Pachyseius Berlese 1910

Genus <i>Pachyseius</i> Berlese, 1910 <p> <i>Diagnosis</i></p> <p> <i>Dorsal idiosoma</i>. Dorsoventrally flattened, oval to oblong short-legged forms with a holodorsal shield. Dorsal shield bearing 30 pairs of setae; all dorsal setae usually uniformly formed, simple and needle-like. Bases of dorsal setae J1 adjacent and situated paraxial to setae J2. Infundibulum of glands gdj3 (also gdZ1 and gdS4) sometimes conspicuously enlarged (hypertrophied), cavity-like and strongly sclerotized. Dorsum usually with reticulate sculptural pattern.</p> <p> <i>Ventral idiosoma</i>. Presternal shields often present. Sternal shield free and mostly with 3 pairs of setae and 2 pairs of pores. A pair of small rounded metasternal shields with a seta and pore present (in <i>P</i>. <i>morazae</i> sp. nov., metasternals fused to sternal shield). Genital shield separate, truncate posteriorly, and with 4 oval sclerites close to its posterior margin. Genital pores on or off genital shield. Large ventri-anal shield with 2–4 preanal and 3 circumanal setae present, adanal setae anterior to anus. Peritremes, peritrematal and podal shields relatively well developed. Posterior section of peritrematal shield slightly widened, abutting the exopodal shields, and not extending conspicuously beyond coxa IV. In some species (described in this paper), posterior tip of peritrematal shield fused to exopodal shield IV. Area between peritrematal shield and anterolateral corner of ventri-anal shield often with 1–3 tiny sclerites. Male with separate sterniti-genital and ventri-anal shields. In female, a pair of distinctive, narrow and elongated metapodal shields present (rarely metapodals fused to ventri-anal shield); lateral and opisthogastric cuticle usually with 6–12 pairs of setae.</p> <p> <i>Gnathosoma</i>. Hypostome relatively narrow; corniculi short and horn-like. Male palptibia without outgrowths. Palp apotele 3-tined. Epistome simple, subtriangular and with serrated lateral margins, apex pointed, truncate or widely rounded. Cheliceral spermatodactyl in male subdistal, elongated, slightly longer than movable digit, curved backward, tubular, progressively tapered distally and truncate apically. Female cheliceral digits relatively slender, movable digit bidentate, fixed digit usually with 2–4 small teeth.</p> <p> <i>Spermathecal apparatus</i>. Sperm access system tubular and associated with posterior margin of coxae III. Spermathecal tubes very long, tenuous and with slightly broadened tips.</p> <p> <i>Legs</i>. Legs normal, shorter than idiosoma. Tarsi with ambulacrum and 2 claws, tarsus II with 1–3 spur-like distal setae. Male femur II and tibia II spurred. Typical chaetotaxy as follows: coxa I–IV: 2, 2, 2, 1; trochanter I–IV: 6, 5, 5, 5; femur I–IV: 13 (2-5/4-2), 11 (2-5/3-1), 6 (1-3/1-1), 6 (1-3/1-1); genu I–IV: 12 (2-5/3-2), 11 (2- 5/2-2), 8 (2-4/1-1), 8 (2-4/1-1); tibia I–IV: 12 (2-5/3-2), 10 (2-4/2-2), 7 (1-3/2-1), 7 (1-3/2-1); tarsus II–IV: 18 (3-7/5-3), 18 (3-7/5-3), 18 (3-7/5-3). The following variations occur in the chaetotaxy of some leg segments: in <i>P</i>. <i>iraola</i>, femur I and genu II with 12 setae (2-5/3-2); in species related to <i>P</i>. <i>humeralis</i>, tarsus IV with 17 setae (3-6/5-3).