Bursaphelenchus taphrorychi sp. n. is described from the bark of European beech, Fagus sylvatica. All propagative stages of the nematode are numerous in larval galleries of the beech bark beetle, ...Taphrorychus bicolor, while dauer juveniles are transmitted to new breeding trees under the elytra of adult beetles. The new species is characterised by the body length of 782 (717-858) μm in female and 638 (475-789) μm in male, moderately slender body (a = 35.0 (31.7-36.5) and 35.5 (31.4-37.1) in female and male, respectively), spicules 12.0-16.0 μm long, lateral fields with four incisures (i.e., three bands), and the arrangement of the seven male caudal papillae (i.e., a single precloacal ventromedian papilla (P1), one pair of adcloacal ventrosublateral papillae (P2), one postcloacal pair (P3) located at ca 60% of the tail length, posterior to the cloacal aperture, and one pair (P4) of subventral papillae of a similar size as the previous pair, but with somewhat sunken tips, located near base of bursa). In the number and arrangement of caudal papillae, stout and curved spicules with prominent rostrum and condylus, small vulval flap, body narrowed posterior to vulva, four incisures in the lateral fields, and long post-uterine sac, B. taphrorychi sp. n. shares most of the key morphological characters with members of the sexdentati-group. However, the newly described species is unique amongst Bursaphelenchus species of this group by the combination of shape of female tail, shape of spicules, and some other morphometric characters. The close relation of B. taphrorychi sp. n. with members of the sexdentati-group has been confirmed by DNA sequencing and phylogenetic analysis of the 28S rDNA region. The taxonomic separation of the new species is also confirmed by the unique molecular profile of the ITS region (ITS-RFLP). In laboratory rearing, B. taphrorychi sp. n. can develop and reproduce on Botrytis cinerea cultures.
The beech leaf‐mining weevil, Orchestes fagi L. (Curculionidae: Curculioninae: Rhamphini), a pest of European beech, Fagus sylvatica L. (Fagaceae), was recently discovered infesting American beech, ...Fagus grandifolia Ehrh., in Nova Scotia, Canada. Adult O. fagi feed on both young and mature leaves of beech as well as on other species (e.g., raspberry, Rubus spp.), but oviposition and larval feeding are restricted to beech. Females oviposit in young developing beech leaves at the time of bud burst. We characterized volatiles emitted from buds, leaves, and sapwood of American beech and examined their potential as attractants alone or when combined with other weevil pheromones for O. fagi. We predicted that adults would be attracted to volatiles emitted from beech leaves, especially those emitted from bursting beech buds. Gas chromatography/mass spectrometry (GC/MS) analyses of volatiles collected from buds at pre‐ and post‐budburst identified two diterpene hydrocarbons, 9‐geranyl‐p‐cymene (1) and 9‐geranyl‐α‐terpinene (2a), that were emitted in large amounts at the time of bud burst. Compound 1 significantly increased mean catch of males and total O. fagi (but not females) on sticky traps compared with unbaited controls. Y‐tube bioassays confirmed attraction of male O. fagi to bursting beech buds and compound 1. Attraction of male O. fagi to 1, emitted in large quantities from American beech, is likely adaptive because both oviposition and mating of O. fagi coincide with budburst. Our data suggest that traps baited with 1 may be useful for monitoring the spread of O. fagi in North America.
The fungus Pseudodidymella fagi is spreading in Europe and causing leaf blotch of European beech, Fagus sylvatica. Between 2008 and 2017, outbreaks of P. fagi were observed on European beech in ...Switzerland, Germany (also on F. orientalis), Austria, and Slovakia. In Slovenia, leaf blotch symptoms were first observed on F. sylvatica in 2018. P. fagi was identified as the causal agent of the observed symptoms in Slovenia by morphological examinations together with sequencing of the internal transcribed spacer (ITS) region of the rDNA. This study links the fungus to the expansion of the known distribution of the disease to Slovenia, and based on in vitro pathogenicity trials, also to a new potential host, Quercus petraea. The pathogenicity tests confirmed F. sylvatica and F. orientalis as hosts for P. fagi, but not Castanea sativa, where pathogenicity to F. orientalis was proved for first time in vitro. Although Koch’s postulates could not be proven for C. sativa, it seems to be partially susceptible in vitro because some of the inoculation points developed lesions. Additionally, damage to Carpinus betulus related to P. fagi near heavily infected beech trees was observed in vivo but was not tested in laboratory trials. Based on the results and our observations in the field, it is likely that P. fagi has a wider host range than previously thought and that we might be witnessing host switching.
Volatile organic compounds (VOCs) have been the focus of interest to understand atmospheric processes and their consequences in formation of ozone or aerosol particles; therefore, VOCs contribute to ...climate change. In this study, biogenic VOCs (BVOCs) emitted from
Fagus sylvatica L. trees were measured in a dynamic enclosure system. In total 18 compounds were identified: 11 monoterpenes (MT), an oxygenated MT, a homoterpene (C
14H
18), 3 sesquiterpenes (SQT), isoprene and methyl salicylate. The frequency distribution of the compounds was tested to determine a relation with the presence of the aphid
Phyllaphis fagi L. It was found that linalool, (E)-β-ocimene, α-farnesene and a homoterpene identified as (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), were present in significantly more samples when infection was present on the trees. The observed emission spectrum from
F. sylvatica L. shifted from MT to linalool, α-farnesene, (E)-β-ocimene and DMNT due to the aphid infection. Sabinene was quantitatively the most prevalent compound in both, non-infected and infected samples. In the presence of aphids α-farnesene and linalool became the second and third most important BVOC emitted. According to our investigation, the emission fingerprint is expected to be more complex than commonly presumed.
