bluuebunny/crossref_metadata_2025 huggingface dataset:
Inoculation trials with hypovirulent strains of Cryphonectria parasitica1
Authors: Turchetti T. , Maresi G.
Published: June 2007

Healing cankers were obtained in some artificial inoculation tests with combination of four hypovirulent strains of Cryphonectria parasitica which sporulated on the cankers.
Perspectives of disease threat in large‐scale Pinus radiata monoculture ‐ the New Zealand experience
Authors: Chou C. K. S.
Published: June 2007

Large scale P. radiata monoculture has been in existence in New Zealand for over 60 years. During this time a number of damaging diseases (e. g. Sirex‐Amylostereum, Dothistroma, Armillaria, Cydaneusma needle cast. Sphaeropsis die‐back etc.) have occurred but the impact was by no means devastating as these diseases are either controllable or in some the losses were deemed acceptable. As a large proportion of the biomass produced before age 10–12 is waste‐thinned, the acceptable level of disease loss is thereby very high. The practice of clear felling and short rotation reduces some of the disease risks common in other forest systems. Outlook for future disease threat is discussed with respect to current trends toward clonal forestry and the possible arrival of additional exotic pathogens.
Mechanism of cavitation development in the pine wilt disease
Authors: Kuroda K.
Published: June 2007

Volatile terpenes increase in xylem tissue after infection of Pinus thunbergii with the pine wood nematode (Bursaphelenchus xylophilus). The role of these terpenes in traeheid cavitation, which blocks xylem‐sap ascent and leads to water deficit in pine trees, was assessed. Volatile terpene concentration increased long before initiation of tracheid cavitation. After the volatile terpenes reached the highest concentration, severe cavitation developed. Direct injection of α‐pinene into healthy pine trunks formed artificial cavitation in xylem. These observations support the hypothesis that excessively produced volatiles, which are hydrophobic and have lower surface tension than water can promote tracheid cavitation in pine wilt disease.
Pseudocercospora kaiseri sp. nov. causing a necrotic leaf spot of Erythrina
Authors: Mehrotra M. D.
Published: June 2007

A new species, Pseudocercospora kaiseri, causing leaf spot of Erythrina stricta Roxb. from India is described and illustrated.
Water stress: A predisposing factor in the pathogenesis of Hypoxylon mediterraneum on Quercus cerris
Authors: Vannini A. , Scarascia Mugnozza G.
Published: June 2007

Hypoxylon mediterraneum (De Not.) Mill. proved to be a weakness parasite on Quercus cerris. Evidences are given about the association between pathogenicity of the fungus and water stress of the host.
Pathogenic variation in Cylindrocladium quinqueseptatum causing leaf blight of Eucalyptus1
Authors: Sharma J. K. , Mohanan C.
Published: June 2007

A wide range of pathogenic variation was observed among the five isolates of Cylindrocladium quinqueseptatum leaf blight (CLB) which could be distinguished as different physiologic strains on 11 differential provenances of Eucalyptus. Susceptibility ranking of different provenances to five isolates also differed significantly indicating differential interaction between isolates and provenances. Analysis of variance showed that CLB severity of a provenance is mainly governed by the genetically different isolates and also that the provenances have closer genetical relationship. The results provide the first evidence for the existence of physiologic strains in C. quinqueseptatum.
Pathogenic variability of various isolates of Seiridium cardinale, S. cupressi and S. unicorne inoculated on selected Cupressus clones and seedlings
Authors: Xenopoulos S. G.
Published: June 2007

Comparative studies of the pathogenicity of eight isolates of three Seiridium species were carried out by stem inoculations on Cupressus sempervirens and C. glabra seedlings and clones. Seiridium cardinale and S. cupressi caused bigger and more severe cankers than all strains of S. unicorne. During the first nine months after inoculation, the canker length of S. cardinale was larger than the cankers of S. cupressi. However, during the second year after inoculation, S. cupressi cankers were larger and more severe than those of 5. cardinale.
Oak decline: I. Fungi associated with various disease symptoms on overground portions of middle‐aged and old oak (Quercus robur L.)
Authors: Kowalski T.
Published: June 2007

Fungi colonizing overground portions of Quercus robur art presented separately for each of the following types of disease symptoms: leaves with atrophy and necrotic areas, dead branches, dead tops of branches, dead water sprouts, local necrotic areas in bark and phloem, locally dead and discoloured sapwood in debarked places, local discolorations inside sapwood, extensive nec‐rotic areas on stems, dead trees. Over 80 species of fungi were found in all, mainly from As‐comycotina and Deuteromycotina. Connected with each type of symptom there were several species of fungi which were more frequent than the remaining ones. In most cases fungi seem to be of secondary importance in development of symptoms characteristic for oak decline.
Life cycle of Lophodermium piceae in Norway spruce needles
Authors: Osorio M. , Stephan B. R.
Published: June 2007

The spruce needle inhabiting ascomycete Lophodermium piceae can live symptomless for several years, before it completes its life cycle within less than one year as detailed studies have shown.
Markstrahlenkrankheit der Buche (Fagus sylvatica): Anatomische Beschreibung und mogliche Entstehungsursache
Authors: Von Kučera L. J. , Bonsen K. J. M.
Published: June 2007

The beech ray disease, an abnormal structure of the rays associated with discolorations, is de‐scribed macroscopically as well as microscopically. A SEM study indicated the presence of bac‐teria, which apparently influence the activity of the cambial tissue.
Variation in the susceptibility of lodgepole pine provenances to Sirococcus shoot blight: results from artificial inoculations
Authors: Hamelin R. C. , Sutherland J. R.
Published: June 2007