</p> <p> <b> Key to the females for the world species of the genus <i>Pachyseius</i> 1 <i>)</i></b> </p> <p> 1. Ventri-anal shield with 4 pairs of pre-anal setae; anterior margin of sternal shield with one pair of strongly sclerotized and horn-like projections; length of dorsal shield 640–650 µm <i>P</i>. <i>sinicus</i> Yin, Lü & Lan, 1986</p> <p>- Ventri-anal shield with at most 3 pairs of pre-anal setae; sternal shield smooth and without horn-like projections on anterior margin............................................................. 2</p> <p>2. Ventri-anal shield with 3 pairs of pre-anal setae............................................. 3</p> <p>- Ventri-anal shield with 2 pairs of pre-anal setae............................................. 7</p> <p>3. Posterior section of peritrematal shield and exopodal shield IV fused............................ 4</p> <p>- Posterior section of peritrematal shield and exopodal shield IV not fused......................... 5</p> <p> 4. Metapodal shields greatly expanded, subtriangular, very large and with reticulate-punctate sculpture; presternal shields absent; exopodal shields III and IV well separated; length of dorsal shield 565–575 µm............................................................. <i>P</i>. <i>pachylaelapoides</i> sp. nov.</p> <p> <b>-</b> Metapodal shields normal in size, narrow and elongated; presternal shields well developed and sclerotized; exopodal shields III and IV abutting each other; length of dorsal shield 523 µm... <i>P</i>. <i>cicaki</i> sp. nov.</p> <p> 5. Presternal shields absent; peritrematal shield (close to stigma) anterior margin of dorsal shield (between setae z1 and z2) with normal pores; dorsal setae modified, spatulate; femur I and genu II with 12 setae (2- 5/3-2), tarsus IV with 18 setae (3-7/5-3); lateral and ventral soft cuticle with 12–13 pairs of setae; length of dorsal shield 805 µm............................................... <i>P</i>. <i>iraola</i> Moraza, 1993</p> <p>- Presternal shields weakly sclerotized, with fine net-like ornamentation, and connected with anterior margin of sternal shield; peritrematal shield (close to stigma) anterior margin of dorsal shield (between setae z1 and z2) with hypertrophied poroid structure; dorsal setae simple, needle-like; femur I with 13 setae (2- 5/4-2), genu II with 11 setae (2-5/2-2), tarsus IV with 17 setae (3-6/5-3); lateral and ventral soft cuticle with 8–9 pairs of setae................................................................. 6</p> <p> 6. Ventri-anal shield enlarged laterally (width: 255–300 µm), subequal in length and width (length/width: 0.96–1.07); metapodal shield closely abutting lateral margin of ventri-anal shield; lateral and ventral soft cuticle with 9 pairs of setae; length of dorsal shield 640–760 µm..... <i>P</i>. <i>wideventris</i> Afifi & Nasr, 1984</p> <p> - Ventri-anal shield oblong (not exceeding 240 µm in width), longer than wide (width: 165–235 µm, length/ width: 1.08–1.28); metapodal shield and lateral margin of ventri-anal shield well separated; lateral and ventral soft cuticle with 8 pairs of setae; length of dorsal shield 530–665 µm.. <i>P</i>. <i>humeralis</i> Berlese, 1910</p> <p> 7. Separate metapodal shields absent (metapodals fully fused with anterolateral margins of ventri-anal shield); marginal region of dorsal shield with 3 pairs of hypertrophied poroid structures; length of dorsal shield 600–715 µm........................................... <i>P</i>. <i>strandtmanni</i> Solomon, 1982</p> <p>- Separate metapodal shields present; marginal region of dorsal shield with at most one pair of hypertrophied poroid structures (between setae z1 and z2)........................................... 