Wood Decay Research Articles

Ratio of Stem Wood Volumes in Forest Stands and Dead Wood of the Taiga Spruce Forests in European Russia

The article discusses the formation of the stem wood volumes ratio between the forest stands and the deadwood in an indigenous forest community with a contribution from wood-decaying fungi, using the spruce formations of the European Russia’s taiga zone as an example. For the analysis, 30 spruce ecosystems were taken, 10 in each of the taiga subzones (northern, middle and southern) with different dynamic characteristics — climax, demutational and digressional ecosystems. Using the method of study plots (SP), the silvicultural characteristics of ecosystems and the morphometric indicators of trees were described, and the volumes of stem wood of the forest stands forming phytocenoses and the deadwood decomposed by wood-destroying fungi were calculated. Indicators of the stem wood volumes ratio between the forest stands and the dead wood in spruce plantations of various dynamic phases were calculated, for which phase position scores were calculated. Indicators of the relationship between the volumes of stem wood in forest stands and in dead wood (R2)and linear correlation coefficients (r) for forest stands of different successional positions were determined in Microsoft Excel. The calculations confirmed the presence of a relationship between the stem wood volumes of tree stands and deadwood for the studied spruce forests using a point estimate of the phase position of ecosystems: in both programs (R2 and r) the relationship indicators were characterized as strong to very strong (Chaddock, 1925).

Oxidative stress and culture atmosphere effects on bioactive compounds and laccase activity in the white rot fungus Phlebia radiata on birch wood substrate

Wood-decaying white rot fungi live in changing environmental conditions and may switch from aerobic to fermentative metabolism under oxygen depletion. Decomposition of wood and lignocellulose by fungi is dependent on enzymatic and oxidative biochemistry including generation of reactive oxygen species. In this study, we subjected semi-solid wood-substrate cultures of the white rot fungus Phlebia radiata to oxidative stress by addition of hydrogen peroxide under aerobic and anaerobic cultivation conditions. Wood decomposition and fungal metabolism were followed by analysis of extracellular organic compounds, mycelial growth, and laccase activity. Under both atmospheric conditions, accumulation of bioactive aromatic compounds from birch wood occurred into the culture supernatants after hydrogen peroxide treatment. The supernatants inhibited both fungal growth and laccase activity. However, the fungus recovered from the oxidative stress quickly in a few days, especially when cultivated under regular aerobic conditions. With repeated hydrogen peroxide treatments, laccase suppressive-recovery effect was observed. Culture supernatants demonstrated antioxidant and antimicrobial effects, in concert with emergence of chlorinated birch-derived organic compounds. Bioactivities in the cultures disappeared in the same pace as the chlorinated compounds were transformed and de-chlorinated by the fungus. Our results indicate tolerance of white rot fungi against excessive oxidative stress and wood-derived, growth-inhibiting and harmful agents.

Reticulate evolution and rapid development of reproductive barriers upon secondary contact in a forest fungus

Reproductive barriers between sister species of the mushroom-forming fungi tend to be stronger in sympatry, leading to speculation on whether they are being reinforced by selection against hybrids. We have used population genomic analyses together with invitro crosses of a global sample of the wood decay fungus Trichaptum abietinum to investigate reproductive barriers within this species complex and the processes that have shaped them. Our phylogeographic analyses show that T.abietinum is delimited into six major genetic groups: one in Asia, two in Europe, and three in North America. The groups present in Europe are interfertile and admixed, whereas our crosses show that the North American groups are reproductively isolated. In Asia, a more complex pattern appears, with partial intersterility between subgroups that likely originated independently and more recently than the reproductive barriers in North America. We found pre-mating barriers in T.abietinum to be moderately correlated with genomic divergence, whereas mean growth reduction of the mated hybrids showed a strong correlation with increasing genomic divergence. Genome-wide association analyses identified candidate genes with programmed cell death annotations, which are known to be involved in intersterility in distantly related fungi, although their link here remains unproven. Our demographic modeling and phylogenetic network analyses fit a scenario where reproductive barriers in Trichaptum abietinum could have been reinforced upon secondary contact between groups that diverged in allopatry during the Pleistocene glacial cycles. Our combination of experimental and genomic approaches demonstrates how T.abietinum is a tractable system for studying speciation mechanisms.