Fourteen provenances of lodgepole pine artificially inoculated with a local isolate of Sirococcus strobilinus varied in their susceptibility to the pathogen. Provenances from the Dry Interior (31.9%) and the Sierra (14.3%) had significantly lower disease incidence than those from the Interior Wet Belt (51.9%), the Coast (62.5%) and the Cascade Range (58.6%). These results indicate the potential for selecting seed sources with low levels of susceptibility to Sirococcus shoot blight.
Disease history of Gremmeniella abietina in a Pinus sylvestris stand
Authors: Kaitera J. , Jalkanen R.
Published: June 2007

A new method has been developed for studying the history of Gremmeniella abietina infection in Scots pine (Pinus sylvestris) stands. The branch analysis method is based mainly on the occurrence of necrotic cankers and scars caused by G. abietina in annual shoots of branches. The supporting factors are the number of leader changes of branches and branch death model.
Scanning electron microscopy of mycoparasitism of Armillaria rhizomorphs by species of Trichoderma
Authors: Dumas M. T. , Boyonoski N. W.
Published: June 2007

Scanning electron microscopy showed that Trichoderma polysporum, T. harzianum and T. viride were mycoparasites on the rhizomorphs of Armillaria gallica. These Trichoderma species attacked and penetrated the melanized outer tissue of the rhizomorph and once inside they killed the Armillaria hyphae by coiling and direct penetration. After one week the rhizomorphs infected with each of the three species of Trichoderma were devoid of hyphae.
Lophodermium piceae and Rhizosphaera kalkhoffii in fallen needles of Norway spruce (Picea abies)
Authors: Livsey Susan , Barklund Pia
Published: June 2007

Falling needles collected from under individual 70‐year‐old Norway spruce (Picea abies) trees for about four years were checked for fungal fruitbodies. The most common fungi were Lophodermium piceae and Rhizosphaera kalkhoffii. Maximum frequencies of fruitbodies occurred in late autumn for L. piceae (ca. 80% of the needles), in summer for R. kalkhoffii (ca. 60%) and in winter for the third most common fungus, Tiarosporella parca (ca. 10%). The frequencies of needles with fruiting fungi varied greatly within and between years. This is the first report of T. parca from Sweden.
Antagonistic effects of saprophytic bacteria to Dothichiza populea
Authors: Avramović G. , Arsenijević M.
Published: June 2007

Bacteria were isolated from both poplar and other plant species. Antagonistic effects of these bacteria on growth and germination of Dothichiza populea were tested. A total of 195 bacterial isolates were collected, but only 12 isolates from poplars and 31 isolates from other hosts distinctly reduced growth of D. populea in dual cultures. Some of these growth inhibiting isolates were also examined for their influence on germination of pycnospores. Only some bacterial isolates from poplars inhibited germination, whereas others even stimulated it. On the other hand, all isolates from other hosts than poplars significantly reduced germination rate.
Cellulose is degraded during phloem necrosis of Hevea brasiliensis
Authors: Nicole M. , Chamberland H. , Nandris D. , Ouellette G. B.
Published: June 2007

A cytochemical investigation was performed for studying cellulose alteration during phloem necrosis of the rubber tree. An exoglucanase‐gold complex was used for localizing β‐(1,4)‐D‐glucan linkages of non reducing ends of the polymer. Variation in cell wall labelling indicates that cellulose is degraded during this disease and suggests that cellulases are involved in this alteration. Wall appositions and periplasmic vesicles were also observed.
Penetration of Cronartium flaccidum into pine needles
Authors: Ragazzi A. , Fedi Irene Dellavalle
Published: June 2007

The penetration of Cronartium flaccidum into the cotyledons, primary needles and secondary needles of Pinus pinaster and P. nigra var, laricio was investigated.

SEM examination showed that the fungus did not form appressoria and that the germ tube penetrated directly into the stomata.
New type of damage to Quercus ilex: pollen germination and hydration ability
Authors: Bellani Lorenza M. , Paoletti E.
Published: June 2007

Pollen grains collected from trees of Quercus ilex L. belonging to different classes of new type damage were analyzed. Five parameters were taken into account: viability, germinability, tube lengthening, grain volume of the dehydrated state and after rehydration. Damage to mother plants clearly influences the above mentioned parameters, causing a reduction in pollen grain viability, germinability, and in the ability of the grains to rehydrate.
Electrophoretic protein profiles of strains of Ceratocystis fimbriata f. sp. platani
Authors: Granata G. , Parisi A. , Cacciola S. O.
Published: June 2007

Soluble proteins extracted from the mycelium of strains of Ceratocystis fimbriata (Ell. et Halst) Davidson f. sp. platani Walter were separated on native and SDS‐polyacrylamide gradient gel electrophoresis. The protein patterns were compared and the electrophoretic profiles of all the strains examined showed striking intraspecific similarities. The use or protein banding patterns as a diagnostic criterion to distinguish strains of C. fimbriata is discussed.
Viruslike particles associated with ringfleck mosaic of mountain ash and a mosaic disease of raspberry in the Bavarian Forest
Authors: Ebrahim‐Nesbat F. , Izadpanah K.
Published: June 2007

Two types of spherical viruslike particles measuring ca. 25–30 nm and 80 nm in diameter, respec‐tively, were found both in ringfleck mosaic affected mountain ash and adjacent raspberry bushes in the Bavarian Forest. The smaller particles were also found in symptomless mountain ash in the same forest. The sap from infected mountain ash reacted with an antiserum to tomato spotted wilt virus in agar‐gel‐diffusion test. No reactions were obtained with raspberry or mountain ash sap when tested against antisera to a number of small spherical plant viruses.
Stilbenes and resin acids in relation to the penetration of Heterobasidion annosum through the bark of Picea abies
Authors: Lindberg M. , Lundgren L. , Gref R. , Johansson M.
Published: June 2007

