Czesław Bartnik

Pinus mugo plays a significant ecological role in the natural environment at high altitudes in the mountains including the Alps, Pyrenees, Carpathians, and Balkans. In such severe conditions, it is subjected to the harmful effects of various abiotic and biotic factors. In one of the areas of its natural occurrence in Tatra Mts. (southern Poland), for the last few years, a significant intensification of needle disease has been observed. Symptoms similar to those recorded in Tatra Mts. also occur on other Pinus species in Europe and North America, where they are caused by fungi belonging to the genus Elytroderma, Lophodermella, Lophophacidium or Ploioderma (Rhytismataceae). The current paper presents the results of research which was mainly aimed at characterization of disease symptoms observed for the first time in Poland on P. mugo needles, and identification of the main causal agent with use of the morphological and molecular technique. Based on the analyses performed at different times of the year (2015–2020), it was found that dieback symptoms initially appeared only on first-year needles, a few weeks after their development. Symptoms occur on one or both needles in the bundle. The distal parts of the needles died, while the basal parts remained green. In the following year, mainly in June and July, on the previous year’s needles attached to the shoots, mature ascomata can be seen. The fungus Lophodermella sulcigena has been identified as the cause of these symptoms. So far, the related species L. conjuncta has not been found. The morphological features of the pathogen microstructure produced on P. mugo needles are presented. Attention was drawn to certain features that may make its identification difficult, especially in terms of shapes and sizes of ascospores. The phylogenetic position of the identified causal agent in relation to closely related other species was determined. The current results confirmed that L. sulcigena shows great phylogenetic similarity to L. montivaga, which is found in North America. Nine rDNA barcode sequences of L. sulcigena obtained in this work will enrich the NCBI GenBank database. The obtained results, indicating the presence of other fungi in L. sulcigena ascomata, which may limit the spread of its ascospores, were also discussed.

Dwarf mountain pine, Pinus mugo, is an important component of the subalpine and alpine zone in Europe. For several years, in one of the natural areas of the occurrence of this species in the Polish Tatras, an intensified decline of the assimilation apparatus has been observed. The studies conducted in 2016–2020 were aimed at determining the types of disease symptoms occurring on P. mugo needles and at identifying the species composition of fungi within symptomless and diseased needles. We isolated 57 taxa from 6 types of disease symptoms and from needles without disease symptoms, identified on the basis of morphological features and molecular analyses. Absolute parasites were represented by only one species of Coleosporium senecionis, which was identified by the aecium stage. The genus Lophodermium was represented by three species: L. conigenum, L. corconticum and L. pini-mugonis. So far, L. corconticum was known only from the Karkonosze Mountains in Poland, and L. pini-mugonis from the German Alps. In addition, the more frequently isolated species included: Sydowia polyspora, Hendersonia sp., Nemania serpens, Leptomelanconium allescheri, Cladosporium spp., Biscogniauxia nummularia and Alternaria spp. Some taxa were associated with only one type of disease symptom, while some species of fungi were found to be associated with different symptoms. Twelve species of fungi were isolated from living symptomless needles, some of which were subsequently found in association with nectrotic areas on needles, e.g., Lophodermium corconticum, L. conigenum and Leptomelanconium allescheri. L. pinastri has not been found in the present studies. In the discussion, an attempt was made to assess the role of some of the identified species of fungi in causing the disease process of P. mugo needles.

Quantification of total phenolic compounds in the heartwood of Picea abies using the Folin–Ciocalteu methods showed that concentrations of phenolic compounds in the heart‐ and sapwood of Picea abies varied, depending on the decay class to which boles were allocated. In the heartwood, mean phenolic concentration was 3.28 mg/g, compared with 2.44 mg/g in sapwood. Experiments using different concentrations of phenolic compounds showed that Heterobasidion parviporum is more sensitive to the effects of phenolic compounds found in sapwood, and less sensitive to phenolic compounds found in heartwood. The high concentration of phenolic compounds extracted from spruce stimulated the decomposition of wood by Armillaria ostoyae. This demonstrates the great ability of A. ostoyae to metabolize phenolic compounds. This is confirmed by natural conditions, where A. ostoyae attacks mainly sapwood and H. parviporum attacks heartwood of P. abies. In heartwood, the average antioxidant activity was approximately 10% higher than in the sapwood. The extraction process and presence of amino acids and reducing sugars might influence on the results. The results suggest that timber quality monitoring in spruce stands could be partly based on measurements of phenol compound concentrations in sapwood, as the technique enables prediction of the potential impact of decay fungi early in succession.

This study describes the first observation of Botryodiplodia canker in the Western Carpathians in south‐eastern Poland caused by Botryodiplodia hypodermia (Sacc.) Petr. (syn. Sphaeropsis hypodermia, S. ulmicola). The canker occurred on an approximately 17‐year‐old Ulmus glabra sapling in a mixed conifer/deciduous stand with elm trees severely damaged by Dutch elm disease. This paper describes disease symptoms and provides information on the macro‐ and micromorphology of the fungus isolated from the cankered tissues. The results of BLAST search using DNA sequences obtained for our cultures and subsequent phylogenetic positioning of the fungus among closely related Botryosphaeriaceae indicate that the species is much more closely related to Phaeobotryon than to the other Botryodiplodia or Sphaeropsis species. Moreover, a total of 16 polymorphisms within the ITS region were detected between S. ulmicola associated with Botryodiplodia canker in North America and B. hypodermia associated with the canker observed in Poland. Thus, the “European” variant of “Sphaeropsis” ulmicola can now be easily identified with our barcode sequences. The Botryodiplodia canker is much less prevalent in Europe than in North America. Differences in virulence of “American” and “European” linages and differences in susceptibility of various elm species may be the reason for the higher prevalence of the disease in North America.