Armillaria Species Causing Kiwifruit Vine Decline and Root Rot in Northeastern Türkiye: A Growing Concern for Kiwifruit Health

ABSTRACTKiwifruit (Actinidia deliciosa) production in northeastern Türkiye is facing an emerging threat from Armillaria root rot. Surveys conducted in August 2021 and 2022 revealed that 10.5%–17.5% of the 200–500 vines within each of 35 kiwifruit orchards in the Perşembe, Gülyalı and Altınordu districts of Ordu province exhibited symptoms of Armillaria root rot, including complete defoliation. Diseased plants exhibited diagnostic signs on their root collars and woody roots, including white mycelial fans, extensive wood rot and rhizomorphs. A single Armillaria isolate was obtained from each of the 35 symptomatic orchards. Molecular identification, employing DNA sequencing of the large subunit (LSU) region of rDNA, the translation elongation factor subunit 1‐alpha (TEF1) gene and the second largest RNA polymerase II B‐subunit (RPB2) gene, identified 20 isolates as Armillaria gallica and 15 as A. mellea. Phylogenetic analyses, based on TEF1 alignments, further supported the species identification with a 100% bootstrap value. To examine genetic diversity, start codon targeted (SCoT) marker 13 was used, successfully differentiating the two Armillaria species and revealing three distinct clades. Clades I and II comprised 15 and 5 isolates of A. gallica, respectively, while Clade III contained all 15 A. mellea isolates. Pathogenicity testing on kiwifruit seedlings (cv. Hayward) revealed the ability of both A. gallica and A. mellea isolates to induce disease. Rhizomorph‐producing isolates in kiwifruit seedlings displayed high virulence, inducing severe leaf necrosis and seedling mortality, while isolates lacking these structures were non‐pathogenic. This study identifies the first global instance of A. gallica causing kiwifruit root rot. This finding, along with the identification of A. mellea as a causal agent in the country, highlights the emerging threat of Armillaria root rot to kiwifruit production in the region.

Ecology and conservation of cavity-nesting birds in the Neotropics: Recent advances, future directions, and contributions to ornithology

ABSTRACT About 35% of tree-cavity-nesting bird species inhabit the Neotropics, a region crucial to understanding their breeding ecology, conservation, and roles in social-ecological systems. Sixteen years ago, Cornelius et al. (2008) reviewed published knowledge and identified research priorities for Neotropical cavity-nesting birds. Advances since 2008 have not been synthesized and many remain excluded from dominant ornithology because of barriers that disproportionately affect people and ideas from the Global South. Here, we review recent advances in knowledge about Neotropical cavity-nesting birds, introduce the Special Feature series “Ecology and conservation of cavity nesters in the Neotropics,” and outline possible directions for future research. Research in the Neotropics has advanced knowledge of breeding biology, demonstrated that nest sites are limited and birds compete for cavities (mainly in humid forests), identified non-excavated cavities (formed by wood decay) as the main source of cavities and demonstrated the importance of understanding Indigenous and local community relationships to birds. With field studies across the Neotropics, the Special Feature series shows how environment, people’s common imaginaries, vegetation management, and behavior of avian excavators can interact to influence cavity availability, with ecological consequences for many cavity-using organisms. In the future, researchers should center ethno-knowledge and natural history to create an accurate list of cavity-nesting birds in the Neotropics, and integrate this knowledge into studies of population and community ecology. It is also important to study factors that influence cavity dynamics, especially using a social-ecological systems framework and especially in arid and semi-arid regions. We recommend expanding the concept of nest webs (ecological networks of cavity nesters) to incorporate additional cavity substrates (e.g., termitaria, cliffs), cavity alternatives (e.g., bulky enclosed stick nests of many Furnariidae), and cavity-using taxa beyond birds and mammals (e.g., social insects, snakes), which abound in the Neotropics but were not contemplated in the original nest web formulation. Translated versions of this article are available in Supplementary Material 1 (Spanish) and Supplementary Material 2 (Portuguese).

