bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesure de la couleur CIELAB des aiguilles D'épicea (Picea abies [L.] Karst.) pour suivre l'action des polluants atmosphériques, dans le cadre d'un dispositif expérimental de pollution controlée Evaluation du jaunissement des aiguilles à l'aide des paramètres de couleur L*, a*, b*, C*, h*, et de la transformée de fourier des courbes de réflectance
Authors: Janin G. , Flot J. L. , Ory J. M. , Garrec J. P. , Rose C.
Published: June 2007

Measurement of the CIELAB colour variations of the Norway spruce needles [Picea abies (L.) Karst.] to detect the action of the air pollutants, in the experimental open‐top chambers of monitored pollution. Evaluation of the spruce needles yellowishness by the mean of the colours parameters (L*, a*, b*, C*, h*), and the Fourier transformation of the reflectance curves.The colour parameters of the yellowishness of spruce needles observed during the experiments in open‐top chambers with the controlled pollution can be measured quantitatively by mean of the CIELAB system L*, a*, b*, C*, h, parameters. The study of the reflectance curves in the fourier transformation provides also significant coefficients of the colour differences. Three different provenances of the spruce, 5‐year‐old, shows great differences in saturation (C*), and hue angle (h).
Pollenkeimung unter Einfluß elektromagnetischer Wellen und Felder
Authors: Krug Elke
Published: June 2007

Pollen germination of Norway spruce and Scots pine is stimulated by low doses of x‐rays and radar (densities 2,7–6 mW/m2) when exposed for one minute. Longer exposition inhibited germination generally, but the less vital pollen seemed to be destroyed first. Radiowaves with λ= 3m and electrostatic fields (frequency 50 Hz; field intensities between 2 kV/m and 10 kV/m) did not show effects on germinating pollen. Pollen tubes were longer when germinated in darkness.
Comparaison de deux méthodes d'identification des clones chèz le Basidiomycete parasite Armillaria obscura (syn: A. ostoyae)
Authors: Guillaumin J. J. , Berthelay Suzanne
Published: June 2007

Two methods were compared intending to distinguish between the clones of the root‐rot fungusArmillaria obscura(syn.Armillaria ostoyae) in nature: one based on the pairing of the diploid isolates in pure culture, the other using the incompatibility alleles as genetic markers. AsA. obscurafruits easily in vitro, both methods could be used for any type of diploid isolate whatever its origin.

The two methods were quite superposable and defined the same clones. Artificial diploids issuing from the same fruitbody and isogenic for the incompatibility alleles appeared to belong to the same clone in pairing tests.
Electron microscopical studies of poplar clones inoculated with Xanthomonas populi subsp. populi
Authors: Ebrahim‐Nesbat F. , Tiedemann S. von , Albrecht S. , Heitefuss R. , Hüttermann A.
Published: June 2007

Distribution of Xanthomonas populi subs, populi was studied 21 days postinoculation in highly susceptible, susceptible and tolerant poplar clones (Populus trichocarpa): Heimburger, Muhle‐Larsen and Columbia River. Bacteria were observed in the intercellular spaces of leaf trace of both clones Heimburger and Muhle‐Larsen. No bacteria were detected 21 days after inoculation (dpi) in ultrathin sections of the clone Columbia River. The direct effect of bacteria on the host cells was the expanding intercellular space of leaf traces by dissolution of the middle lamellae and cell walls, and collapse of the surrounding cells.

Sixteen weeks following the inoculation a tumour developed only at the inoculation site of the clone Muhle‐Larsen; Heimburger showed longitudinal cracks.
Diseases of Italian cypress caused by Botryodiplodia theobromae Pat.
Authors: Bruck R. I. , Solfl Z. , Ben‐Ze'ev I. S. , Zehavi A.
Published: June 2007

Botryodiplodia theobromae was identified as the causal agent of three hitherto undescribed diseases of Italian cypress, Cupressus sempervirens: (i) crown wilt, on mature trees, (ii) Botryodiplodia stem tanker, on mature trees, and (iii) seedling blight, in nursery stands.
Long lasting effects of O3 and SO2 on the sensitivity to drought in two clones of Picea abies (L.) Karst.
Authors: Dotzler Maria , Schütt P.
Published: June 2007

Rooted cuttings of two Picea abies‐clones were fumigated with O3 and O3+ SO2 for 12 weeks. After 4 and 16 months without fumigation the treated plants showed much higher sensitivity to drought (expressed in osmotic potential of cell sap and in percent survival) than the untreated ones.
Quantification of Armillaria rhizomorphs in Wisconsin aspen sucker stands
Authors: Stanosz G. R. , Patton R. F.
Published: June 2007