Concentrations of the stilbene glucosides astringin and isorhapontin, which ranged from 5 to 50 mg/g fresh weight in Picea abies bark, decreased in response to in vivo infection with the root‐rot fungus Heterobasidion annosum. The initial concentration of the stilbene astringin was negatively correlated with the depth of hyphal penetration. Resin acid contents increased following infec‐tion, but were not correlated with the depth of hyphal penetration. The spatial distribution of stilbene glucosides in spruce stem, root collar and root bark, and the seasonal variations in con‐centration, were estimated.
Observations on some Italian provenances of Melampsora populnea
Authors: Naldini B. , Longo N. , Drovandi F. , Gonnelli T. , Moriondo F.
Published: June 2007

In some Italian provenances of Melampsora populnea on Populus tremula from mountain zones, the presence of Melampsora pinitorqua was tested through teliospore germinability tests and sub‐sequent basidiospore inoculations. In this study the risk of twist rust epidemics in new planta‐tions is discussed.
Endophytische Pilze in Blättern und Zweigen von Quercus petraea
Authors: Von Halmschlager E. , Butin H. , Donaubauer E.
Published: June 2007

Endophytic fungi in leaves and twigs of Quercus petraea. Surface sterilized leaf and twig samples taken in 1989 from sessile oak (Quercus petraea) in Austria yielded host‐specific as well as unspecific ubiquistic endophytes. In leaves, Aureobasidium apocryptum and Apiognomonia quercina were the most frequent taxa, while Colpoma quercinum was the dominant species in twigs. The colonization rates of individual species were subjected to seasonal variation.
Histopathology of loblolly pine needles infected by Mycosphaerella dearnessii, the brown‐spot needle disease pathogen
Authors: Jewell F. F.
Published: June 2007

The histopathology of green Pinus taeda needles infected with Mycosphaerella dearnessii was investigated. Cellular abnormalities observed were predominately the collapse of mesophyll cells within the limits of the symptom lesions. The epidermis, hypodermis, endodermis, transfusion tissue, and the vascular system within the lesions were not affected. Resin ducts exhibited cell necrosis and dissolution within and distal from the visible limits of lesions. An intercellular interface was present in non‐collapsed mesophyll cells at lesion limits, and the lateral extension of the interface usually corresponded to the effects observed in resin ducts distal from the lesions. Non‐stromatic hyphae were rare in and distal from lesion tissue, indicating the host tissues were affected in advance of the pathogen. The production of a toxin by M. dearnessii is suspected.
Reproductive success of Bursaphelenchus xylophilus and B. mucronatus at constant and fluctuating temperatures
Authors: Tomminen J.
Published: June 2007

Reproductive rates of three North American isolates ofBursaphelenchus xylophilusand a Finnish isolate ofB. mucronatuswere compared by culturing the nematodes at constant and at daily fluctuating temperatures in the laboratory and in the field.Botrytis cinereaandPinus sylvestriswood were used as nutrient sources. In general, theB. xylophilusisolates reproduced better than theB. mucronatusisolate at constant temperatures, whereas the situation was reversed at fluctuating temperatures.
Spatial and temporal characteristics of canopy gaps caused by Armillaria root disease and their management implications in lowveld forests of South Africa
Authors: Lundquist J. E.
Published: June 2007

Roadside reconnaissance and aerial photo surveys were used to characterize the frequency and size of canopy gaps caused by Armillaria root disease in 1763 stands of Pinus spp. in the eastern Transvaal, South Africa. Root disease occurred in 290 stands, most of which grew at altitudes 1000 m. Pinus elliottii was the most commonly infected host, followed by P. kesiya, P. roxburghii, P. caribaea, P. taeda, and P. patula. Disease severity (proportion of stand area with gaps) increased rapidly to age 3, remained nearly constant between ages 6–17, increased rapidly again between 17–28, and then decreased abruptly between ages 28–40. Gap incidence (proportion of all stands with gaps) rapidly increased to age 10, after which it remained nearly constant. Host species present in previous stands influenced whether disease developed in current stands.
Growth of Gremmeniella abietina on artificial media simulating the effects of mineral nutrient imbalance of Scots pine
Authors: Ylimartimo Anneli , Haansuu P.
Published: June 2007

Increased foliar N/K and N/Mg ratios are known to reduce the resistance of Pinus sylvestris to scleroderris canker caused by Gremmeniella abietina. The aim of this work was to study how such changes in nutrient levels affect the growth of the pathogen in vitro. The mycelium of the pathogen was grown on artificial media adjusted to simulate the changes in inorganic N, K, Mg and Ca and free amino acid concentrations in the host with nutritional imbalance. Increased concentrations of K and Ca reduced the mycelial growth of the pathogen, whereas a modest increase in the concentration of inorganic N increased the growth. Tenfold concentrations (compared with normal host levels) of arginine and glutamic acid, and up to one hundred‐fold concentrations of proline increased the mycelial growth. The results suggest, that nutrient imbalances may enhance the colonization of host tissues by G. abietina.
Susceptibility of four conifer species to Gremmeniella abietina
Authors: Aitken Elizabeth A. B.
Published: June 2007

