Interaction between Epicoccum purpurascens and xylophagous basidiomycetes on wood blocks

Epicoccum purpurascens, a component of the bark micromycota, was evaluated as a potential biocontrol agent for three decay‐causing hymenomycetes frequently found in Buenos Aires city trees, Ganoderma platense, Inonotus rickii and Rigidoporus ulmarius. Treatments consisted of dual cultures of E. purpurascens and xylophagous fungi on box elder (Acer negundo) wood blocks. Two inoculation sequences were tested: (i) the biocontrol agent as the first microorganism inoculated followed by the pathogen; and (ii) the xylophagous fungus as the first microorganism inoculated followed by the biocontrol agent. After 3 months of incubation, percentage dry weight loss was calculated. When E. purpurascens was allowed to colonize wood blocks before the introduction of the xylophagous fungus, dry weight loss was significantly reduced in all instances. However, as a secondary colonizer, E. purpurascens mildly reduced the weight loss caused by G. platense, had no effect on degradation by I. rickii and increased wood weight loss by R. ulmarius.     

Scale insects,decay and canker fungi in American beech

Tripartite interactions among phytophagous insects, pathogens and their host plants provide insight into the role of host physiology in determining susceptibility to attack. American beech (Fagus grandifolia) often is simultaneously attacked by beech scale (Cryptococcus fagisuga), one or more Neonectria pathogens and Xylococculus betulae that can result in beech bark disease (BBD). Additionally, beech is frequently infected by heartrot‐decay fungi. Cursory observations in 2011 suggested that beech scale and Neonectria lesion densities were lower and greater, respectively, on trees with decay. In 2012, digital image analysis was used to quantify densities of these organisms on 123 beech from the Adirondack region of New York. Three groups of study trees (n = 41) were used: Inonotus glomeratus‐infected, Phellinus igniarius‐infected and non‐decay trees. Trees infected by decay pathogens supported lower densities of beech scale and higher densities of Neonectria. Densities of X. betulae did not significantly vary among decay groups. These results may be explained by decay‐induced changes in host physiology. Additional work is needed to elucidate the potential role of host bark chemistry in the BBD complex.     

Eutypella canker of maple: first report from Germany and situation in Austria

Eutypella canker of maple, caused by Eutypella parasitica (which is native to North America), is reported for the first time from Germany. From 2013 to 2015, this perennial canker disease was recorded on 105 maple trees in Munich. Six maple species were affected: Acer pseudoplatanus, A. campestre, A. platanoides, A. cappadocicum, A. heldreichii ssp. trautvetteri and A. hyrcanum. Occurrence on the latter three species represents new host records for E. parasitica. In Austria, Eutypella canker was newly discovered on two trees at a second locality in 2011, and it is now known to occur on seven A. pseudoplatanus trees at two localities, which are separated nearly 150 km. A. pseudoplatanus was the most frequent host of E. parasitica in Munich and Austria, which is in agreement with previous studies in Europe. The identity of the causative pathogen as E. parasitica was verified by ITS rDNA sequencing of fungal cultures obtained from cankers in Munich and at both Austrian localities. The presence of large and old cankers in both countries suggests that introduction of E. parasitica dates back a long time, probably several decades. The new records of Eutypella canker in Germany and Austria show that the disease is more widely distributed in central Europe than previously recognized.     

Decay and canker caused by Inonotus rickii spreading on more urban tree species

Inonotus rickii was detected for the first time causing cankers and decay in Acer negundo and Celtis australis in Italy. In a boxelder boulevard, declining trees showed sparse foliage, exudations and cracks in the bark; in some cases, chlamydospore masses were present. Five isolates were collected and compared by growth tests in vitro and electrophoretic analyses; three isolates from the same boulevard showed very similar physiological characters. The increasing importance of the pathogen in urban areas is underlined and discussed.     