Weights of rhizomorphs of undetermined Armillaria sp. obtained using ring‐trench and core soil sampling methods around aspen stumps in stands at different intervals after harvest were correlated. The core method was used to sample a second series of stands twice (at an interval of two growing seasons) at radial distances of 0.5, 1.0, and 1.5 meters from stump centers. Stands were uncut (at both samplings) or 3, 6, 9, 12, or 15 years after harvest (at the time of the initial sampling). Rhizomorphs were obtained from less than half the cores from the uncut stand, and the quantities (weights and lengths) were relatively small from both samplings. Mean numbers of soil cores yielding rhizomorphs and the mean quantities obtained generally increased as a function of the interval after harvest (and from the first to the second sampling), except for the oldest stand.
Necrotic spots induced by simulated acid rain on needles of Abies balsamea saplings
Authors: Whitney R. D. , Ip D. W.
Published: June 2007

Simulated acid rain (SAR) of pH 2.6, 3.6 and 5.6 (control) was applied to Abies balsamea (L.) Mill. saplings at 2‐week intervals for 3 years. Ambient precipitation was excluded from the trees during this period. Light to dark brown necrotic spots along the midribs of needles, 0.1 to 0.5mm in diameter and sometimes having a white center, were associated with the most acidic (pH 2.6) SAR treatment. These spots appeared over a significantly (p = 0.05) larger area of the foliage in the pH 2.6 treatment than in controls (pH 5.6). Needles that received SAR of pH 3.6 had intermediate numbers of spots. The spots persisted for at least 12/3 years after cessation of SAR application. Needle retention, needle lengths, and the occurrence of epicormic shoots and the needle rust caused by Uredinopsis longimucronata Faull were not significantly (p = 0.05) affected by the SAR treatments. Needle retention tended to be lessened by the most acidic (pH 2.6) SAR treatment. The occurrence of Lophodermium piceae (Fuckel) Höhnel needle cast was significantly lower in the middle tree sections of the pH 5.6 and 3.6 treatments than in the pH 2.6, drought and ambient treatments. Damage by naturally occurring insects was negligible, and was not related to the SAR treatments.
A very simple method for long‐term storage of fungal cultures
Authors: Delatour C.
Published: June 2007

The method is based on the capacity of many fungi to invade and survive in wood for a long time. Small standard pieces of inoculated wood are piled up in test tubes stored in cold conditions. Reisolation of the fungus is easy by picking out only one piece of wood without disturbating the whole arrangement. By this process a large number of fungi, not only basidiomycetes, can be stored over many years without any subculturing.
Zur Taxonomie und Pathogenität von Ophiostoma piceae (Münch) Syd. im Zusammenhang mit Absterbeerscheinungen in Trauben‐ und Stieleichenbeständen des mittel‐ und nordostdeutschen Diluviums
Authors: Eisenhauer D. R.
Published: June 2007

Taxonomy and pathogenicity of Ophiostoma piceae (Münch) Syd. in connection with dieback in sessile‐ and pedunculate oak stands of the Central German and the North Eastern German Diluvium Region. The loss of vitality resulting in the dying of oak forests is most probably caused by a complex of phytopathological factors. One part of this complex may be a vascular mycosis. In this connection Ophiostoma piceae (Münch) Syd. is one of the most discussed vascular fungi. Results of investigations on the variability of some morphological parameters, of cultural growth, of the pathogenicity and of the toxicity of metabolites are reported.
Pezicula canker of Quercus rubra L., caused by Pezicula cinnamomea (DC.) Sacc. I. Symptoms and pathogenesis
Authors: Kehr R.D.
Published: June 2007

Perennial cankers on trunks of Quercus rubra planted in Germany affect trees from age 30 onward. Symptoms and histopathology are presented and compared with other major causes of bark disorders on Red Oak in Europe. Infection trials with the causal agent, Pezicula cinnamomea (DC.) Sacc., are described and pathogenesis of the disease is discussed along with predisposing factors.
Etude experimentale du transport de Pinoculum de Ceratocystis fimbriata f. platani par ľeau ?une riviere
Authors: Grosclaude C. , Olivier R. , Pizzuto J.‐C. , Romiti Corinne
Published: June 2007

Dissemination of Ceratocystis fimbriata f. platani inoculum by river water. C. fimbriata was detected up to 108 m downstream from pieces of diseased plane tree placed in a fixed site in a river in Southern France. Assessment of C. fimbriata was realized by a trapping method with healthy wood.
Abscisic acid content and defense reactions in callus cultures of poplar
Authors: Hř Ib J. , Rittich B.
Published: June 2007

Callus cultures of Populus×euramericana cv. ‘NL‐B‐132’ derived from stem and leaf tissue were compared for their content of abscisic acid and defense reactions against the basidiomycete Phaeolus schweinitzii. The callus from stems showed higher ABA‐contents and a more pronounced defense reaction in comparison with leaf callus.
Effects of NO2 on hoop pine can be counteracted by SO2
Authors: Murray F. , Clarke Karen , Wilson Susan
Published: June 2007

