Schmid-Grendelmeier ◽  
Bernard Clot
Keyword(s):  
School Children ◽  
Solid Phase ◽  
Birch Pollen ◽  
Pollen Allergy ◽  
Fraxinus Excelsior ◽  
Screening Tests ◽  
Fraxinus Americana ◽  
Ash Dieback ◽  
Pollen Emission ◽  
Pollen Concentrations

Abstract Background Allergy to ash pollen is common in some parts of Europe. Sensitization is overlooked if Oleaceae pollen allergens are not included in screening tests. Methods Between 1983 and 2007, sensitization to aeroallergens was systematically investigated using serological methods in 15-year-old school children (Immuno-CAP [carrier polymer] test). Samples from 1986 and 2006 were also tested using the immuno-solid-phase allergen chip (ISAC) assay. School children with sensitizations in 1986 were retested in 2010. Airborne pollen concentrations were determined by the Swiss pollen measuring network. Results Sensitization (>0.7 kU/l) to ash pollen (Fraxinus americana t15)—16.3% (102/627)—was more frequent than to birch pollen (Betula verrucosa t3): 15.3% (96/627). ISAC assays performed in children in 1986 and 2006 revealed higher molecular seroprevalence for nOle e 1 (15%; 15/100) compared to rBet v 1 (12%; 12/100). Followed-up subjects (age, 39) showed an increase in sensitizations to ash pollen. IgE levels to pollen from indigenous ash (Fraxinus excelsior t25) were higher than to pollen from American ash (Fraxinus americana t15). Low ash pollen emission levels were recorded at all measuring sites in Switzerland every 2–4 years. The infection of ashes by Chalara fraxinea resulted in increased emission of ash pollen. Conclusion Symptoms in individuals sensitized to ash pollen vary according to the pollen count and may be masked by pollen from other trees that flower at the same time of year. Sensitization to ash/Ole e 1 can be higher than to birch/Bet v 1. The determination of IgE to common ash (Fraxinus excelsior) is more sensitive than to American ash (Fraxinus americana). Ash dieback due to Chalara appears to increase pollen emission. Allergies to ash pollen can be significantly underestimated due to a failure to (correctly) identify them; they can also be masked by other pollen families (birch). Harmful organisms such as Chalara can intensify pollen emissions at least temporarily.

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