G. abietina causes severe dieback in pole‐stage stands of Scots pine in Britain. The susceptibility of ll provenances of Scots pine and of three other conifer species was tested by inoculations. Significant differences in susceptibility were found amongst Scots pine provenances, with those originating from a native Scottish pinewood at Loch Maree showing the highest levels of disease. Corsican pine was shown to be the most susceptible species tested although sporulation was greatest on Scots pine. Norway spruce was also shown to be susceptible when inoculated late in the growing season. Infection in lodgepole pine was negligible. High levels of β‐phellandrene were tentatively linked with resistance among trees in a single stand of Scots pine.
Pilzentwicklung in Fichtenholz unter Schutzgasatmosphäre
Authors: Metzler Von. B. , Gross M. , Mahler G.
Published: June 2007

Fungal growth in spruce timber stored under low oxygen atmosphere. Fungal growth and species composition in Norway spruce timber (Picea abies) stored under an atmosphere with low oxygen concentration was monitored by isolation techniques. The results were compared with those from unprotected wood and from living trees. The role of potentially antagonistic fungi is discussed.
Conidial germination and formation of necrosis in pine seedlings by Gremmeniella abietina at low temperatures
Authors: Petäistö Raija‐Liisa
Published: June 2007

The germination of conidia of G. abietina on water agar reached the same germination percentage at 0°C as at 5 °C to 12.5 °C, but required more time. The fungus caused necrosis even at ‐ 4 °C in pine seedlings.
The ability of Gremmeniella abietina to hydrolyze polygalacturonic acid
Authors: Petäistö Raija‐Liisa , Kajander E. O.
Published: June 2007

Gremmeniella abietina grew well in media with pectin as the sole carbon source. The fungus secreted at least one enzyme with polygalacturonase activity, and this was induced by addition of pectin to the culture medium.
Effectiveness of compartmentalization of wound‐initiated discoloration in red spruce trees of two forest stands
Authors: Smith K. T. , Shortle W. C.
Published: June 2007

The effectiveness of compartmentalization following wounding was tested in red spruce trees at two locations in the northeastern United States. The test provided a basis to rank the two forest stands on the basis of the effectiveness of compartmentalization.
Suberin degradation by Rosellinia desmazieresii
Authors: Ofong A. U. , Pearce R. B.
Published: June 2007

In culture, Rosellinia desmazieresii, the agent of a ring‐dying disease in Salix repens, which can penetrate intact periderm surfaces in its host, produced a range of cell‐wall‐degrading enzymes. These included esterases that may be important in the depolymerization of suberin. Slow breakdown of suberin by this fungus was demonstrated.
Pythium and Phytophthora species associated with eucalypts and pines in South Africa
Authors: Linde C. , Kemp G. H. J. , Wingfleld M. J.
Published: June 2007

Root and soil samples from Eucalyptus and Pinus plantations taken during routine surveys of South African forestry areas during 1990–1992, yielded various species of Pythium and Phytophthora. These include three species of Phytophthora and 20 species of Pythium. Six of these Pythium species have not previously been recorded in South Africa. The pathogenicity of the Pythium and Phytophthora spp. collected during the surveys was tested on established Eucalyptus fastigata and a clone of E. grandis.
Der Einfluß gasförmiger Luftschadstoffe auf die EpicuticularWachse von Quercus robur
Authors: NEINHUIS C. , WOLTER M. , KÜPPERS K. , BARTHLOTT W.
Published: June 2007

Influence of gaseous pollutants on the epicuticular wax of Quercus robur. The effects of SO2, NO, and ozone on the epicuticular wax of Q. robur were studied by scanning electron microscopy and by measuring the contact angle of water droplets on the leaf surfaces. The treatments did not induce any significant differences in the wax micromorphology.
The ability of the pine‐top weevil to carry spores and infect Scots pine with Endocronartium pini
Authors: Pappinen A. , von Weissenberg K.
Published: June 2007

The pine‐top weevil Pissodes piniphilus is known to be often associated with trees infected with resin‐top disease. In this paper, the ability of the weevil to carry Endocronartium pini spores in laboratory conditions and its ability to infect pines in the field were studied. The weevil may carry spores and cause infection in healthy pines.
The effects of Taphrina betulina infection on growth of Betula pubescens
Authors: Spanos Y. A. , Woodward S.
Published: June 2007

The impact of infection by Taphrina betulina on the growth of Betula pubescens was studied in naturally regenerated stands in the North East of Scotland. Infection by T. betulina was associated with a significant reduction in height growth and poorer developmental tendency, vigour, and stem quality of B. pubescens, whereas diameter at breast height was little affected. Tree height was reduced by an average of 25% over all diameter classes, with the greatest effect in smaller trees. For brooms of 100 mm diameter and over, numbers and sizes were strongly correlated with diameter at breast height and tree age. Reductions in height and vigour were not correlated with the number and size of brooms present, but were more pronounced in younger, smaller trees.
Effects of temperature, relative humidity and time on survival of pinewood nematodes in wood chips
Authors: Panesar T. S. , Peet F. G. , Sutherland J. R. , Sahota T. S.
Published: June 2007

The survival of two Canadian isolates of the pinewood nematode, Bursaphelenchus xylophilus, in coniferous wood chips under different temperatures, relative humidities and time intervals was investigated in vitro. The nature of the survival mechanism was examined and it was shown that the nematode's prolonged survival in the chips depended on its dispersal third larval stage. The possibility of PWN‐infested wood chips spreading PWN‐induced pine‐wilt disease to forests is discussed.
Picea omorika— a new host of Dothistroma septospora
Authors: Karadží D. M.
Published: June 2007