Long intermittent exposures ofAraucaria cunninghamii to SO2 and NO2 produced complex interactions with effects on resource allocation and plant morphology. Exposure to NO2 decreased chlorophyll concentrations but increased stem diameter and shoot fresh weight, in an apparent compensatory response, altering the growth form of the tree. The effects of NO2 were counteracted by the additional presence of SO2, although SO2 alone had little effect.
Differences in susceptibility of Eucalyptus species to Phaeoseptoria eucalypti
Authors: Nichol Nicola S. , Wingfield M. J. , Swart W. J.
Published: June 2007

Four different Eucalyptus species trials, in Natal province, South Africa, were rated for susceptibility to Phaeoseptoria eucalypti. All species found to be susceptible to P. eucalypti belonged to the subgenus Symphyomyrtus. In contrast, species belonging to the subgenus Monocalyptus were resistant to P. eucalypti. Trials at Gowan Brae and Sutton indicated that E. tereticornis and E. camaldulensis were relatively more susceptible than other Eucalyptus species. E: grandis, E. botryoides and E. saligna were found to be the most susceptible species to P. eucalypti at Bloemendal and Seven Oaks.
Ermittlung und Bewertung quantitativer Virusresistenz von Pappeln nach Inokulation mit Pappelmosaik‐Virus (poplar mosaic virus, PopMV)
Authors: Von Kontzog H.‐G. , Ebrahim‐Nesbat F.
Published: June 2007

Determination and evaluation of quantitative virus resistance in poplars inoculated with poplar mosaic virus (PopMV). Statistical analysis of data on symptom severity and virus concentration in PopMV‐infected leaves were used to determine differences in virus resistance among poplar clones. These differences were confirmed in ultrastructural studies.
Studies of the life cycle of Gremmeniella abietina on Scots pine in southern Sweden
Authors: Hellgren M. , Barklund Pia
Published: June 2007

Aspects of the life cycle ofGremmeniella abietina(Lagerb.) Morelet were studied from 1988 to 1990 in stands ofPinus sylvestrisL., 16–32 years old, in southern Sweden, initiated in 1988 with a widespread outbreak of the disease. Pycnidia started to release conidia in late spring and apothecia began to release ascospores in summer. Latent infections could still be detected one year after their establishment by cultivation of healthy looking shoots on agar petri dishes.G. abietinaappeared to have a mainly biennal life cycle, as most spores were released two years after infection of the shoot.
Structural responses in bark to mechanical wounding and Armillaria ostoyae infection in seedlings of Pinus sylvestris
Authors: Wahlström K. T. , Johansson M.
Published: June 2007

The sequence of events leading to the restoration of an intact periderm surface in the stem bark of Pinus sylvestris following wounding and challenge with Armillaria ostoyae was determined. A sub‐erized impervious tissue (SIT) was produced outside the necrophylactic periderm (NP). Al‐though A. ostoyae initially infected wounded bark with intracelfularly growing hyphae, these died before penetrating deeply into the bark. Later, intercellularly growing rhizomorphs, which had also developed from the inoculum, penetrated the NP and infected the functional phloem/ cambial zone. Compared to the reactions in uninfected wounded bark, the A. ostoyae infection delayed the formation of NP and reduced the frequency of cells involved in lignification and in SIT, but increased the number of lignified cell layers. The rhizomorph infection reached deeper and lignification was more pronounced in defoliated seedlings than in non‐defoliated ones. The importance of structural responses in defence against A. ostoyae is discussed.
Compartmentalization response of two clones of hybrid‐poplar
Authors: Smith K. T. , Shortle W. C.
Published: June 2007

A 14‐day bioassay indicated the effectiveness of Compartmentalization evident 24 months following wounding of two clones of hybrid‐poplar. The boundary pattern adjacent to columns of wound‐initiated discoloration indicated that column boundary layer formation was not the sole determinant for the effectiveness of Compartmentalization.
Fungi associated with above‐ground portions of declining oaks (Quercus robur) in Germany
Authors: Kehr R. D. , Wulf A.
Published: June 2007

Various disease symptoms on oak (Quercus robur L.) affected by oak decline in northern Germany were examined for fungal colonization. The isolated fungi are evaluated in respect to their possible pathogenic qualities and the results are compared with those of other authors and geographic regions.
Discolouration and decay from artificial wounds in 20‐year‐old Eucalyptus regnans
Authors: White D. A. , Kile G. A.
Published: June 2007

The spatial arrangement of discolouration and decay from artificial wounds in Eucalyptus regnans was consistent with the CODIT model of shigo and marx (1977) up to 2 years after wounding. Discolouration and decay had spread more from wounds which remained bark‐covered than from those where the bark was removed from the bole.
In vitro antagonism by Ulocladium botrytis of Phellinus weirii, Heterobasidion annosum, and Armillaria ostoyae
Authors: Reaves J. L. , Crawford R. H.
Published: June 2007