Bursaphelenchus piceae
sp. n. is described from the bark of Norway spruce,
Picea abies
. Adults and propagative juveniles of the nematode are found in larval galleries of the six-toothed spruce bark ...beetle,
Pityogenes chalcographus
, while its dauer juveniles aggregate in Malpighian tubules of older larvae, pupae and adult beetles. The new species is characterised by the body length of 719 (530-945) μm in female and 632 (474-808) μm in male, its moderately slender body (a = 41.4 (35.4-50.2) and 42.6 (35.1-47.2) in female and male, respectively), and small spicules (16.0 (14.0-18.3) μm along arc and 13.7 (12.2-15.5) μm along chord). The extended anterior vulval lip in female, lateral fields with four incisures, long post-uterine sac extending for 67-91% of vulva-anus distance, and number (7) and arrangement of male caudal papillae suggest that
B. piceae
sp. n. is closely related to the
xylophilus
-group yet it differs by the relatively small, claw-like spicules with no cucullus at the tip. The close relation of
B. piceae
sp. n. to the
xylophilus
-group has been confirmed by DNA sequencing and phylogenetic analysis. Morphologically
B. piceae
sp. n. most closely resembles
B. tokyoensis
and
B. fagi
but can be separated from both by the unique shape of the spicules. The taxonomic separation of the new species is also confirmed by the unique molecular profile of the ITS region (ITS-RFLP). The presence of dauer juveniles of
B. piceae
sp. n. in Malpighian tubules of adult
P. chalcographus
may lead to extensive damage to this organ as shown by local expansion of the tubule basement membrane and degradation of its cellular epithelium. Detailed phylogenetic analysis revealed that
B. piceae
sp. n. together with five other bark beetle-associated
Bursaphelenchus
species, namely
B. trypophloei
,
B. masseyi
,
B. tiliae
,
B. tokyoensis
and
B. fagi
, constitutes a small phylogenetic clade that is most closely located to, but separate from, the
xylophilus
-group.
Bursaphelenchus tiliae sp. n. is described from the bark of dead branches of the small-leaved lime, Tilia cordata, infested with the lime bark beetle, Ernoporus tiliae. The nematode adults and ...propagative juveniles were present in larval galleries, while dispersal dauer juveniles colonised the Malpighian tubules of adult beetles. Bursaphelenchus tiliae sp. n. is characterised by the body length of 664 (568-817) μm in female and 622 (515-754) μm in male, moderately slender body (a = 41.0 (34.7-47.9) and 43.1 (37.8-51.9) in female and male, respectively), and spicules 20.0 (18.1-21.8) μm long. The extended anterior vulval lip in female, lateral fields with four incisures, long post-uterine sac, and number (7) and arrangement of male caudal papillae, may indicate that B. tiliae sp. n. is closely related to the xylophilus group. It differs from this group by smaller, arcuate spicules with relatively short rostrum, narrow capitulum (5.2-6.9 μm), and indistinct condylus in an almost continuous line with dorsal lamina. Distal third of spicule dorsal contour is usually almost straight. The spicules have a distinct, disk-like cucullus at the terminus. The status of the new species is confirmed by the unique molecular profile of the ITS region (ITS-RFLP) and its close relation to the xylophilus group by DNA sequencing and phylogenetic analysis of the 28S rDNA region. The presence of B. tiliae sp. n. dauer juveniles in Malpighian tubules of their vector bark beetle, E. tiliae, caused limited pathogenicity expressed as a local expansion of the tubule basement membrane and partial degradation of the cellular epithelium.
This study investigated the influence of forest edges on the leaf galls induced by Mikiola fagi (Hartig) on oriental beech (Fagus orientalis Lipsky). Two main objectives of this study were a) to ...compare the effects of forest edges on the number of leaf galls, and b) to compare the forest edges and forest interiors concerning the length and weight of the galls. Investigations on this subject were conducted in 2013-2014 in the Forest Enterprise Chief of Tezcan in Kastamonu located in Western Blacksea region of Turkey. The results showed that 1) the number of leaf galls was greater along the forest edges than in the forest interiors, 2) the length and the weight of the galls did not differ significantly between forest edges and forest interiors.
Fungal endophyte assemblages in leaves of Japanese beech (
Fagus crenata
Blume) trees were investigated in pure beech stands at four localities with different summer temperatures covering the natural ...distribution range of the species.
Ascochyta fagi
Woronich was dominant at every site, and the infection density (ID) of this fungus was higher at sites with low maximum air temperatures. The growth rate of A. fagi on potato dextrose agar was inhibited by temperatures above 30 °C. These results suggest that the population density of A. fagi on Japanese beech leaves is influenced by summer temperatures. However, the number of species and Shannon index of diversity (H′) of endophytic fungi increased with increasing air temperature and a negative correlation was observed between the ID of A. fagi and the diversity of other endophytes. The species composition of minor endophytes was site-specific and may reflect geographic and genetic distances between beech stands.
The main aim of this study was to investigate and compare the patterns of male courtship behaviour in Hipparchia fagi (Woodland Grayling) and H. hermione genava (Rock Grayling) in order to determine ...if premating barriers are involved in the reproductive isolation between the two sympatric and syntopic species.Although they show a similar pattern of sexual behaviour (perching, flight pursuit, courtship), there were significant quantitative inter-specific differences in the step Bowing. During this step, the male bashes and strokes the female antennae between his forewings on the androconial scales revealing the importance of scent stimuli in mate communication. Moreover, different signals, spanning several sensory modalities (visual, chemical, tactile stimuli) and spatio-temporal scales (during the pair flight and the courtship step), might serve as premating barriers between the two species. In particular, both males and females of H. fagi (a woodland habitat specialist) seem to take less time in recognising their conspecific partner, while H. hermione males need to spend more time in courting (and identifying) the “right” females.
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