Occurrence and decay patterns of common wood‐decay fungi in hazardous trees felled in the Helsinki City

To improve the management of ageing urban trees, the role of wood‐decay fungi as potential causes of stem breakage was investigated among hazardous trees removed in the Helsinki City area during 2001–2004. The study material comprised 194 trees, and included 76 Tilia spp. trees, 58 Betula spp. and 60 Acer spp. Thirteen species or genera of commonly occurring decay fungi were identified on the basis of fruiting bodies and pure cultures. The occurrence of the fungi was investigated in terms of frequency, visibility and as potential causes for stem breakage. Most hazardous fungi caused extensive horizontal decay in the stem; such fungi were Ganoderma lipsiense on Tilia and Acer, Phellinus igniarius on Acer, Inonotus obliquus and Cerrena unicolor on Betula and Kretzschmaria deusta on Acer, Tilia and Betula. Typically, Rigidoporus populinus was frequently present in weak fork formations on Acer trees. Agaric fungi (Pholiota, Armillaria, Pleurotus and Hypholoma) were frequently recorded but were of minor importance from the point of view of tree breakage hazard.     

Individual-scale responses of five dominant tree species to single-tree selection harvesting in a mixed forest in Hokkaido, northern Japan

We investigated the individual-scale responses of five dominant species (Abies sachalinensis, Acer mono, Tilia japonica, Quercus crispula, and Betula ermanii) to single-tree selection harvesting in a conifer–broadleaved mixed forest in Hokkaido, northern Japan. Using data from stems with a diameter at breast height of ≥12.5 cm, collected during 20 years of monitoring a 6.7-ha stand, we analyzed the effects of harvesting in the neighborhood on tree recruitment and the growth (diameter class transition) and mortality of the residual trees. The effects of harvesting varied considerably among tree sizes and species. Harvesting improved the recruitment of A. mono and B. ermanii, and moderated the negative effect of the initial basal area of the surrounding canopy trees on the recruitment of Q. crispula. Conversely, harvesting limited the recruitment of A. sachalinensis by offsetting the positive effect of the initial basal area of the surrounding canopy trees. The growth of A. sachalinensis and Q. crispula decreased with the initial basal area of the surrounding canopy trees. Harvesting in the neighborhood resulted in an improvement in the growth of the trees of these species only in the smaller size classes. With increasing local harvesting intensity, the mortality of smaller A. sachalinensis trees decreased, whereas the mortality of larger trees increased. These results suggest that differences in the local harvesting intensity, spatial patterns of harvesting, and initial stand structures influence the stand-scale dynamics in response to partial harvesting in the mixed forests of this region.     

Occurrence of the wattle wilt pathogen,Ceratocystis albifundus on native South African trees

Ceratocystis albifundus causes the disease known as wattle wilt of non‐native Acacia mearnsii trees in South Africa, Uganda and Kenya. Infection results in rapid wilt and death of susceptible trees and stem cankers on more tolerant trees. It has been suggested that C. albifundus is indigenous to southern Africa, possibly having spread from native Protea spp. to non‐native A. mearnsii and A. decurrens trees. Although C. albifundus has been collected from Protea spp., these reports are based on limited records for which only aged herbarium specimens exist. During surveys of wound‐infecting fungi on native tree species in South Africa, a fungus resembling C. albifundus was collected from Protea gaguedi, Acacia caffra, Burkea africana, Combretum molle, C. zeyheri, Faurea saligna, Ochna pulchra, Ozoroa paniculosa and Terminalia sericea. The identity of the fungus was confirmed as C. albifundus, using comparisons of DNA sequence data for the ITS and 5.8S gene of the rRNA operon. In pathogenicity trials, lesions were produced on C. molle and A. caffra, with some trees beginning to die at the termination of the experiment. This study represents the first report of C. albifundus from native tree species in South Africa and provides unequivocal evidence that the fungus occurs naturally on native Protea spp. The wide host range of C. albifundus, as well as its abundance on these indigenous hosts lends further support to the view that it is a native African pathogen.     