In Vitroantagonism of three root‐disease pathogens,Phellinus weirii, Heterobasidion annosum, andArmillaria ostoyaebyUlocladium botrytis(Preuss) is discussed. On solid medium, areas of inhibition were characteristic of antagonism, whereas, in liquid medium, antagonism resulted in the reduction of the colony dry weights of the pathogens. The antagonistic effect ofU. botrytiswas fungistatic.
Geographical distribution of the Armillaria species in The Netherlands in relation to soil type and hosts
Authors: Termorshuizen A. J. , Arnolds E. J. M.
Published: June 2007

The geographical distribution of the annulate Armillaria species was studied in The Netherlands during the period 1983–1992. Armillaria gallica (incl. A. cepistipes), A. mellea and A. ostoyae appear to be widespread, the first two species being rather common on broad‐leaved hosts growing on clay and loess soils, and the third species common on both broad‐leaved and coniferous hosts on acid sandy soils. The distribution of the Armillaria species encountered was primarily determined by soil type. From a silvicultural point of view, A. ostoyae is the most important species, being pathogenic and occurring most frequently on sandy soils, the soil type predominantly used for forestry in The Netherlands.
Variation and heritability of resistance of lodgepole pine to Western gall rust
Authors: Kojwang H. O.
Published: June 2007

Families of pine seedlings from 40 open‐pollinated trees (mother trees) from the interior of British Columbia (B. C.) were inoculated with two spore mixtures, one from the coast and the other from the interior of B. C. The relative susceptibilities of the 40 families to each spore mixture was assessed and narrow sense heritability with respect to disease resistance was estimated. The results are presented and discussed.
Ethylene production during symptom development of pine‐wilt disease
Authors: Fukuda K. , Hogetsu T. , Suzuki K.
Published: June 2007

Ethylene release from Pinus thunbergii Parl. seedlings was examined after inoculation with virulent and avirulent isolates of Bursaphelenchus xylophilus. Enhanced ethylene release was observed only in seedlings inoculated with the virulent isolate. The avirulent isolate induced necrosis of xylem ray cells and embolism in some tracheids, however, the cambium and outermost xylem was intact where water conduction was maintained. The ethylene increase coincided with cambial death in seedlings inoculated with the virulent isolate.
Soil solarization in an Italian forest nursery
Authors: Annesi T. , Motta E.
Published: June 2007

A 2‐year field and laboratory study on double‐layer solarization in a forest nursery was carried out. The efficacy of controlling soil‐borne Pythium spp., Fusarium spp. and Rhizoctonia solani is discussed.
Detection of MLOs in declining alder trees in Southern Italy and their characterization by RFLP analysis
Authors: Marcone C. , Firrao G. , Ragozzino A. , Locci R.
Published: June 2007

Mycoplasma‐like organisms (MLOs) were detected and characterized by RFLP analysis in declining trees of Alnus glutinosa and A. cordata in Southern Italy for the first time. The infected trees showed symptoms of yellowing, sparse foliage, premature autumn colouration, sprouting, deliquescent branching, phloem necrosis, dieback and witches’ brooms.
Phellinus torulosus on Cupressus sempervirens in Italy
Authors: Panconesi A. , Santini A. , Casini N.
Published: June 2007

Phellinus torulosus was reported for the first time on Cupressus sempervirens in Tuscany, Italy. This fungus causes white rot in roots and stems and may also invade and kill the cortical tissue. The invasion of trees by the fungus and its subsequent spread is probably facilitated by fire scars.
Environmental Effects on Norway Spruce Needle Wax
Authors: Günthardt‐Goerg M. S. , Keller T. , Matyssek R. , Scheidegger C.
Published: June 2007

In spring, tubular wax structures were observed on the needle surfaces of new Norway spruce needles and also on previous‐year needles. In young plants, as in mature trees, the fusing and eroding of the wax tubes on needles of increasing age had taken place in relation to their exposure, particularly to wind and precipitation. The quantity of needle wax and certain fractions of the extracted wax differed in mature trees at two field sites and in young clonal plants. No difference in wax quantity and only small differences in wax composition occurred among young plants which had undergone different treatments (fumigation with O3, SO2, ambient air, filtered air, or planting at the sites). Environmental effects on wax structure, wax quantity and the presence of certain compounds in the wax were identified.
Shoot dieback of lodgepole pine in Scotland caused by Ramichloridium pini
Authors: Rahman M. A. , Millar C. S. , Gibbs J. N.
Published: June 2007