Diversity of macrofungi in southeast Xizang 1. The wood-decay fungi

ABSTRACT A survey on the diversity of wood-decay fungi in southeast Xizang was carried out from 2019 to 2023. Based on morphology, ecology, biogeography, and molecular biology, 558 species, belonging to three classes, 15 orders, 57 families, and 177 genera, were identified. One new species, Epithele miscanthi, is described. Species composition analysis showed that there were fifteen dominant families with more than 10 species. These families include 459 species, accounting for 82.26% of the total species found. Thirty-three genera with five or more species are treated as dominant genera, and 325 species were included in these genera, accounting for 58.24% of the total species. Among these, 313 species (56.09%) occurred on angiosperm wood only, 168 species (30.11%) on gymnosperm wood only, 45 species (8.06%) on both angiosperm and gymnosperm wood, 17 species (3.05%) on monocotyledons only, and only one species, Hymenochaete rheicolor, grew on both monocotyledons and dicotyledons. The highest number of species, 266 (47.67%), were found on fallen trunks, followed by fallen branches, rotten wood, stumps, dead standing trees, living trees, and charred wood with 175, 123, 116, 82, 57, and 4 species, respectively. In addition, 456 species cause a white rot and 85 species cause a brown rot, accounting for 81.72% and 15.23% of our studied species, respectively. Statistics were also made on the rotting type and the number of edible or medicinal fungi.

Interaction between peptide and solid lignin suggest mechanisms of abiotic covalent bond formation

The mechanisms behind the formation of soil organic matter (SOM) and associated nitrogen immobilization remain partially elusive, while ongoing research continues to shed light on carbon and nitrogen sequestration in the environment. Studies show that quinone-like structures within alkali-soluble humic extracts of SOM can bond covalently with nitrogen-containing molecules derived from proteinaceous organic matter. However, direct molecular evidence for this chemical bonding with lignin in the solid form and non-solvent-extracted SOM is lacking. Using gel-state 1H-15N heteronuclear single quantum coherence (HSQC) high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy, we demonstrate that a 15N-labeled peptide (glycine-glycine-glycine-arginine, GGGR), can covalently bind to solid, untreated, brown rotted wood as well as 1,2-naphthoquinone, a quinone-model molecule typically found in degraded lignin. The new peaks in both reactions represent a change in the environment surrounding the N-functional groups. Interaction of the 15N-labeled peptide with the model quinone produced NMR cross peaks that are similar to those of the solid lignin. This suggests that the quinone-like structures are the most likely functional groups to form covalent bonds with peptides in the degraded lignin. Both Michael addition and Schiff base formation is proposed when the peptide GGGR interacts with white oak lignin and 1,2-naphthoquinone. These processes are of considerable importance to N incorporation into SOM and offer insights into how proteinaceous molecules could potentially be preserved and sequestered through covalent bond formation.

Occurrence and Characteristics of Serpula himantioides Fruiting Bodies on Living Trees in Japan.

Serpula himantioides is a globally distributed wood decay fungus that causes heartwood decay in several tree species. We investigated the occurrence of S. himantioides fruiting bodies in Japan for two years and six months to characterize their biology. The fruiting bodies matured in autumn and occurred on living Chamaecyparis pisifera, Chamaecyparis obtusa, Larix kaempferi, and Cryptomeria japonica trees, as well as on dead trees and soil. Assessing three circular plots, the incidence of living trees with S. himantioides fruiting bodies was lowest in the plot with the most advanced heartwood decay. Furthermore, fruiting bodies occurred more frequently in the lower slope direction of the trunk. Analysis using the pair correlation function suggested that the spatial distribution pattern of living trees with fruiting bodies may change from intensive to random with heartwood decay progress. Finally, according to generalized linear and generalized linear mixed models, which were used to investigate the factors affecting the development of fruiting bodies in C. pisifera, C. obtusa, and L. kaempferi, no clear relationship was found between the presence or absence of fruiting bodies and heartwood decay. Thus, we suggest that fruiting bodies can occur in healthy living trees as well as in living trees in the early stages of heartwood decay.