8</p> <p> 8. Metasternal shields fully fused with sternal shield; peritrematal shield and exopodal IV fused; peritrematal shield posteriorly expanded, truncate and abutting anterolateral margin of ventri-anal shield; length of dorsal shield 790–845 µm............................................... <i>P</i>. <i>morazae</i> sp. nov.</p> <p> <b>-</b> Metasternals and exopodals IV free; posterior tip of peritrematal shields tapered, obtusely pointed or rounded, and well separated from anterolateral margins of ventri-anal shield...................... 9</p> <p> 9. A pair of presternal shields well developed and sclerotized; metapodal shields closely abutting anterolateral margins of ventri-anal shield; ventri-anal shield subpentagonal, subequal in length and width, and with small pore close to anterolateral margins; length of dorsal shield 560–608 µm................................................................................ <i>P</i>. <i>orientalis</i> Nikolsky, 1982</p> <p> 1. <i>Pachyseius chenpengi</i> MA & YIN, 2000 is not included in the key due to inadequate original description and differential diagnosis.</p> <p>- Presternal shields absent; metapodal shields and anterolateral margins of ventri-anal shield well separated by wide strip of soft cuticle; ventri-anal shield narrow, elongated, distinctly longer than wide, and without pores close to anterolateral margins...................................................... 10</p> <p>10. Posterior tip of peritrematal shields reaching the posterior margin of exopodals IV (both with position beyond posterior margin of coxae IV); exopodal shields III and IV abutting each other............. 11</p> <p>- Posterior tip of peritrematal shields not reaching the posterior margin of exopodals IV as well as posterior margin of coxae IV (posterior margin of exopodals IV exceeding the posterior margin of coxae IV); exopodal shields III and IV not abutting each other, separated by inner projection of peritrematal shield................................................................................... 12</p> <p> 11. Dorsal setae relatively longer (e.g. setae J4 with tip reaching beyond the following setae J5 as well as posterior margin of dorsal shield) and with spatulate tips................. <i>P</i>. <i>cavernicola</i> Ishikawa, 1989</p> <p> - Dorsal setae relatively shorter (setae J4 with tip not exceeding beyond the posterior margin of dorsal shield and only barely reaching to the following setae J5), simple and needle-like; length of dorsal shield 512–600 µm....................................................... <i>P</i>. <i>angustus</i> Hyatt, 1956</p> <p> 12. Ventri-anal shield oblong, with almost parallel lateral margins, slightly wider in the anterior part; length of dorsal shield 821 µm............................................... <i>P</i>. <i>morenoi</i> Moraza, 1993</p> <p> - Ventri-anal shield suboval, widest in its middle part; length of dorsal shield 750 µm.......................................................................... <i>P</i>. <i>angustiventris</i> Willmann, 1935</p>Published as part of <i>Mašán, Peter & Mihál, Ivan, 2007, New mites of the genus Pachyseius Berlese from Bulgaria (Acari: Pachylaelapidae), pp. 59-68 in Zootaxa 1485</i> on pages 60-62, DOI: <a href="http://zenodo.org/record/176951">10.5281/zenodo.176951</a&gt