Summary: Leptomelanconium allescheri was identified for the first time in Poland in 2016 in the Tatra Mts. on Pinus mugo needles. It produced numerous conidiomata on necrotic lesions on live needles. In our study, we provide detailed characteristics of disease symptoms and describe morphology of the structures of the fungus. The shape and size of macroconidia are proven to be more variable in vitro than in situ. The malt extract agar colonies of the fungus obtained from germinating macroconidia are described for the first time. Our observations prove also that, apart from macroconidia, L. allescheri produces in vitro unicellular, hyaline microconidia, 3.5–10 × 1.8–5.0 μm in size, the previously unknown aspect in the development cycle of this species. The BLAST search with ITS and LSU sequences of L. allescheri resulted in the closest match with Cenangium acuum accessions (94%–95% and 99%, respectively). Two gene based, LSU plus ITS, phylogenetic positioning of L. allescheri proves that it belongs to Pezizomycotina, Helotiales. Further, on family level, placement of L. allescheri, as well as its two closest species C. acuum and Piceomphale bulgarioides, remains undefined. The L. allescheri barcode sequences (accession numbers: ITS—MF573935, LSU—MF573936, IGS—MF573937) and cultures were submitted to NCBI GenBank and CBS Utrecht, The Netherlands culture collection.

The paper describes, for the first time, the occurrence of the entomopathogenic fungus Cordyceps bassiana (anamorph: Beauveria bassiana) on the imago of the endangered beetle Rosalia longicorn Rosalia alpina from the Low Beskid Mountains (the Carpathians, SE Poland). Furthermore, an isolate of the saprotrophic fungus Hypoxylon fragiforme was obtained as a result of laboratory tests on R. alpina specimens. Relationships between the identified fungi and R. alpina are discussed.

In central Europe, the endangered Rosalia longicorn Rosalia alpina (L.) has rarely been observed to develop in the wood of elms Ulmus sp.; however, this beetle has recently expanded into habitats formed by elms. The factors driving these changes are unknown in detail, but a potential one is the increasing amount of breeding material, namely, dead elm wood. Dutch elm disease, caused by the fungi Ophiostoma ulmi and O. novo-ulmi, by killing off elm trees, has created a supply of dead wood. The aim of this work was to assess the potential role of Dutch elm disease in the formation of habitats suitable for the endangered Rosalia longicorn. The health of four elm stands (Carpathians, SE Poland) was analysed and the pathogen responsible for elm death were determined by DNA sequence comparison. O. novo-ulmi — the causative agent of Dutch elm disease — was isolated from weakened and dying trees at all studied localities. In total, 30% of the elm trees were dead, 34% showed signs of dieback or were moribu...

Results of the first studies in Poland on Cristulariella depraedans, the causal agent of necroses on tree and shrub leaves, are presented. The fungus was recorded on Acer platanoides, A. pseudoplatanus and eight other species of trees and shrubs, including Corylus avellana, Fagus sylvatica, Lonicera xylosteum and Padus avium that were not previously known as hosts of the fungus. The disease symptoms, which depend on the host plant species, the size and number of necrotic lesions on leaves, and the morphological features of the fungal propagules were characterized.

The present paper presents the results of long-term observations of differences in growth and morphology of colonies of C. fraxinea isolated from ash stems with symptoms of dieback and the results of studies on effects of temperature on growth and morphology of colonies in vitro. Thirty randomly chosen C. fraxinea cultures, originating from six Forest Districts in southern and northern Poland, viz. Andrychów, Gryfice, Kańczuga, Lębork, Miechów and Mircze, were included in the temperature assay. Colony growth and morphology were evaluated in vitro, on malt extract agar. Two replicates of each isolate were incubated at 5, 10, 15, 20, 25 and 30°C in darkness. Colonies of C. fraxinea isolated from necrotic stem tissues of diseased ash trees differed greatly in colour, structure, growth rate, presence of sectors and stromata as well as the intensity of conidial sporulation. Colony characters were often lost in further sub-cultures grown on the same medium. Colonies of C. fraxinea grew at 5-25°C in vitro. Three isolates still grew, though slowly, at 30°C. The optimum temperature for growth was 20°C. Among 30 isolates tested, five grew most quickly at 25°C and four at 15°C. Differences among colony diameters recorded at 5, 10, 15, 20 and 30°C were statistically significant, while differences at 15 and 25°C were not. At some temperatures, statistically significant differences in growth rate were related to the origin of the isolates. There were three main colony colour types. Temperature was the main factor affecting colony morphology in vitro. The formation of sectors was observed in 36% of colonies, pseudoparenchymatous stromata in 10.4% of colonies, and white crystalline substances in 53.3% of colonies. The results of in vitro observations were used for discussion of the effects of temperature on growth and activity of C. fraxinea in vivo.