Research conducted on shoot dieback of lodgepole pine, Pinus contorta, during the early 1980's in west Scotland is summarised. The dieback symptoms and their stages of development are described. Ramichloridium pini de Hoog and Rahman was regularly isolated from bark and xylem tissue of dieased shoots. Artificial inoculations established that this fungus was the cause of the disease.
A selective medium for Phellinus noxins
Authors: Chang Tun Tschu
Published: June 2007

A selective medium was developed for isolation of Phellinus noxius. The medium consists of 20 g/l malt‐extract, 20 g/l agar, 10 mg/l benomyl, 10 mg/l dicloran, 100 mg/l ampicillin and 500 mg/1 gallic acid. For isolation of P. noxius from soils, 1000 mg/l tergitol NP‐7 was added to restrict the size of individual colonies. Comparisons of this selective medium with other media selective for isolation of hymenomycetes showed that the former was more effective for isolation of P. noxius.
Pseudomonas syringae. pv.morsprunorum on wild cherry for timber production: outbreak and field susceptibility
Authors: Scortichini M. , Biocca M. , Rossi M. P.
Published: June 2007

In central Italy, Pseudomonas syringae pv. morsprunorum was isolated from wild cherries (Pranus avium) that had been planted for timber production. Biochemical tests were consistent with those characterizing the pathovar. Pathogenicity tests yielded necrotic lesions, shot holes on the leaves and decoloration of the tissues beneath the twig periderm, but no symptoms on inoculated lilac and pear leaves. In addition, whole‐cell protein profiles of the isolates and reference strains were remarkably homogenous when analysed by cluster analysis. All isolates were negative in ice‐nucleation activity and in antifungal‐compound production. The main symptoms observed in the field were cankers on twigs, branches and trunks, as well as withering of the shoots. Evalution of the field susceptibility of 18 clones indicated that the following selections must be considered susceptible to the pathogen: Montemignaio, Piantata Catenaia, Puzzolo, Raggiolo, Pozzacce 2, Pozzacce I, Paradision. Alpe 2 seems to be less susceptible.
Formation of the ligno‐suberized barrier zone and wound periderm in four species of European broad‐leaved trees
Authors: Woodward S. , Pocock S.
Published: June 2007

The development of wound periderm after mechanical wounding was examined in the barks of Acer pseudoplatanus, Betula pendula, Fagus sylvatica and Sorbus aucuparia. Following the initial necrosis of cells immediately surrounding the wounds, development of the ligno‐suberized barrier zone was detected within 7 days. Suberin deposition was observed in this tissue in A. pseudoplatanus, S. aucuparia and B. pendula 7 days after wounding, but not in F. sylvatica until day 14. By 28 days after wounding, extensive thickening of the walls of these cells had occurred. Differentiation of the wound periderm was detected immediately abutting the ligno‐suberized barrier‐zone tissues in all species, with extensive development by 28 days. Fifty‐six days after wounding, the wound periderm was fully formed and completely confluent with the original periderm. Development of the wound response was similar in all species, with differences only in the timing of first detection of suberin.
Gremmeniella‐infected Pinus contorta as raw material in the production of kraft pulp
Authors: Ahlqvist B. , Karlman M. , Witzell J.
Published: June 2007

Pinus contorta, logs with occluded cankers caused by the pathogen Gremmeniella abietina, as well as logs from unaffected trees were sampled from a 23‐year‐old plantation in Sweden and compared in terms of their paper properties. Damaged wood gave kraft pulp with poor paper properties: it required a larger amount of beating energy and resulted in paper with low tear strength, air permeability, tensile stiffness, burst strength, and poor light‐scattering properties. However, small amounts of damaged wood mixed in with a large amount of healthy wood can pass almost unnoticed. The use of trees with a larger content of damaged wood will lead to serious processing problems and give a pulp with poor paper properties. Thus, wood damaged by Gremmeniella should be sorted out and classed as low‐grade raw material.
Susceptibility of the Quercus rubra root system to Phytophthora cinnamomi; comparison with chestnut and other oak species
Authors: Marĉais B. , Dupuis F. , Desprez‐Loustau M. L.
Published: June 2007

The susceptibility of oak seedlings (Quercus palustris, Quercus robur, Quercus rubra) and chestnut seedlings (Castanea sativa) to Phytophthora cinnamomi was tested. The dynamics of infection was examined in plant material raised in a rhizotron. In the oak species, primary root tissues were susceptible whereas secondary cortical tissues showed some resistance to P. cinnamomi. Secondary cortical tissues of the tap root in C. sativa were susceptible. Inoculations with P. cinnamomi were performed both in situ and on excised roots of mature Q. rubra. In both cases, the resistance of Q. rubra roots and shoots was negatively correlated with diameter at the inoculation point. Small roots (l–5‐cm diameter) were resistant, whereas collar and trunk were susceptible. In contrast to oak, small excised roots of mature C. sativa (0.7–2‐cm diameter) were susceptible to P. cinnamomi. This may explain why P. cinnamomi does not induce a decline of the attacked oaks, but rather a trunk canker.
Antagonism of Acremonium mucronatum towards Diplodia mutila in tests in vitro and in situ
Authors: Ragazzi A. , Moricca S. , Vagniluca S. , Dellavalle I.
Published: June 2007