D. septospora is recorded for the first time on young Serbian spruces. In addition to Serbian spruce, the fungus was also observed on Douglas fir. Based on the length of conidia it was concluded that it was D. septospora var. lineare.
Morphology of epicuticular waxes in Pinus pinea needles in relation to season and pollution‐climate
Authors: Altieri A. , Del Caldo L. , Manes F.
Published: June 2007

Micromorphological change of the epicuticular wax structure in Pinus pinea needles was analysed by scanning electron microscope and the relationships between the rates of wax weathering over seasons and the pollution‐climate at one urban and two rural sites arediscussed.
Die Wachstumsgeschwindigkeit als Unterscheidungsmerkmal zwischen Ophiostoma piceae und Ophiostoma querci
Authors: Wulf A. , Kowalski T.
Published: June 2007

Vegetative growth as a means of differentiating Ophiostoma piceae from Ophiostoma querci. Isolates of Ophiostoma piceae from spruce (Picea abies) and O. querci from oak (Quercus robur) showed distinct differences in vegetative growth of cultures at a wide range of temperatures.
Variation in combined fatty acid and sterol profiles of Ascocoryne, Nectria, and Neobulgaria‐strains isolated from Norway spruce
Authors: Müller M. M. , Hallaksela Anna‐Maija
Published: June 2007

The diversity of Ascocoryne cylichnium, Nectria fuckeliana and Neobulgaria premnophila isolates expressed as variation in their fatty acid and sterol composition was investigated. Despite high within‐species variation, distinct differences in the fatty acid and sterol composition between species were evident.
Identification of gram‐positive bacteria isolated from initial stages of wound‐initiated discoloration of red maple
Authors: Parker Sharon , Shortle W. C. , Smith K. T.
Published: June 2007

Similar gram‐positive bacteria in the genera Bacillus and Actinomyces were isolated from sapwood and stage‐one discolored wood of red maple. These isolates are unlike those previously reported from red maple wood in advanced decay.
Detection of mycoplasmalike organisms in declining oaks by polymerase chain reaction
Authors: Ahrens U. , Seemüller E.
Published: June 2007

By polymerase chain reaction, mycoplasmalike organisms (MLOs) were detected in several declining trees of Quercus robur sampled at two locations of Germany. The MLOs associated with declining oaks were, within the 16S rDNA studied, genetically uniform and closely related to the MLOs associated with European stone fruit yellows and apple proliferation.
Excess nitrogen fertilization and the structure of Scots‐pine needles
Authors: Jokela A. , Bäck J. , Huttunen S. , Jalkanen R.
Published: June 2007

The effects of excess nitrogen fertilization on the structure of Scots‐pine needles (Pinus sylvestris) were examined in Finnish Lapland. The trees were fertilized with calcium ammonium‐nitrate, and the levels of nitrogen applied were 0, 75, 150, 250, 500 and 1000 kg N/ha, respectively. The thickness and width of the needle and thicknesses of the tissues were measured, and the conditions of various celltypes were classified at the light‐microscopy level. In addition, the areas of the cell organelles were measured and the conditions of the chlomplasts and other cell compartments observed at the ultrastructural level. Larger needles and a thicker adaxial mesophyll were observed following excess N application (250–1000 kg N/ha). The natural xeromorphic structure of the conifer needles became more mesomorphic, possibly influencing the protection afforded against environmental stresses. A high level of nitrogen fertilization caused changes in the central cylinder, especially in the vascular bundle and the sclerenchyma. The needle nitrogen concentration was high in the highly fertilized trees and the boron concentration was simultaneously extremely low. As a consequence of the changes in the central cylinder, photoassimilate transport from the mesophyll to the phloem may be disturbed at high fertilization levels. The changes at the ultrastructural level, i.e. injuries to the chloroplast thylakoids and the plasma membrane, and the formation of lipid accumulations, were indicators of the adverse effects of excess nitrogen. With an increasing atmospheric‐nitrogen load, lower nitrogen fertilization levels in pine forests naturally adapted to low soil N should be considered in forest management.
Pathogenicity of Colletotrichum dematium isolated from current‐year beech seedlings exhibiting damping‐off
Authors: Sahashi N. , Kubono T. , Shoji T.
Published: June 2007

The pathogenicity of Colletotrichum dematium was evaluated as the agent causing post‐emergence damping‐off of current‐year beech (Fagus crenata) seedlings. Current‐year beech seedlings inoculated with C. dematium died within 20 days after both wound and non‐wound inoculation, indicating that this fungus is pathogenic to current‐year seedlings.

C. dematium was frequently isolated from hypocotyls exhibiting damping‐off at five different sites. The incidence of isolation was high and little variation occurred between sites and years. C. dematium was also detected in all litter samples examined although the incidence of detection differed depending on sites and/or detection methods.