Quantifying relationships between root rot in a white spruce plantation and sporophores of Inonotus tomentosus

The relationship between the occurrence of sporophores of the root rot pathogen Inonotus tomentosus (Basidiomycota, Hymenochaetaceae) and disease symptoms was studied in a white spruce plantation (Picea glauca) in Canada over a period of 14 years. Numbers of sporophore clusters (three or more sporophores within 1 m of each other) were well correlated with numbers of infected living or dead trees (r = 0.64–0.86, p = 0.000–0.003). Infected trees may have sporophores around them before external symptoms of disease occur on the tree. As numbers of dead trees increased, the numbers of infected living trees remained constant, indicating increased infection within the stand. However, the number of sporophores varied considerably between the years. The diagnostic value of sporophores for tomentosus root rot is discussed.     

Differential host residence of adult cryptomeria bark borer,Semanotus japonicus Lacordaire (Coleoptera: Cerambycidae), in relation to tree size of Japanese cedar,Cryptomeria japonica D. Don

To understand factors involved in tree-size dependent vulnerability ofCryptomeria japonica to damage bySemanotus japonicus, residence of adultSemanotus japonicus on host trees was assessed in twoCryptomeria japonica stands, using band trap method and mark-recapture techniques. Adult capture distributions among trees were analyzed in relation to diameter size of each tree. Female adults consistently exhibited more frequent residence on larger trees, under different field conditions. Females that made inter-tree movements preferentially chose larger trees as their destinations. Frequent residence by females on large trees was associated with high productivity of progeny adults. Male adults were also more frequently resident on larger trees. These results suggest that tree-size dependent oviposition accounts for the tree-size dependent vulnerability ofCryptomeria japonica to damage bySemanotus japonicus. Possible causes underlying the differential host residence of adultSemanotus japonicus are discussed.     

Fungi associated with Ips typographus on Picea abies in southern Poland and their succession into the phloem and sapwood of beetle‐infested trees and logs

This study dealt with the species distribution and frequency of fungi associated with the bark beetle Ips typographus (Scolytidae) on spruce trees of various states of health in southern Poland. The spruce trees were assessed by their degree of defoliation and damage of their crowns and trunks after attack by I. typographus. The state of health of trees from which samples were obtained was related to varying stages of brood development of I. typographus. Fungi were isolated from phloem taken from and around insect galleries and the sapwood underneath brood systems. Samples were taken from ‘healthy‐looking’, weakened, wind‐fallen and wind‐broken trees as well as from trap trees. The mycobiota associated with I. typographus was quite diverse in respect of the number of detected species, 65 fungal taxa were obtained from the phloem of trees infested by I. typographus, and 36 taxa occurred in the sapwood underneath insect galleries. The spectrum of fungi mainly consisted of ascomycetes and anamorphic fungi. The ophiostomatoid fungi were represented by 14 species and were the most numerously represented group in all niches examined. The most frequent ophiostomatoid species were Ceratocystis polonica, Ophiostoma ainoae, O. bicolor, O. penicillatum, O. piceae and O. piceaperdum. The frequency of occurrence of ophiostomatoid fungi differed significantly between the phloem and sapwood as well as in relation to the varying states of health of the spruce trees. These quantitative differences in the mycobiota of I. typographus between spruce trees belonging to different health categories can be explained by successional patterns of fungal colonization of host tissues following attack by I. typographus. The pathogenic species C. polonica was the primary invader, occurring most frequently in the sapwood of ‘healthy‐looking’ trees. Ophiostoma bicolor, O. penicillatum and O. piceaperdum also occurred during the early stages of brood development of I. typographus on ‘healthy‐looking’ trees, but they mainly colonized the phloem. In contrast, O. ainoae, O. minuta and O. piceae likely follow the aforementioned species as secondary and tertiary invaders into the phloem and the sapwood of spruce trees.     