Tests in vitro and in situ showed that both mycelial and conidial suspensions of Acremonium mucronatum were antagonistic for Diplodia mutila, a common pathogen on the apical twigs of declining Quercus cerris, Quercus frainetto, Quercus pubescens and Quercus robur. Antagonism was greater with the mycelium than with the conidial suspensions, and was strongest at a test temperature of 20°C. The results suggest that pathogenicity of D. mutila on declining trees may be significantly reduced by the presence of A. mucronatum.
Influence of clonal susceptibility, leaf age and inoculum density on infections by Melampsora larici‐populina races E1 and E3
Authors: Giorcelli A. , Vietto L. , Anselmi N. , Gennaro M.
Published: June 2007

A study was conducted on the influence of clonal susceptibility, leaf age and inoculum density on the incubation and presporulation periods, and on the intensity of attack of Melampsora larici‐populina races El and E3, under controlled conditions, on artificially inoculated poplar leaf discs. Both races were more virulent on susceptible clones and on 5‐ to 15‐day‐old leaves. On susceptible clones the intensity of attack increased progressively with the increase of inoculum density. Where there was complete coverage of the leaf surface, uredia were smaller in size as a result of the increase in density. The incubation period and, above all, the average presporulation period of susceptible clones proved to be longer with 1‐ to 3‐day‐old leaves and, generally, with the oldest. The epidemiological consequences of these results are discussed.
Characterization of Canadian isolates of Chondrostereum purpureum by protein content, API ZYM and isozyme analyses
Authors: Shamoun S. F. , Wall R. E.
Published: June 2007

Seventeen isolates of Chondrostereum purpureum, collected from New Brunswick, Vancouver Island, and south‐eastern British Columbia, Canada, were compared to determine the degree of genetic variation among isolates from different host species and different biogeographic locations. Several characteristics, including mycelial protein content, fungal biomass, API ZYM profile (semi‐quantitative assay to detect the presence of 19 different enzymatic activities in an organism), and isozyme patterns were measured in these isolates. All 17 isolates shared similar API ZYM profiles, with only minor variation observed in the level of expression of specific enzymes. Of the 13 isozyme systems examined, eight (acid phosphatase, alkaline phosphatase, β‐esterase, β‐glucosidase, malate dehydrogenase, peroxidase, phosphoglucomutase, and polyphenoloxidase) produced measurable activity. No qualitative differences were observed between the isolates for all of these enzymes. There appeared to be limited variation between the isolates collected from across Canada and there was no correlation between specific API ZYM, and isozyme patterns and either host plant or geographical source of the isolates.
Detection of phytoplasma infections in declining Populus nigra ‘Italica’ trees and molecular differentiation of the aster yellows phytoplasmas identified in various Populus species
Authors: Berges R. , Cousin M.‐T. , Roux J. , Mäurer R. , Seemüller E.
Published: June 2007

A disease of Populus nigra‘Italica’ associated with foliar yellowing, sparse foliage, stunting, dieback, and decline was observed in south‐western Germany; a witches’ broom disease of Populus alba that is known in other countries was also detected in Hungary and Germany. The aetiology of the diseases was studied by fluorescence microscopy and polymerase chain reaction (PCR) amplification. Using fluorescence microscopy, phytoplasmas could be detected only in P. alba. However, most diseased trees of P. nigra‘Italica’ tested phytoplasma‐positive by PCR. In some of the trees the phytoplasma numbers were so low that nested PCR was required to detect the infection. Very low phytoplasma numbers were also observed in diseased Populus tremula. The identity of phytoplasmas from P. nigra‘Italica’ sampled in Germany and France, P. alba and also P. tremula was examined by restriction fragment length polymorphism (RFLP) analysis of PCR‐amplified ribosomal DNA. In all poplars, phytoplasmas of the aster yellows group were detected. However, three different RFLP groups were identified that consisted of (1) French strains from P. nigra‘Italica’, (2) German strains from P. nigra‘Italica’ and (3) strains from P. alba and P. tremula. The profile observed in the last group was probably the result of sequence heterogeneity in the two 16S RNA genes.
First report of Sphaeropsis canker on cypress in South Africa
Authors: Linde C. , Kemp G. H. J. , Wingfield M. J.
Published: June 2007