Hygrothermal risk assessment tool for brick walls in a changing climate

Due to the heritage value of historical buildings, external facades can often not be modified. Therefore, in heritage buildings interior insulation is often considered when undergoing an energy renovation. However, interior retrofitting drastically changes the hygrothermal behaviour of a wall and can potentially cause moisture-related problems. Besides an interior retrofit, a changing climate might also trigger some of these damage mechanisms as parameters such as temperature and precipitation will change over time. Hygrothermal models can provide relevant insights into the risk of deterioration associated with these damage phenomena. However, these Heat, Air and Moisture (HAM) tools are commercially available but rarely used in the building industry to study deterioration risks. Translating research into practical tools and guidelines is a challenge across the whole field of building renovation. This paper aims to tackle that challenge, by means of creating a hygrothermal risk assessment tool based on 48,384 HAM-simulations for the climate of Brussels, Belgium. Seven different performance criteria are addressed and discussed: freeze-thaw damage, mould growth, wood rot, corrosion, moisture accumulation, salt efflorescence and bio-colonisation. Subsequent to a sensitivity analysis, the study further explains how these results can be translated into practice, providing building practitioners the most suitable insights and recommendations. The development of an interactive web tool to assess hygrothermal risks is demonstrated and its use and benefits are further elaborated.

The complete mitochondrial genome of the basidiomycetous fungus, Tinctoporellus epimiltinus strain RS1

Tinctoporellus epimiltinus is widely known as a wood-decaying fungus. In the present study, we identified the complete mitochondrial genome of this species using next-generation sequencing technology. Our findings revealed that the genomic structure is a circular molecule with a size of 51,878 bp. Consistent with most Basidiomycota species, it consists of 14 core protein-coding genes, one ribosomal protein gene (rps3), 26 transfer RNA genes, and small and large ribosomal RNA (rns and rnl) genes. Seven additional open reading frames were identified. These included two sequences similar to DNA polymerases, an endonuclease-like sequence, and four hypothetical proteins. The mitochondrial genome exhibited a nucleotide composition of A (36.24%), C (12.04%), G (13.18%), and T (38.55%), resulting in a 25.21% GC content. A phylogenetic tree constructed using the combined mitochondrial gene dataset provided insight into the phylogenetic relationships of this species within the context of Basidiomycota and its members.

Evaluation of six phenolic compounds content and antifungal activity against wood-decay fungi of tobacco waste extracts obtained by ultrasound-assisted extraction

The tobacco industry produces substantial amounts of biomass waste that contains bioactive substances that may serve as renewable energy sources. This study reports an efficient and environmentally friendly method for the simultaneous extraction of gallic, protocatechuic, vanillic, chlorogenic, caffeic, and ferulic acids from tobacco waste. The ultrasound-assisted extraction (UAE) parameters were optimized using one-factor-at-a-time method and response surface methodology (RSM), in combination with Box-Behnken design (BBD). The optimal extraction conditions were an extraction temperature of 62 °C, a solvent-to-solid ratio of 19 mL/g, an ethanol-to-water ratio of 62%, and an extraction time of 38 min. The composition and content of phenolic compounds extracted using this optimized method were identified by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole-time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS). The extraction yield and antifungal activity against wood-decay fungi using the extracts obtained with the UAE method were much higher than those obtained using maceration and heat reflux extraction. The results demonstrated that the UAE method extracted six phenolic compounds in tobacco waste, which could then be quantitatively analyzed. This study provides a green and efficient method for extracting active ingredients from waste tobacco and offers a new perspective for utilizing tobacco waste as an antifungal agent against wood-decay fungi.