Pachyseius cicaki Mašán & Mihál, 2007, sp. nov.

<i>Pachyseius cicaki</i> sp. nov. (Figs 1–2, 6–7) <p> <i>Material Examined</i></p> <p> Holotype: Ψ, NW Bulgaria, Stara Planina Mts., Vitinya village (42°47'N, 23°48'E), beech forest (<i>Fagion sylvaticae</i>) with admixed <i>Carpinus betulus</i> (2%) and <i>Quercus</i> sp. (1%), 970 m a.s.l., April 19, 2005. Paratypes: 1 Ψ, same data as holotype; 1 Ψ, Shipkovo village (42°52'N, 24°35'E), beech forest (<i>Fagion sylvaticae</i>), 650 m a.s.l., April 25, 2006.</p> <p> <i>Description</i> (<i>Female</i>)</p> <p> <i>Dorsal idiosoma</i> (Fig. 1). Dorsal shield middle-sized, length 565–575 µm, width 305–330 µm, oblong (length/width 1.73–1.87), with simple reticulate surface pattern, and 30 pairs of simple needle-like setae. Dorsal setae relatively short, j5: 22–27 µm, J5: 23–32 µm, longest anterolateral setae: 37–43 µm. All dorsal pores normally formed, not conspicuously enlarged.</p> <p> <i>Ventral idiosoma</i> (Fig. 2). Presternal shields present, drop-like, free, strongly sclerotized, and without sculpture. Sternal shield oblong (length 144–155 µm), widely convex posteriorly, with punctiform reticulate sculptural pattern, and 3 pairs of setae and 2 pairs of pores. Metasternal shields small, oval, free in soft cuticle. Genital shield relatively short and wide (length 70–76 µm), genital pores positioned inside the shield. Ventrianal shield suboval, longer than wide, length 216–241 µm, width 193–200 µm, length/width 1.11–1.23, reticulated and bearing 3 pairs of pre-anal setae. Posterior terminal section of peritrematal shield truncate and fused to exopodal shield IV. Exopodal shield III free and abutting the peritrematal shield and exopodal IV. Area between peritrematal shield and anterolateral corner of ventri-anal shield with 2 small subequal sclerites. Metapodal shields distinctly elongate, fully free, not abutting anterolateral margins of ventri-anal shield. Lateral and opisthogastric cuticle with 8 pairs of setae.</p> <p> <i>Gnathosoma</i>. Epistome subtriangular, widened basally, tapered toward the apex, rounded apically, and finely denticulated on distal margin (Fig. 7).</p> <p> <i>Legs</i>. Tarsus II with 3 spur-like setae as in Fig. 6.</p> <p> <i>Notes</i></p> <p> On the basis of the general appearance of the ventral shields, <i>P</i>. <i>cicaki</i> sp. nov. is very similar to <i>P</i>. <i>iraola</i> described from Spain (Moraza, 1993). These two species may be separated by the fact that the exopodal shields IV in <i>P</i>. <i>cicaki</i> sp. nov. are fused to the posteriormost section of the peritrematal shields, while these shields in <i>P</i>. <i>iraola</i> are fully separate. In addition, <i>P</i>. <i>iraola</i> has no presternal shields, slightly spatulated dorsal setae and 12–13 setae situated on ventral and lateral soft cuticle. In <i>P</i>. <i>cicaki</i> sp. nov., the presternals are well developed, dorsal setae are simple and not modified, and 8 pairs of marginal and opisthogastric setae are present on the lateral and ventral soft cuticle.</p>Published as part of <i>Mašán, Peter & Mihál, Ivan, 2007, New mites of the genus Pachyseius Berlese from Bulgaria (Acari: Pachylaelapidae), pp. 59-68 in Zootaxa 1485</i> on pages 62-63, DOI: <a href="http://zenodo.org/record/176951">10.5281/zenodo.176951</a&gt

Pachyseius pachylaelapoides Mašán & Mihál, 2007, sp. nov.