In this study a Sphaeropsis sp. is recorded as causing cankers on cypress in South Africa. These cankers are either found alone or on trees which are infected with the well‐known cypress canker pathogen, Seiridium unicorne. When the two fungi occurred together, lesions could not be distinguished from each other, although the greater number of lesions were caused by the Sphaeropsis sp. The fungus appears to be identical to that described as Sphaeropsis sapinea f.sp. cupressi, in Israel, which is a fungus very different from the pine pathogen, Sphaeropsis sapinea. Pathogenicity tests showed that the Sphaeropsis sp. is significantly more pathogenic to Cupressus lusitanica than to Pinus roxburgii and Pinus elliottii. S. sapinea was pathogenic only to the Pinus spp. tested, and not to C. lusitanica. In contrast, the cypress pathogen Seiridium unicorne, was pathogenic to C. lusitanica and also to the two Pinus spp. tested.
Histological and histochemical detection of defence responses in pine embryos challenged in vitro with Heterobasidion annosum
Authors: Nsolomo V. R. , Woodward S.
Published: June 2007

Embryos of Pinus sylvestris, Pinus nigra var. maritima and Pinus contorta were inoculated in vitro with Heterobasidion annosum and the histology and histochemistry of the host response determined. Three days after challenge, intercellular penetration of hyphae through the epidermis and into the cortex of the host species had occurred. In cells close to the invading hyphae, cell walls became thickened in all three pine species. Lignification and suberization of cell walls in the cortex was detectable in P. nigra var. maritima and P. contorta, but not in P. sylvestris. Moreover, cells in the cortex of P. nigra var. maritima and P. contorta became occluded with dense deposits staining positively for phenolic and lipidic materials. Starch grains had accumulated in host cells close to sites of penetration by day 3, and levels appeared to increase by day 6, except for tissues where heavy invasion by H. annosum had occurred. Host responses intensified between 3 and 6 days after challenge. By day 6, however, the pathogen had penetrated as far as the stele and into the developing xylem vessels. Nine days after challenge, host tissues contained abundant intra‐ and inter‐cellular hyphae, causing severe disruption and disintegration of all tissues. The utility of such in vitro systems in studies on the resistance responses of conifers to challenge with fungal pathogens is discussed.
Secondary metabolites from dual cultures of genetically different Armillaria isolates
Authors: Sonnenbichler J. , Guillaumin J.‐J. , Peipp H. , Schwarz D.
Published: June 2007

Toxic secondary metabolites are synthesized for attack or defence in competing cultures of different basidiomycete species. In combination with incompatibility reactions changes in the pattern of secondary metabolites were also detected in dual cultures of diploid isolates of different Armillaria species (Armillaria gallica, Armillaria borealis and Armillaria cepistipes) on agar. In dual cultures the response in A. cepistipes was most pronounced and occurred combined with increasing growth inhibition of the fungus. The toxic metabolites which were formed in monocultures disappeared and the newly arising metabolites showed no antibiotic activity. The chemical structures of the compounds have been elucidated (two are described for the first time) as sesquiterpene esters of orsellinic acid derivatives. The augmenting metabolites of A. cepistipes are dehydroxylation products. A new facet of the role of secondary metabolites in the ecological interactions of fungi is described, namely, the detoxification of toxins by a competitor.
Liberation of Heterobasidion annosum conidia by airflow
Authors: Möykkynen T.
Published: June 2007

The effect of speed and humidity of the airflow and the míst sprayed with airflow on the liberation of conidia of Heterobasidion annosum from pure cultures was studied in a small windtunnel. The conidia were liberated more easily in humid than in dry airflow. Liberation was most abundant when mist was added to the airflow. Threshold speed for the liberation of conidia was calculated to vary between 1.8 m/s and 3.9 m/s. According to the results, conidia of H. annosum may be liberated into the air by wind gusts associated with high humidity or mist and thus the conidia may have a role in aerial dispersal, although this is probably small compared with basidiospores.
Accumulation of airborne fluorides in forest trees and vegetation
Authors: Horntvedt R.
Published: June 2007

The accumulation of fluoride in natural vegetation exposed to emissions from five aluminium smelter plants in Norway was studied during the years 1990–93. About 2000 leaf, bark and twig samples of 60 plant species, collected mostly during the growing season, were analysed. Rowan (Sorbus aucuparia) was widespread and common in the areas studied, and was used as a reference species. Fluoride concentrations in monthly samples of rowan leaves were linearly related to fluoride exposure (average fluoride concentration in ambient air × days since leaf emergence). The accumulation coefficient for rowan was estimated to be 1.7 m3/g dry wt. day. Most other species had values between 0.3 and 1.5; the median for all species was 0.8. The fern Dryopteris filix‐mas was exceptional, containing on average three times greater fluoride concentrations man rowan. High background levels indicated that soil uptake contributed significantly to the fluoride accumulation in this species. The fluoride concentrations in bark and shoots of trees were mostly low compared with leaves, but the bark of Betula pendula and B. pubescens had very high concentrations.
Laccase isoenzyme patterns of European Armillaria species from culture filtrates and infected woody plant tissues
Authors: Robene‐Soustrade I. , Lung‐Escarmant B.
Published: June 2007