These results strongly indicate that C. dematium plays an important role in rapid seedling death during the early stages of beech regeneration.
Preliminary evaluation of Epicoccum purpurascens as a biocontrol agent against wound pathogens on stems of Picea abies
Authors: Zimmermann M. , Sieber T. N. , Holdenrieder O.
Published: June 2007

Epicoccum purpurascens was applied to stem wounds of Norway spruce for a preliminary assessment of its potential as a biological protection against decay fungi. E. purpurascens had a significant influence on the composition of the mycoflora of the wounds, analysed 8 months after inoculation.
Changes in soluble‐phenol content of Norway‐spruce (Picea abies) phloem in response to wounding and inoculation with Ophiostoma polonicum
Authors: Brignolas F. , Lieutier F. , Sauvard D. , Yart A. , Drouet A. , Claudot A. C.
Published: June 2007

The aim of this study was to investigate the temporal changes in Norway‐spruce (Picea abies) phloem phenolics during wound‐induced response. Two Norway spruces were inoculated with Ophiostoma polonicum and sterile agar; unwounded phloem was simultaneously tested as control. Both unwounded and inoculated phloem were then sampled 6, 11, 21, 30, and 60 days later. Monophenols were analysed by HPLC, and the tanning capacity of the phloem extracts was estimated from their ability to precipitate proteins. The response to inoculation was characterized by radical changes in the phloem phenolic composition. Initially, an increase in (+)‐catechin concentration was observed, concomitant with a slow decrease in both glycoside concentrations and tanning capacity. After day 6, this decrease was accelerated in the event of fungus inoculation. The appearance of aglycones did not take place during the decrease in glycosides, but was delayed. The phenolic response of Norway‐spruce phloem to inoculation is modulated by the presence of the fungus and is focused on the formation of insoluble compounds.
Chemical and structural barriers toMicrocyclus ulei, the agent of South American leaf blight, inHeveaspp.
Authors: Garcia D. , Cazaux E. , Rivano F. , D'Auzac J.
Published: June 2007

Young leaves of different rubber‐tree clones were inoculated withMicrocyclus uleiunder controlled conditions. Under ultraviolet light, intense blue fluorescent light was emitted from the penetration site 6 h after inoculation. The speed of the appearance of this fluorescence was related to the degree of resistance of the clones: 12–36 h in totally resistant clones, 36–120 h in marked partially resistant clones, and 120 h in weak partially resistant clones. The source of this fluorescence may have been scopoletin. Strong accumulation of this coumarin may inhibit pathogen invasion in a very early phase. Four days after inoculation, intense accumulation of lignins in only a few cells at the penetration sites was observed in totally resistant clones. Intense lignin accumulation around lesions may also stop pathogen development in some partially resistant clones
Growth of axenic cultures of Cronartium flaccidum on callus tissue from Pinus nigra var. laricio and Pinus sylvestris
Authors: Ragazzi A. , Moricca S. , Dellavalle I.
Published: June 2007

The callus‐fungal method was employed to test the response to C. flaccidum of the highly susceptible P. nigra var. laricio and the resistant P. sylvestris, and to ascertain whether results obtained with this method matched in planta observations. Calli were inoculated with axenie cultures of C. flaccidum obtained by incubating basidiospores on modified Schenk and Hildebrandt medium. Several parameters were evaluated. Colony growth was more rapid on P. nigra var. laricio. Colonies were dense on P. nigra var. laricio, but sparse on P. sylvestris. Aerial hyphae growth was abundant on P. nigra var. laricio, but less frequent on P. sylvestris. Hyphal branching began after 18 h on P. nigra var. laricio and after 45 h on P. sylvestris. Necrosis of the host cells set in after 24 h on P. nigra var. laricio, and after 70 h on P. sylvestris. The number of cells with plasmolysis was much larger in P. nigra var. laricio than in P. sylvestris. These results were consistent with the known resistance of the two species on whole plants.
Armillaria species associated with Gastrodia elata in Japan
Authors: Cha J. Y. , Igarashi T.
Published: June 2007

Gastrodia elata was collected from July to August 1992 in Hokkaido forests. A total of 22 diploid isolates were paired with haploid testers of the biological Armillaria species reported in Hokkaido. One isolate was identified as A. ostoyae, 10 as A. gallica, three as A. jezoensis, three as A. sinapina, and five as A. singula. These isolates were compatible with the respective Hokkaido testers of these species. With the exception of A. ostoyae, these species are known as saprophytes, which form abundant rhizomorphs in soil.

Clear isozyme profiles of esterases were obtained with all isolates except one. Interspecific variations were more important than intraspecific variations. The esterase profiles could be used for identification of the Armillaria species in Hokkaido as a useful complement to the mating‐type method.
Detectability of wood decay caused by Ustulina deusta in comparison with other tree‐decay fungi
Authors: Schwarze F. W. M. R. , Lonsdale D. , Mattheck C.
Published: June 2007

Two devices were evaluated for the inspection of wood decay caused by Ustulina deusta (Hypoxylon deustum, the‘Metriguard’stress‐wave timer for decay detection, and the‘Fractometer’, a sample corebreaking gauge, for measurement of the loss of strength. The stress‐wave timer failed to detect decay caused by the fungus in naturally infected trees or jinoculated wood blocks, but detected decay in wood blocks from various tree species inoculated with the white‐rot basidiomycetes Fomes fomentarius, Ganoderma pfeifferi, and Polyporus squamosus, and the brown‐rot basidiomycete Leatiporus sulphureus. The Fractometer showed large losses of strength in inerement cores incubated with all the test fungi, including U. deusta, even at an early stage of decay. The patterns of cell‐wall degradation, as shown by light microscopy, were consistent with the observed brittle nature of deeay caused by U. deusta and with the results of testing the two devices. Both in naturally infected trees and in wood bloeks, early degradation took the form of a soft‐rot, with cavity formation in the S2 layer of the secondary cell walls. A white‐rot supervened, but with prolonged persistence of a brittle, lignin‐iich 'skeleton’that appeared to transmit stress‐waves with little alteration in velocity.
The ability ofOphiostoma clavigerum to kill mature lodgepolepine trees
Authors: Yamaoka Y. , Hiratsuka Y. , Maruyama P. J.
Published: June 2007