Molecular phylogeny and morphology reveal a new wood-inhabiting fungal species, Hyphoderma guangdongense (Polyporales, Basidiomycota), from China

Hyphoderma is one of the most important representative groups of wood-inhabiting fungi. These fungi secrete various enzymes capable of degrading cellulose, hemicellulose, and lignin into simple inorganic substances. The taxa within the genus cause the white rot of wood, play a key role in the carbon cycle, and are the most efficient wood decomposers in the forest ecosystem. This study proposes a new wood-inhabiting fungal taxon, Hyphoderma guangdongense, based on morphological features and molecular evidence. It is characterized by the white hymenial surface, a monomitic hyphal system having the generative hyphae with clamp connections, the presence of the septate and tubular cystidia, and cylindrical basidiospores (6–10 × 3–5 µm). The phylogenetic tree inferred from a combination of the internal transcribed spacers (ITS) and large subunit (nrLSU) of the nuclear ribosomal DNA (rDNA) sequences revealed that H. guangdongense placed into the genus Hyphoderma, in which it is closely related to a clade comprising two taxa, H. setigerum, and H. floccosum. A full description, illustrations, and results of the new species' phylogenetic analysis are provided.

The wood-decaying fungal diversity unveiled by morphology and phylogeny in Ailaoshan Mountain, Yunnan, China

Seven field surveys were carried out in the Ailaoshan area of Yunnan Province, China, from 2016 to 2021, in which 2,814 specimens of wood-decaying fungal species were collected and identified based on morphology and phylogenetic analyses. One hundred and three wood-decaying species were identified, belonging to 64 genera, 29 families, and nine orders. Polyporales is the most abundant order in this area, accounting for 55.34% of all species, while Polyporaceae is the most abundant family, accounting for 18.45% of all species discovered in this area. The wood-decaying fungal checklist is provided according to the latest fungi classification system. Of these species, 11 are edible and therapeutic, four are forest pathogens, eight are threatened, and nine have just been reported from Ailaoshan Mountain. These species comprise 10.68%, 3.88%, 7.77%, and 8.74% of all species, respectively, while 71 species, or 68.93%, have unclear functional relationships. The sequences of the Internal Transcribed Spacer (ITS) gene region of the studied specimens were generated, and the phylogenetic analyses were performed with the maximum likelihood, maximum parsimony, and Bayesian inference methods. This study enriches the diversity of wood-decaying fungi in the Ailaoshan area. Also, it provides a theoretical basis for the future protection and utilization of wood-decaying fungal resources in this area.

Wood decay and Norway spruce vulnerability to wind-inflicted mortality in monospecific and mixed stands in hemiboreal forests

Pathogen-caused stem and root decay are becoming increasingly common in Norway spruce (Picea abies (L.) H. Karst) which is believed to contribute to greater stand instability and susceptibility to wind-inflicted damage. Thus, this study aims to assess the effect of root and stem decay on Norway spruce vulnerability to wind-inflicted mortality in monospecific and mixed stands, to widen our base of knowledge on potentially more resilient spruce forest management approaches in hemiboreal forest zone. In this study we used data from: i) the National Forest inventory (NFI), ii) 34 observation plots established in wind-affected stands, iii) two transects (9200 m long, 36.8 ha inspection area combined), iv) and monospecific spruce plantation thinning experiment (five thinning intensities with two repetitions of each) affected by wind. We found that the total mortality of spruce during the NFI four five-year re-measurement cycles (2003–2007, 2008–2012, 2013–2017, 2018–2022) was 2.28 %, during which the main disturbance-causing agents were wind at 0.86 %, pests at 0.41 %, intra/interspecific competition at 0.37 %, and diseases at 0.36 %. NFI data-based multinomial logistic regression model revealed that the probability of wind-inflicted spruce mortality is dictated by soil moisture regime, stand age, stand stocking level, and tree decay presence. Results from the 34 established observation plots show that wood decay is a potential risk factor associated with wind damage occurrence in spruce stands. In a spruce stand, when a group of trees are damaged by wind the proportion of undecayed trees increases. Whereas a single tree is more likely to be attributed to decay caused wind damage.Results point towards deciduous broadleaf admixture having a positive effect on mitigating wind damage among non-decayed spruce trees: however, decayed trees, are more likely to be affected in such stands. The thinning experiment portion of this study suggests that increasingly intensive thinning in monospecific spruce stands will lead to an increasing spread of root and stem decay and thus the risk of wind damage. Therefore, from this perspective, the main goal is to reduce the root and stem decay presence in the stand and thus increase wind stability. We suggest further research to be directed into finding the optimal initial spruce seedlings density with a combination of coniferous and deciduous broadleaf species in order to mitigate root and stem decay presence and wind-inflicted spruce mortality in the forest stands.