<i>Pachyseius pachylaelapoides</i> sp. nov. (Figs 5, 8) <p> <i>Description</i> (<i>Female</i>)</p> <p> <i>Dorsal idiosoma</i>. Dorsal shield middle-sized (length 523 µm, width 302 µm), oblong (length/width 1.73), with delicate punctate-reticulate surface pattern, and 30 pairs of simple needle-like setae (dorsal shield almost identical to that as in Fig. 1). Dorsal setae short (j 5 18–22 µm, J 5 23–33 µm, longest anterolateral setae 25–35 µm). All dorsal pores normally formed and not conspicuously enlarged.</p> <p> <i>Ventral idiosoma</i> (Fig. 5). Presternal shields absent. Sternal shield slightly oblong (length 132 µm), widely convex and slightly truncate posteriorly, with punctiform reticulate sculptural pattern, and 3 pairs of setae and 2 pairs of pores. Metasternal shields small, oval and free in soft cuticle. Genital shield relatively short and wide (length 73 µm), genital pores positioned outside the shield. Ventri-anal shield subpentagonal, widest at the middle, slightly longer than wide (length 219 µm, width 200 µm, length/width 1.1), with reticulate-punctate ornamentation and 3 pairs of pre-anal setae. Posterior terminal section of peritrematal shield truncate and fused to exopodal shield IV. Exopodal shield III free, abutting the peritrematal shield but well separated from exopodal shield IV. Metapodal shields very enlarged, subtriangular, with punctate-reticulate pattern and a pore. Anterior and inner margins of metapodals adjacent to peritrematal and ventri-anal shields respectively. A pair of small suboval sclerites present close to anterolateral corners of ventri-anal shield. Lateral and opisthogastric cuticle with 7 pairs of setae.</p> <p> <i>Gnathosoma</i>. Epistome subtriangular, very finely denticulate on lateral margins, distal projection bluntly pointed (Fig. 8).</p> <p> <i>Legs</i>. Tarsus II with 3 spur-like setae as in Fig. 6.</p> <p> <i>Notes</i></p> <p>This new species can be easily recognized by its greatly expanded metapodal shields.</p>Published as part of <i>Mašán, Peter & Mihál, Ivan, 2007, New mites of the genus Pachyseius Berlese from Bulgaria (Acari: Pachylaelapidae), pp. 59-68 in Zootaxa 1485</i> on page 66, DOI: <a href="http://zenodo.org/record/176951">10.5281/zenodo.176951</a&gt

Pachyseius morazae Mašán & Mihál, 2007, sp. nov.

<i>Pachyseius morazae</i> sp. nov. (Figs 3–4, 9) <p> <i>Material Examined</i></p> <p> Holotype: Ψ, NW Bulgaria, Stara Planina Mts., Petrokhan village (43°07'N, 23°07'E), old beech forest (<i>Fagion sylvaticae</i>), 1,400 m a.s.l., April 20, 2005. Paratypes, 3 ΨΨ, same data as holotype.</p> <p> <i>Description</i> (<i>Female</i>)</p> <p> <i>Dorsal idiosoma</i> (Fig. 3). Dorsal shield large, length 790–845 µm, width 570–600 µm, oval to widely oval (length/width 1.38–1.42), with inconspicuous reticulation and fine granulation on surface, and 30 pairs of simple needle-like setae. Medial and posterior dorsal setae relatively short (j 5 28–34 µm, J5 40–50 µm), some anterolateral setae distinctly longer (70–85 µm). All dorsal pores normally formed, not conspicuously enlarged.</p> <p> <i>Ventral idiosoma</i> (Fig. 4). Presternal shields present, subtrapezoidal, free, strongly sclerotized, and without sculpture. Sternal shield relatively large (length 163–177 µm), approximately subequal in length and width, concave posteriorly, with punctiform reticulate sculptural pattern, and 4 pairs of setae and 3 pairs of pores. Metasternal shields, both with a seta and pore, fused to posterolateral corners of sternal shield. Genital shield relatively short and wide (length 122–140 µm), genital pores positioned outside the shield. Ventri-anal shield subcordate, subequal in length and width (length 325–343 µm, width 317–343 µm, length/width 0.96– 1.07), with punctate-reticulate sculpture and 2 pairs of pre-anal setae. Posterior terminal section of peritrematal shield truncate and fused to exopodal shield IV; a hypertrophied pore-like structure present close to stigma. Exopodal shield III free and abutting the peritrematal shield and exopodal IV. Area between peritrematal shield and anterolateral corner of ventri-anal shield narrow and bearing 2 small and subequal sclerites. Metapodal shields separate, distinctly elongate and abutting the anterolateral margins of ventri-anal shield. Lateral and opisthogastric cuticle with 11 pairs of setae.</p> <p> <i>Gnathosoma</i>. Epistome subtriangular, very finely denticulate on lateral margins, distal projection narrow and bluntly pointed (Fig. 9).</p> <p> <i>Legs</i>. Tarsus II with one massive spur-like seta.</p> <p> <i>Notes</i></p> <p>The presence of four setae on the sternal shield, the fusion of the peritrematal shields with exopodals IV, well developed presternals, as well as 2 pairs of pre-anal setae on the ventri-anal shield and size of idiosoma are good diagnostic characters for this new species.</p> <p> <i>Etymology</i></p> <p>This new species is named in honour of Maria Lourdes Moraza, who has contributed in a substantial way to the knowledge of the pachylaelapid mites of Europe.</p>Published as part of <i>Mašán, Peter & Mihál, Ivan, 2007, New mites of the genus Pachyseius Berlese from Bulgaria (Acari: Pachylaelapidae), pp. 59-68 in Zootaxa 1485</i> on pages 64-66, DOI: <a href="http://zenodo.org/record/176951">10.5281/zenodo.176951</a&gt