Lodgepole pine, Pinns contorts var. latifolia, about 80 years old, inoculated in the field with Opbiostoma clavigerum either alone or in combination with Opbiostoma montium died within 1 year of inoculation, but the trees inoculated with O. montium or control inoculum did not.
Hosts and distribution of the intersterility groups of Heterobasidion annosum in the highlands of Greece
Authors: Tsopelas P. , Korhonen K.
Published: June 2007

The intersterility groups of 127 pure cultures of H, annosum collected from different host trees in 12 mountain areas in Greece were identified. The F group commonly caused butt rot on the fir species Abies cephalonica and Abies borisii regis. It was the only type of H. annosum found in pure fir forests. The P group caused serious root rot in pinus sylvestris stands in north‐eastern Greece. In more southern mountain areas it often colonized stumps of pinus nigra but seldom killed this tree species. The S group was found in natural forests of Picea abies in northern Greece, causing butt rot of spruce. In mixed forests, the intersterility groups of H. annosum were found relatively often in stumps of tree species other than their main hosts, although some host preference seemed to occur also in stump colonization.
Factors affecting discharge and germination of ascospores of Hypoxylon mediterraneum (De Not.) Mill.
Authors: Vannini A. , Paganini R. , Anselmi N.
Published: June 2007

Discharge and germination of ascospores of Hypoxylon mediterraneum (=Biscogniauxia mediterranea (De Not.) O. Kuntze) were studied. Discharge and germination of ascospores depend on the presence of water or high relative air humidity. Ascospores are ejected from stromata in forest for most of the year following periods of high precipitation.

H. mediterraneum ascospores germinated under a wide range of biotic and abiotic conditions. The optimal temperature for germination was 35°C, but 25 and 30°C were still favourable, while 20 and 40°C reduced germination. Ascospores kept at 5°C were able to germinate after short exposure to temperatures ranging from 20 to 35°C. Germination rate depended on the ascospore density in in vitro experiments, and was highest at 106 ascospore/ml.

Tissues of some host plants greatly increased germination rate. In vivo, ascospores germinated better on wounded axillary tissues than on unwounded ones.
Fusarium canker of Italian cypress
Authors: Madar Z. , Kimchi M. , Solel Z.
Published: June 2007

A new disease, causing mortality of Italian cypress (Cupressus sempervirens) trees cv. ‘Totem', was observed in an Israeli nursery. Fusarium compactum was isolated from cankers, and its pathogenicity was confirmed by Koch's test. The fungus readily formed conidia and chlamydospores in PDA culture. Growth of F. compactum was fastest at 26–30°C. Artificial inoculations with F. compactum caused severe cankering of several species of each of the following coniferous genera: Cupressus, Juniperus, Tetraclinis, Thuja, Cedrus and Pinus. Canker development was significantly enhanced when extreme water stress was imposed on cypress saplings prior to inoculation.
Isolation, identification and pathogenicity of Phytophthora species from declining oak stands
Authors: Jung T. , Blaschke H. , Neumann P.
Published: June 2007

Within the scope of a research project on the condition of roots of declining oaks (Quercus robur, Quercus petraea), samples of fine roots and surrounding soil, specimens of stripe cankers on the stem base, and samples of stream water were examined for the presence of Phytophthora species using both baiting methods and selective agar media. At 27 sites in Germany (Bavaria, Rheinland‐Pfalz, Schleswig‐Holstein), Switzerland, Hungary, Italy and Slovenia the following species were isolated (mainly from soil): Phytophthora citricola, Phytophthora cactorum, Phytophthora cambivora, Phytophthora gon‐apodyides, Phytophthora undulata, a species with affinity to Phytophthora drechsleri, and two additional species with close affinity to the Phytophthora cactorum group. Moreover, Pythium group P, Pythium anandrum, Pythium chamaehyphon, and many other Pythium species that have not yet been identified could be recovered. In a soil infestation test most isolates induced dieback of long root tips and necrotic lesions in the root cortex and at the root collar of Quercus robur seedlings. All Phytophthora species tested and Pythium group P caused cortical necrosis after stem inoculation of young Quercus robur trees. It could be shown in vitro that Phytophthora gonapodyides and Pythium group P were able to produce a wilting toxin. Nitrogen input and climatic changes are discussed as predisposing factors for root damage observed in the field.
Fungi in bark peeling wounds of Picea abies in central Sweden
Authors: Vasiliauskas R. , Stenlid J. , Johansson M.
Published: June 2007

A total of 210 Norway spruce trees with stem wounds resulting from bark peeling by moose (Alces alces) were examined in three 45–50‐year‐old stands that contained 20‐30% of damaged trees. Injured stems were between 8 and 40 cm diameter at breast height (d.b.h.) and showed 1 to 23‐year‐old wounds. Wounds varied in size from 2 to 4815 cm2. The size of injury correlated negatively with the age of the injury (r=‐0.24; p=0.004), and positive correlation was established between the age of the injury and d.b.h. of the wounded tree (r=0.50; p=0.0001). Each wound was sampled once using an increment borer and fungi were isolated. Among basidiomycetes, Stereum sanguinolentum was the most common (isolated from 26.7% of the damaged stems). Other common species were Cylindrobasidium evolvens (23.8%), Amylostereum areolatum (5.2%), A. chailletii (0.5%), Heterobasidion annosum (5.2%), Peni‐ophorapithya (1.4%), Sistotrema brinkmannii (1.0%). The ascomycete Nectria fuckeliana was the most common among all fungi (present in 35.7% of bark peeling wounds). The frequency of S. sanguinolentum infection correlated positively with the age of the injury (r=0.27; p=0.001) and the opposite relationship was revealed for C. evolvens (r=−0.30; p=0.0001). Furthermore, C. evolvens infection correlated positively with the wound size (r=0.30; p=0.0001) and negatively with the tree d.b.h. (r=−0.20; p=0.004). A positive correlation was found between tree d. b. h. and the occurrence in stems of H. annosum (r=0.23; p=0.001 and N. fuckeliana (r=0.23; p=0.0006). The spruce bark beetle Dendroctonus micans attacked 14.8% of wounded trees. Presence in stems of N. fuckeliana was associated significantly with the D. micans attack (r=0.190; p =0.006; χ2 test: p=0.01). Except for a negative correlation between infections of S. sanguinolentum and H. annosum (r=‐0.140; p=0.04), no significant relationship between fungal species was found.
Chitin and glucans detected in the cell walls of Pythium dimorphum—an oomycetous fungus
Authors: Asiegbu F. O. , Lönneborg A. , Johansson M.
Published: June 2007