The Use of Bacteria, Actinomycetes and Fungi in the Bioprotection of Solanaceous Crops against Tobacco Mosaic Virus (TMV)

Tobacco mosaic virus (TMV) is one of the most persistent and infectious plant viruses. The substantial economic losses caused by TMV in the production of tobacco and vegetables (especially in the Solanaceae family) are prompting the introduction of innovative solutions that effectively inhibit infection by this pathogen. Biological control agents based on bacteria of the genera Pseudomonas, Bacillus, Pantoea and actinomycetes are becoming increasingly popular in the fight against TMV. Some fungi, including Fusarium spp., Trichoderma spp., Alternaria spp. and Sepedonium spp., as well as wood-rotting fungi, also exhibit high anti-TMV activity. This article presents a comprehensive review of recent scientific advances in the bioprotection of selected solanaceous crops against TMV. It provides information on the structure of the virus, its host range, pathogenicity and the severity of losses caused in pepper, tomato and tobacco production. The review characterises environmentally safe techniques involving biological control agents naturally occurring in the environment and the bioactive compounds extracted from them. It also identifies their effects on crops at the morphological, physiological and molecular levels. In addition, the manuscript outlines prospects for the future applications of beneficial micro-organisms and active compounds derived from them in the protection against TMV.

Evaluation of the Potentials of Tobacco Waste Extract as Wood Preservatives against Wood Decay Fungi

Utilizing conventional wood preservatives poses potential risks to ecosystems and human health. Therefore, the wood protection industry must develop alternatives that are both efficient and environmentally friendly. In this paper, industrial tobacco waste extracts were used as eco-friendly wood preservatives against wood decay fungi. Three major constituents in the extracts were identified via gas chromatography-mass spectrometry (GC-MS) and included nicotine, neophytadiene, and 2,7,11-cembratriene-4,6-diol. The antifungal activities of waste tobacco extracts and these three major constituents against wood decay fungi were tested. At a concentration of 40 mg/mL, the tobacco waste extract treated with 50% ethanol significantly inhibited the activity of wood decay fungi. This was because the extract contained nicotine as the primary active component and neophytadiene as a synergistic active component. Wood decay resistance tests were conducted on Pinus yunnanensis and Hevea brasiliensis treated with a 50% ethanol extract of tobacco waste at a concentration of 40 mg/mL. The mass losses of Pinus yunnanensis exposed to G. trabeum and T. versicolor were 4.11% and 5.03%, respectively, while the mass losses in Hevea brasiliensis exposed to G. trabeum and T. versicolor were 7.85% and 9.85%, respectively, which were classified as highly resistant. The acute ecotoxicity of the tobacco waste extract was assessed using a kinetic luminescent bacteria test with Aliivibrio fischeri, which revealed significantly lower acute toxicity than a commercial copper-based wood preservative. This study offers insights into high-value utilization of tobacco waste and advancement of natural wood preservatives.

Evidence of Cooperative Interactions between Rhizobacteria and Wood-Decaying Fungi and Their Effects on Maize Germination and Growth

Advances in soil microbial communities are driving agricultural practices towards ecological sustainability and productivity, with engineering microbial communities significantly contributing to sustainable agriculture. This study explored the combined effects of two white-rot fungi (Trametes sp. and Pleurotus sp.) and six rhizobacterial strains belonging to four genera (Acinetobacter sp., Enterobacter sp., Flavobacterium sp., and Pseudomonas sp.) on maize growth and soil enzymatic activity over a 14-day period. At the plant level, germination, fresh and dry mass of the aerial and root parts, length, and stage of development of the stem, as well as the chlorophyll content, were evaluated. Furthermore, soil dehydrogenase, acid and alkaline phosphatases, pH, and electrical conductivity were evaluated. Rot fungi induced distinct effects on maize germination, with Pleurotus sp. strongly suppressing maize germination by 40% relative to that of the control. The isolated bacterial strains, except Enterobacter sp. O8, and 8 of the 12 fungus + bacterial strain combinations induced germination rates higher than those of the control (≥40%). Combinations of Flavobacterium sp. I57 and Pseudomonas sp. O81 with the rot fungus Pleurotus sp. significantly improved plant shoot length (from 28.0 to 37.0 cm) and developmental stage (fourth leaf length increase from 10.0 to 16.8 cm), respectively, compared with the same bacteria alone or in combination with the rot fungus Trametes sp. In the soil, the presence of both fungi appeared to stabilize phosphatase activity compared to their activity when only bacteria were present, while also promoting overall dehydrogenase enzymatic activity in the soil. Integrating all parameters, Trametes sp. rot fungus + Enterobacter sp. O8 may be a potential combination to be explored in the context of agricultural production, and future studies should focus on the consistency of this combination’s performance over time and its effectiveness in the field.

