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Vertical gradient of Hymenoscyphus fraxineus spore dispersal at infected locality in Boršov nad Vltavou
ŠTOIDL, Petr
Hymenoscyphus fraxineus is a pathogenic sac fungus causing ash tree necrosis throughout Europe, spreading predominantly through the air using ascospores. The aim of this thesis was to quantitatively describe the occurrence of spores of the causative agent of ash trees necrosis at different heights above the source of infection. The results were subsequently used to consider the inoculum potential of this pathogenic fungus for longer distance spreading using air currents. The qPCR method was used for the detection and quantification of DNA concentration. Based on a statistical analysis of the obtained molecular data a dependence of the occurrence of different amounts of H. fraxineus on height was proved. The main contribution of this thesis lies in charting the range of the H. fraxineus pathogen spread in the air column which is directly related to the range of spores to greater distances.
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Posouzení zdravotního stavu a dendrometrických charakteristik Kočárové aleje, Frýdlant
Soukup, Vojtěch
ABSTRACT The assessment of health condition and dendrometric characteristics in Kočárová alej (Carriage alley) in Raspenava. The aim of this work is the assessment of health condition of an alley in Raspenava, the detection of main insect pests and tree diseases and a subsequent comparison with the assessment of relicts of felling of this alley. Trees planted along roads by our ancestors are integral parts of our landscape. Carriage alleys were in the past planted in particular for an improvement of the transport of carriages. However, the development of transport caused that alleys are currently considered to be obstacle or hazardous to still increasing automobile transport. This problem is in extreme cases solved through felling of old trees and their replacement with a new planting pursuant to valid standards concerning the distance of trees planted along communications. However it often results in breach of planned compensatory planting due to an excessive interference with plots neighbouring with the communication. The aim of this work is the assessment of the necessity of performed intervention in relation to the health condition of trees.
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Sensitivity of Czech provenances of European common ash and narrow-leaved ash to invasive pathogen Hymenoscyphus fraxineus
Kraus, Marek ; Pešková, Vítězslava (advisor) ; Čížková, Dana (referee)
This thesis deals with a survey of provenance areas and assessment of attacking Fraxinus excelsior L. and Fraxinus angustifolia by the pathogen Hymenoscyphus fraxineus.
The aim of the thesis is to map the incidence of infected trees in these areas and to evaluate the sensitivity of the sites to the pathogen Hymenoscyphus fraxineus.
The theoretical part deals with processing of data collected during field work on selected provenance areas Koneprusy and Veltruby. Amongst the evaluated parameters there were: trunk diameter at measuring height, tree height, and especially canopy drying caused by Hymenoscyphus fraxineus. As the outcome of the survey photographs were taken and records were collected for individual trees in the provenance areas. Each of the trees has its own unique label that has accurately defined its location to prevent potential errors in data processing. The processed data was then evaluated in NCSS 8.0 software and cluster analysis was performed in order to compare the provenances. This analysis only compares the provenances, which are located in both provenance areas. The results show that no provenance without the pathogen Hymenoscyphus fraxineus attack appeared in the provenances Koneprusy and Veltruby. Subjects in 4 ŠLP Kostelec nad Černými Lesy - Svojšice and 24 LS Czech Krumlov Chvalšiny proved to be more resistant than others. Although the increase in the tree height and the trunk thickness is the largest on those areas the defoliation rate is high. It is probable that the population of these provenances will gradually die. Due to growing abbility of some individuals located in other provenances it is obvious that habitat conditions and individual resilience are key factors.
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Možnosti využití nového růstově stimulačního organického přípravku a jeho variant, pro eliminaci vývoje Chalara fraxinea
Černohousová, Jana
Pathogen Chalara fraxinea, one of the causes wasting of ash, is currently one of the most serious enemy of ash. At first, in this thesis there were summarized knowledge about Chalara fraxinea and related topics. There were addressed two main research directions. The first direction led us to the laboratory, in vitro there were addressed response of mycelium Chalara fraxinea to applied organomineral products. The second direction was concentrated in the ash stands, there were applied the same products as in the laboratory, but the products were applied on leaves of ash trees. There were examined the efficacy of products based on health assessment ash. The results should help in the fight against Chalara fraxinea.
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Occurrence of putative dsRNA mycoviruses in Ash Dieback Causal Agent
Čermáková, Vendula
Thanks to environmental changes, globalization, long distance trade and plant transport, invasive organisms have become a major threat for world biodiversity and ecosystem services. Over the last 20 years, common European ash trees (Fraxinus excelsior L., Fraxinus angustifolia Vahl. etc.) have been subjected to heavy dieback and mortality because of the introduction and spread of the ascomycetous fungal pathogen Hymenoscyphus pseudoalbidus Queloz (syn. Chalara fraxinea Kowalski). Once the disease is established, its management is hardly possible. Therefore, one of the main objectives of European researchers is to find effective and respectful control methods, such as biological control. The discovery of viruses which reduce the virulence of the chestnut blight fungus Cryphonecria parasitica (Murr.) Barr., has intensively stimulated the research of fungal viruses as potential biological control agents (BCA). The occurrence of putative dsRNA particles in the decaying fungus H. pseudoalbidus was investigated as an important indicator of the mycoviruses' presence. In total, 106 samples of this pathogen were obtained from eight different European countries. According to the results, dsRNA segments were confirmed in 32.1 % of examined samples (two similarly sized at 2--2.5 kb and a third one of approximately 5 kb). Statistical results have revealed no significant relation between the presence of dsRNA and growth rate, colour or any other characteristic of the mycelium.
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