Effects of flooding on the recruitment, damage and mortality of riparian tree species: A field and simulation study on the Rhine floodplain

The extensive flooding by the river Rhine on May 12 1999 provided an opportunity to investigate the impact of such an extreme event in terms of damage and mortality of adult trees in floodplains. Such data is highly valuable for determining the potential impact of climate change on the zonation of tree species along rivers. We analysed an extensive dataset of the damage and mortality suffered by groups of adult trees of the following species as a consequence of this flood: the hardwoods Acer campestre L., Acer platanoides L., Acer pseudoplatanus L., Alnus glutinosa (L.) Gaertn., Carpinus betulus L., Fagus sylvatica L., Fraxinus excelsior L., Juglans nigra L., Prunus avium (L.) L., Quercus robur L., Tilia cordata Mill., Ulmus laevis Pall. and Ulmus minor Miller, and the softwoods Salix spp. L. and Populus spp. L.A logistic survivorship curve revealed that mortality of A. platanoides, A. pseudoplatanus and T. cordata increased significantly with increasing duration of flooding; C. betulus and F. excelsior showed a significant increase of damage and mortality with increasing flooding depth. There was no mortality of Salix spp. and Populus spp. in either the flooded or unflooded areas. No statistically significant relationships were found for the other tree species. Multivariate analysis revealed that flooding duration, flooding depth and flooding velocity explain 19%, 11% and 8%, respectively, of the variation in damage and mortality of trees.The survivorship curves of adult trees obtained in this study were combined with similar curves of saplings based on an earlier study and applied in an individual-tree, process-based simulation model. The simulated effects of flooding on an initial random distribution of trees species on a hypothetical floodplain resulted in a realistic zonation of tree species along the river. When extreme events were simulated, the zonation shifted upward. This demonstrates the model's usefulness in assessment and planning studies of the impacts of climate change on tree species composition in river floodplains in north-west Europe.     

Effects of altitudinal gradient on species composition of naturally regenerated trees in <Emphasis Type="Italic">Larix kaempferi</Emphasis> plantations in central Japan

Species composition and community structure of naturally regenerated trees in Larix kaempferi plantations and natural forests were compared in relation to altitudinal gradient. Fifty-nine L. kaempferi plantations and 26 natural forest stands including old-growth and secondary forests were selected from 1300 to 2000 m a.s.l. in Mt Kushigata of central Japan. Vegetation plots (10 × 10 m) were established in each stand (85 plots in total). Species composition differed significantly between forest types, particularly on high altitude plots. Some species were significantly biased to natural forests, while no species were biased to plantations. Although some species that responded significantly to altitude were common to both forest types (e.g., Acer ukurunduese, Castanea crenata, and Fraxinus lanuginose f. serrata), some differed between forest types (e.g., Fagus japonica, Prunus maximowiczii, and P. nipponica). Thus, plantation management altered species responses to altitude. Altitude should be considered when planning and carrying out forest ecological restoration in plantations, because species composition of naturally regenerated trees has already been changed by past plantation management. In particular, attention should be paid to ecological restoration at high altitude.     

Occurrence of brown root rot in Ocean Expo Park,Okinawa, Japan: Infection route and preventive control measures

Ocean Expo Park, established in 1976 on subtropical Okinawa Island, Japan, has approximately 8000 planted or naturally grown trees in an area of 77.2 ha. Windfall of these trees occurs mainly due to typhoons; wood chips made from the trunks and roots of windfall trees are commonly used as mulching material throughout the park areas, despite possible infection by pathogenic fungi such as Phellinus noxius, the pathogen causing brown root rot. P. noxius is distributed in tropical and subtropical areas worldwide and has a broad host range. The fungus can infect host plants with mycelia via root-to-root contact or with basidiospores. Here, we report the current status of tree damage caused by brown root rot in the park and infer the infection routes of P. noxius based on microsatellite markers. Among a total of 294 trees surveyed in the park, P. noxius was isolated from 13 trees of five species. P. noxius was observed more frequently on Ficus microcarpa than on other tree species. Ficus superba var. japonica was identified as a new host species, and Bombax ceiba was first recorded as a host plant of P. noxius in Japan. Among the 13 P. noxius isolates from the diseased trees, 2 isolates from adjacent diseased trees were considered to be of the same genet, while the other 11 isolates were different genets, indicating that infection by basidiospores occurred frequently among trees in the entire park, although spread via root systems also occurred between at least two adjacent trees. An identical genet was not detected at distant locations, which suggests that the disease does not spread via chips. However, mulching with chips can lead to wood decay due to decaying fungi other than P. noxius. Therefore, in accordance with the precautionary principle, the park currently prohibits the chipping and mulching of windfall or damaged trees and is considering disposal methods such as burning.     