Butylated hydroxytoluene and ethylenediaminetetraacetic acid combined with cedarwood oil as wood treatments for protection from subterranean termites and wood-decaying fungi

Butylated hydroxytoluene and ethylenediaminetetraacetic acid combined with cedarwood oil as wood treatments for protection from subterranean termites and wood-decaying fungi

Electrical integrity and week-long oscillation in fungal mycelia

The electrical potential of the mycelia of a cord-forming wood decay fungus, Pholiota brunnescens, was monitored for over 100 days on a plain agar plate during the colonization onto a wood bait. Causality analyses of the electrical potential at different locations of the mycelium revealed a clear and stable causal relationship with the directional flow of the electrical potential from the hyphae at the bait location to other parts of the mycelium. However, this causality disappeared after 60 days of incubation, coinciding with the onset of slow electrical oscillation at the bait location, which occurred over one week per oscillation cycle. We speculated that the hyphae that initially colonized the bait may act as a temporary activity center, which generates electrical signals to other parts of the mycelium, thereby facilitating the colonization of the entire mycelial body to the bait. The week-long electrical oscillation represents the longest oscillation period ever recorded in fungi and warrants further investigation to elucidate its function and stability in response to environmental stimuli.

Commodity risk assessment of maple veneer sheets from Canada.

The European Commission requested the EFSA Panel on Plant Health to deliver a risk assessment on the likelihood of pest freedom from Union quarantine pests and pests subject to measures adopted pursuant to Article 30 of Regulation (EU) No 2016/2031 for the maple veneer sheets manufactured according to the process set out by Canada, with emphasis on the freedom from Davidsoniella virescens and Phytophthora ramorum (non-EU isolates). The assessment was conducted for veneer sheets of up to 0.7 mm and up to 6 mm thickness, taking into account the different phases in the veneer production in a systems approach. Some of those phases, taken alone, including the heat treatment of logs in a water bath, the cutting into thin veneer sheets and the final high heat drying of veneer sheets are expected to be effective against some of the pests, without uncertainties, making the system approach fully effective. The panel considers that no insects would survive cutting of logs into thin veneer sheets of 0.7 mm and that Xylella fastidiosa will not survive the temperatures in the water bath and final drying of veneers. The degree of pest freedom for the different groups of organisms is generally very high with slightly lower degree of pest freedom for veneer sheets of 6 mm thickness because of lower temperatures reached in the final drying of veneer sheets compared to thinner sheets. P. ramorum is not expected to survive the high heat drying of thin veneer sheets, but it may survive the lower temperatures inside thicker veneer sheets. The Expert Knowledge Elicitation (EKE) indicated, with 95% certainty, that between 9989 and 10,000 veneer sheets (thickness 6 mm) per 10,000 will be free from living P. ramorum. For D. virescens, the EKE indicated, with 95% certainty, that between 9984 and 10,000 veneer sheets (0.7 mm) per 10,000 and that between 9954 and 10,000 veneer sheets (6 mm) per 10,000 will be free from living inoculum. For other relevant groups of pests, the greatest likelihood of pest presence was observed for wood decay fungi. The EKE indicated, with 95% certainty, that between 9967 and 10,000 veneer sheets (0.7 mm) per 10,000 and that between 9911 and 10,000 veneer sheets (6 mm) per 10,000 will be free from living wood decay fungi.