Carinostoma elegans neu für die Weberknechtfauna der Slowakei (Opiliones, Dyspnoi, Nemastomatidae)

A new genus and species of small harvestman was found for the first time in Slovakia – Carinostoma elegans (Sorensen, 1894). One male and two females were collected in the Mlyňany arboretum of the Slovak Academy of Science (western Slovakia). Descriptions and photographs of both sexes of C. elegans are provided. Additional comments, and a map of distribution of all species of this genus, are provided.Eine neue Weberknechtgattung und –art wurde erstmals in der Slowakischen Republik nachgewiesen – Carinostoma elegans (Sørensen, 1894). Ein Männchen und zwei Weibchen wurden im Mlyňany Arboretum der Slovakischen Akademie der Wissenschaften nachgewiesen. Beide Geschlechter sowie die Verbreitung der Art werden beschrieben und abgebildet

New mites of the genus Pachyseius Berlese from Bulgaria (Acari: Pachylaelapidae)

Mašán, Peter, Mihál, Ivan (2007): New mites of the genus Pachyseius Berlese from Bulgaria (Acari: Pachylaelapidae). Zootaxa 1485: 59-68, DOI: 10.5281/zenodo.17695

Beech bark disease in Slovakia related to fungi of the genus Nectria S.l. and the anatomy of necrotised bark and wood: a brief review

This short review summarises the history and current knowledge regarding beech bark disease (BBD) in Slovakia. Moreover, the results of ongoing long-term disease monitoring are summarised. The article also provides a list of the 29 Nectria s.l. species found to date in Slovakia, complete with information about their occurrence on host tree species. Above all, we highlight the need for histopathological research on beech tissues attacked by different Nectria spp. Notably, neither the defensive response mechanisms of host cellular tissues at the anatomical and biochemical levels nor the strategy of decomposition by different pathogens have been explored in beech

Beech bark necrosis: partition- ing the environmental and spatial variation of the damage severity in Central and South-Eastern Europe

<span style="font-family: Arial,Helvetica,sans-serif; font-size: small;">The beech bark necrosis (BBN) infestation severity of European beech (<em>Fagus sylvatica</em> L.) was assessed in regions of Central (CE) and South-Eastern Europe (SE). Altogether more than 10,000 trees were sampled at 114 sites. Using variation partitioning method, we examined the pure and shared effects of stand, site, climate and spatial sets of variables on mean BBN severity. Our rating included (i) the whole stand, (ii) tree social status classes, (iii) canopy (C) and (iv) understory (U) trees separately. We found that C trees were less affected by BBN than sub-canopy and U trees in both regions. There were found inter-regional differences in amount of explained variability (25.473.9%) for whole stand BBN and in the sensitivity of C and U trees to the environmental gradients. The analysis revealed that the climate and spatial variables followed by stand variables had the largest marginal effects on mean BBN severity in all models, while the site set of variables had the weakest one. More than half of the explained variation was shared among four sets of variables in SE, contrary to CE. Except to U trees in SE, the effect of climate pure or spatially structured remained the highest also after partitioning of variance; more in SE than in CE. Taking into account positive association between mean annual temperature and mean BBN severity in C trees in SE, reinforced negative effect of climate change on the necrosis might be expected to be more serious mainly in low situated beech forests there. Promoting the tree species diversity in forested areas with higher incidence of beech bark necrosis, i.e. in low altitudes in SE, could reduce the susceptibility of forests to the necrosis at regional level in the future. For better understanding of the relative importance of environmental and spatial variables on BBN severity, further research performed on finer spatial scale (extent and grain) is necessary, along with accounting for pathogens involved in the infestation.</span