Treatment of wounds on Acer rubrum with Trichoderma viride1

Wounds on 90 Acer rubrum trees were inoculated with Trichoderma viride in July and August 1973 to determine the effect of the fungus on the development of decay. The trees were 45 years old and 15 cm diam at 1.4 m aboveground. Each tree had 12 wounds, 1.4 cm in diam and 5 cm deep. After a year 28 trees were harvested and isolations were made from the discolored, and decayed wood associated with each wound. Trichoderma viride was reisolated from all wounds that were inoculated with it. Hymenomycetes were isolated frequently from decayed wood associated with wounds not inoculated with T. viride. No Hymenomycetes were isolated from wounds inoculated with T. viride.     

A preliminary report on decay and canker of Acacia richii caused by Inonotus rickii in China

An epidemic wood‐decaying fungus, Inonotus rickii, originating from South America, has spread to the Mediterranean area and southern China. We report the first observation of this fungus on Acacia richii in Panzhihua, southern China. It causes serious canker and decay on urban trees in the investigated area. In addition, phylogenetic analysis showed that the fungus from Panzhihua is closely related to isolates from Europe, South America, Mianyang and Hainan of China. Moreover, it was concluded that the isolates of the species previously reported from the USA do not belong to I. rickii.     

Harmfulness of eriophyid mites (Eriophyoidea,Acari) causing galls on trees and shrubs in the Czech Republic

Fifteen eriophyid mite species are the most abundant species in the Czech Republic from which four, viz.Eriophyes fraxinivorus onFraxinus excelsior, E. platanoideus onAcer platanoides, Phytoptus pyri onPyrus communis andStenacis triradiatus on various species ofSalix injure their host plants and are evaluated as pests. The weight of the leaves attacked by eriophyid mites increase with increasing number of galls pro leaf but the surface of attacked leaves decrease with increasing attack. Harmfulness of eriophyid mites manifests by reducing of assimilation processes, retardation of growth, precocious drying and fall-off of attacked leaves. Heavily attacked young shrubs and trees may dry and decease.With one figure and 2 tables     

Differences in leafminer (Phyllonorycter, Gracillariidae, Lepidoptera) and aphid (Tuberculatus, Aphididae, Hemiptera) composition among Quercusdentata, Q. crispula, Q. serrata, and their hybrids

Leafminer (Phyllonorycter, Gracillariidae, Lepidoptera) and aphid (Tuberculatus, Aphididae, Hemiptera) composition were studied in three deciduous oak species, Quercus dentata, Q. crispula, and Q. serrata, and their hybrids in Tomakomai Experimental Forest of Hokkaido University, Hokkaido, northern Japan. Identification of trees in this forest was done mainly on the basis of discriminant analysis on leaf morphology with reference to trees in pure Q. dentata and Q. crispula stands and a Q. serrata stand mixed with Q. crispula. The results suggested that hybridization occurred in all combinations (i.e. Q. dentata–Q. crispula, Q. crispula–Q. serrata, and Q. serrata–Q. dentata) and the frequency of hybrids was approximately 10%. The composition of Phyllonorycter and Tuberculatus species differed between Q. dentata and Q. crispula or Q. serrata, but did not differ between Q. crispula and Q. serrata. Thus, Q. dentata could differ from Q. crispula and Q. serrata in chemical properties that determine herbivore host selection, survival, and performance, possibly reflecting eco-physiological differences or phylogenetic distances. The study insects were divided into three groups: species specialized to Q. dentata (three Phyllonorycter and one Tuberculatus species), those to Q. crispula and Q. serrata (six Phyllonorycter and two Tuberculatus species), and a species collected at least from Q. dentata and Q. crispula (one Tuberculatus species). Putative hybrid trees of Q. dentata and Q. crispula harbored both Q. dentata-specific and Q. crispula-specific insects.     