With aid of fluorescein isothiocyanate (FITC) and gold‐labelled lectins, together with antibodies against chitinase and β‐1,3‐glucanases, the spatial distribution of chitin and glucans in hyphal walls of Pythium dimorphum, a causative agent of root die‐back disease of conifer seedlings was studied. Contrary to previous reports, this study revealed that chitin, a polymer of N‐acetyl‐d‐glucosamine, is a component of the cell wall of this oomycetous fungus. However, compared with the other amino sugar, N‐acetyl‐galactosamine, it is not present in significant amounts. Ultrastructural and labelling studies demonstrated that the chitin region is embedded in or masked by glucan residues.
Identification and characterization of the phytoplasma associated with elm yellows in southern Italy and its relatedness to other phytoplasmas of the elm yellows group
Authors: Marcone C. , Ragozzino A. , Seemüller E.
Published: June 2007

In the neighbouring regions Basilicata, Campania, and Calabria of southern Italy, diseased trees of European field elm (Ulmus minor) were examined for phytoplasmal infection using polymerase chain reaction (PCR) technology. All affected trees examined tested positively. Using a primer pair specific for the EY phytoplasma group and restriction fragment length polymorphism (RFLP) analysis of PCR‐amplified ribosomal DNA, the organism detected was identified as the elm yellows (EY) phytoplasma. RFLP analysis of PCR‐amplified ribosomal DNA was also employed to attempt differentiation within the EY group which includes, in addition to the EY agent, phytoplasmas infecting Rubus, alder, eucalypts, Spanish broom, and grapevine. Following separate digestion with AluI, RsaI, Sau3AI, MseI, HhaI, and KpnI, all PCR‐products from EY‐group phytoplasmas examined had similar RFLP profiles. When the same ribosomal DNA fragments were digested with TaqI restriction endonuclease, three different restriction profiles were detected among the EY‐group phytoplasmas. These profiles represented, respectively, (1) the EY phytoplasma (2) the phytoplasmas causing rubus stunt and being associated with alder yellows, spartium witches broom, and eucalyptus little leaf, and (3) the flavescence dorée phytoplasma. RFLP analysis using TaqI endonuclease enabled for the first time the differentiation of the phytoplasmas associated with alder yellows, eucalyptus little leaf, and spartium witches broom from the EY agent.
Resinicium bicolor; a potential biological control agent for Heterobasidion annosum
Authors: Holmer L. , Stenlid J.
Published: June 2007

After introductory competition tests in the laboratory, Resinicium bicolor was used as a potential control agent for the conifer root rot fungus Heterobasidion annosum. Greenhouse pathogenicity tests with R. bicolor on 4‐year‐old seedlings of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) showed moderate incidence of infection. In three places in Sweden, four test areas were chosen for field experiments in first‐rotation plantations and also in old forest sites of Norway spruce. Wood blocks, pre‐inoculated with one strain of R. bicolor, were buried in the soil beside stumps at 0, 1, 2, 3 and 4 months after thinning using various spatial designs. In two of the test areas, half of the stumps were treated with a suspension of H. annosum conidia from one strain by surface spraying. After 2–3 years, stump roots were investigated and the length of growth of both species were noted. The identity of mycelia reisolated from and wood debris in the test areas were confirmed by somatic compatibility tests with the original strains. The strain of R. bicolor released was recovered from all over the test area; the released H. annosum strain was only reisolated from the conidia sprayed stump roots. R. bicolor had little effect on the growth and occurrence of H. annosum. Potential control of disease spread may arise, however, from occlusion of the pathogen from outer parts of roots.
Dry weight loss of wood after the inoculation of Scots pine stumps with Phlebiopsis gigantea
Authors: Sierota Z. H.
Published: June 2007

Artificial inoculation of stumps with Phlebiopsis gigantea (preparation‘PgIBL’) against Heterobasidion annosum in Scots pine (Pinus sylvestris) stands on former agricultural lands in Poland is being performed throughout the year. The practical efficiency of the biological control appears to be influenced by the moisture content in stumps and roots. In experiment 1, dry weight loss of wood 3 months and 6 months after P. gigantea inoculation in laboratory was investigated in the stumps after salvage cutting (felling of dead and dying trees) and after thinning (routine cutting of trees) and compared with the decay of the artificially inoculated stumps under field conditions. It was found that 6 months after inoculation the dry weight loss of the samples was about 3%, 17% and 22%, respectively. In experiment 2, the decay of wood from horizontal roots collected after thinning, inoculated with P. gigantea in laboratory, was evaluated. Three months after the inoculation, the loss of dry weight wood was about 22–52%, depending on initial moisture of the roots.