Investigations of mature Scots pine stands in wind-throw areas in Norway spruce forests in Western Rhodopes

We investigated the current health condition (defoliation), state of natural regeneration, and mycoflora and phytopathogen-caused attacks in Scots pine forests (Pinus sylvestris L.) planted in the 1960s in areas affected by wind disturbances in the West Rhodope Mountains in Bulgaria. Some damage types (resin outflow and anthropogenic damage) were present to a low extent in the research plots (S – Selishte and PK – Pobit Kamak). Some were missing completely (damage by deer and other animals, the presence of lignicolous fungi and abiotic damage). The most important results of this study were the following: i) the occurrence of the bark beetle pest Tomicus minor Hartig (Coleoptera, Scolytinae) was recorded on average in 4.6 (S) and 2.3 (PK) of fallen shoots under the tree crown within 1 m diameter around the stem; ii) significant damage to tree crowns due to the loss of assimilation organs in Scots pine trees (28% – S and 39% – PK, respectively) was several times higher than that recorded in Norway spruce (Picea abies L.) (10%); iii) tree species composition resulting from natural regeneration showed 95–100% proportion of Norway spruce despite the predominance of Scots pine in the maternal stand. These observations might provide evidence of unsuitable environmental conditions in the studied localities for pine forests on the southern range of the natural P. sylvestris occurrence. Forest management in similar ecological and climatic conditions should aim at significant diversification of the forest stand structure by utilizing tree species suitable for the given ecosystems

A Structural Assessment of Sycamore Maple Bark Disintegration by Nectria cinnabarina

Previous phytopathological studies of the fungal pathogen Nectria cinnabarina have been focused on its distribution and host diversity but little is known about the spread of this pathogen and the defence responses of forest trees to an infection inside host tissues. Histopathological alterations of bark, periderm, phloem and woody tissues were investigated in sycamore maple (Acer pseudoplatanus) branches following their natural attack by the advanced anamorph and teleomorph developmental stages of the fungus. Light, fluorescence, confocal laser scanning and scanning electron microscopy techniques supplemented by X-ray micro-computed tomography imaging were used to distinguish between healthy and disintegrated plant tissues. The intercellular spread of fungal hyphae was found primarily in the phelloderm. Expanding hyphae aggregations produced ruptures in the phellem and the disintegration of both phellogen and phellodermal parenchyma cells in close proximity to the expanding fruiting bodies of the fungus. Thicker hyphae of the teleomorph fungal stage heavily disintegrated the phelloderm tissues and also induced enhanced sclerification of the nearby phloem tissues that limited the spread of the infection into the sieve tubes. Both the intercellular and intracellular spread of hyphae inside the peripheral parts of sclereid clusters led to the disintegration of the compound middle lamellae but the hyphae were only rarely able to pass through these structural phloem barriers. The massive fungal colonization of both lumens and disintegrated tangential cell walls of ray parenchyma cells resulted in severe cambial necroses. Although the hyphae penetrated into the outermost annual growth rings of the xylem, no cell wall disintegration of the parenchyma cells, vessels and fibres was revealed. Despite the local cambial necroses and severe phloem ray disintegration, the bark remained attached to the examined branches and no bark cankers were formed