Cellulase in <Emphasis Type="Italic">Anoplophora glabripennis</Emphasis> adults fed on original host tree species and non-original host trees

Cellulase activities of Anoplophora glabripennis (Motsch.) adults from two host plants (Populus simonii × P.pyramidliscr cv.Opera Hsu.and Salix matsudana Koidz) fed on three different host tree species (Acer negundo Linn.,S.matsudana Koidz and P.simonii × P.pyramidliscr cv.Opera Hsu.) were investigated.Enzyme activities of endoglucanase and β-glucosidase in the intestines of the insects were measured.The results show that there are no statistically significant differences in the enzyme activities of endoglu...     

Phylogeography and host range of Armillaria gallica in riparian forests of the northern Great Plains,USA

Root disease pathogens, including Armillaria, are a leading cause of growth loss and tree mortality in forest ecosystems of North America. Armillaria spp. have a wide host range and can cause significant reductions in tree growth that may lead to mortality. DNA sequence comparisons and phylogenetic studies have allowed a better understanding of Armillaria spp. taxonomic diversity. Genetic sequencing has facilitated the mapping of species distributions and host associations, providing insights into Armillaria ecology. These studies can help to inform forest management and are essential in the development of disease risk maps, leading to more effective management strategies for Armillaria root disease. Armillaria surveys were conducted on publicly owned lands in North Dakota, South Dakota, and Nebraska, U.S.A. Surveyed stands consisted of riparian forests ≥0.4 hectares in area. Armillaria was found at 78 of 101 sites. A total of 57 Armillaria isolates—associated with 12 host tree species—were used for DNA sequencing of the translation elongation factor‐1 alpha (tef1) gene. Armillaria gallica was the only species identified within the study sites. Results suggest that A. gallica is a common root pathogen of hardwood trees in riparian forests of the northern Great Plains with a wider host range and geographic distribution than previously recognized.     

Long-term effects on tree regeneration of soil scarification with microtopography manipulation in mixed forests of central Hokkaido,northern Japan

Natural regeneration of canopy tree species is generally poor under a selective cutting regime practised in mixed conifer–hardwood stands on Hokkaido, northern Japan, and is prevented by dense bamboo layers in the understory. To promote tree regeneration, we scarified soil in ten sites, with elevations ranging from 420 to 760 m, in 1979, with a rake-equipped bulldozer to produce three different artificial microtopographies (concave, flat, and convex). Twenty-six years after scarification, six canopy tree species (Acer mono, Abies sachalinensis, Betula ermanii, B. maximowicziana, Kalopanax pictus, and Picea jezoensis) had become well established. Abies sachalinensis and B. ermanii regenerated at all sites. Picea jezoensis was well established in high-elevation sites, whereas other hardwood tree species (A. mono, B. maximowicziana, and K. pictus) were well established at low-elevation sites. The Betula species dominated upper layers of regenerated trees, and two conifer species (A. sachalinensis and P. jezoensis) occupied lower layers. Regenerated densities of four (of six) major tree species were positively correlated with standing timber volume of mother trees, whereas those of shade-intolerant species (two Betula species and K. pictus) were negatively correlated with standing timber volume of all canopy trees. Small-seeded species (P. jezoensis and the two Betula species) had higher regeneration densities on convex sites than on other microtopographies. Adequate seed supply, convex substratum for small-seeded species, and control of light conditions for shade-intolerant species should be taken into account when planning regeneration of desirable tree species in central Hokkaido.