Polyacrylamide isoelectric focusing with specific staining for laccase activity was used to characterize laccase from European Armillaria species (Armillaria ostoyae, Armillaria mellea, Armillaria gallica, Armillaria cepistipes). The enzyme was extracted from culture media either supplemented, or not, with pine sawdust, and also from Pinus pinaster naturally infected by A. ostoyae, or artificially inoculated with A. mellea and A. ostoyae. Some differences in banding patterns were found for Armillana isolates according to the species and the culture media, but a common band at pI = 3.4 was found in all the extracts tested, independently of their origin (culture filtrate or wood).
Detection and partial characterization of extracellular proteases of the pathogenic fungi Endocronartium pint, Gremmeniella abietina and Heterobasidion annosum
Authors: Pappinen A. , Von Weissenberg K.
Published: June 2007

Protease activities from 10 homokaryotic isolates of Heterobasidion annosum., two isolates of Grem‐meniella abietina and six isolates of Endocronartium pini were studied. All the fungi showed in vitro protease activity with denatured casein. The greatest caseinolytic activity was at acidic pH, but Heterobasidion annosum and Gremmeniella abietina showed caseinolytic activity at basic pH also. Protease preparations from Heterobasidion annosum were able to degrade proteins from total phloem extracts of Pinus sylvestris, Picea abies, Betula pendula and Juniperus communis. At basic pH the artificial substrates hippuryl arginine (HA) and hippuryl phenylactic acid (HPLA), were hydrolysed most rapidly by Heterobasidion annosum at pH 8.1, indicating high exopeptidase activity at this pH. According to inhibitor studies with EDTA (ethylenediaminetetraacetic acid), E64 (L‐trans‐epoxy‐succinyl‐leycylamide‐(4‐guanidino)‐butane‐agmatine) and pin2 (potato trypsin/chymotrypsin inhibi‐tor) both cysteine and serine proteases were present in proteases secreted by these pathogens, although only very low protease activity at basic pH was detected with Endocronartium pini.
Development of Leptographium wageneri on root surfaces and other substrata
Authors: Diamandis S. , Epstein L. , Cobb F. W. , Popenuck T. , Hecht‐Poinar E.
Published: June 2007

Conidia of Leptographium wageneri var. ponderosum, Leptographium wageneri var. pseudotsugae and Leptographium wageneri var. wageneri germinated on wounded roots of ponderosa pine (Pinus ponderosa), Douglas fir (Pseudotsuga menziesii), and pinyon (Pinus edulis), but not on unwounded roots. On wounds, germination occurred regardless of the combination of pathogen variety and plant species. When wounded roots of ponderosa pine and Douglas fir seedlings were inoculated with conidia of L. w. var. ponderosum and L. w. var. pseudotsugae, respectively, 87‐100% of the seedlings became infected. When unwounded roots were inoculated with wooden blocks colonized with L. wageneri, 60‐66% of the seedlings became infected.

The development of L. w. var. ponderosum and L. w. var. pseudotsugae on agar was compared with their development on agar overlaid with either cellophane or Nucleopore membranes. Undulating hyphae were found commonly in and on the agar, but less frequently on the membranes. On both membranes, mycelia formed mats which were tightly appressed to the surface; mats were not formed on the agar. On both agar and the membranes, two or more hyphae often formed a strand. When L. w. var. ponderosum mycelia were allowed to colonize the surface of an unwounded pine root, strands, undulating hyphae and poorly formed mats were seen.
Intersterility groups of Heterobasidion annosum and their host specificity in Bulgaria
Authors: Porta N. La , Apostolov K. , Korhonen K.
Published: June 2007

The occurrence of 46 strains of Heterobasidion annosum from four forest areas in Bulgaria is reported. Three intersterility groups, P, S and F, were identified for the first time in populations of this pathogen in Bulgaria. A strict host specificity of different intersterility groups was observed even in mixed stands. The P group was isolated from Pinus sylvestris and Pinus nigra and occasionally from stumps of Abies alba. It was rare in artificial pine plantations on dry sites, whereas it was more common on more moist sites. The F group caused severe damage on Abies alba but was not found, even as a saprotroph, on admixed pines. This is the first report of the F group on Abies alba in the Balkans. The S group was found only on Picea abies.
Stimulation of Armillaria ostoyae vegetative growth by tryptophol and rhizomorph produced by Zygorhynchus moelleri
Authors: Kwaśna H. , Lakomy P.
Published: June 2007

Tryptophol (an indole‐3‐ethanol analogue which is a major secondary metabolite produced by Zygorhynchus moelleri) stimulated the growth of 13 out of 18 isolates of Armillaria ostoyae in culture. Rhizomorph production of 16 out of 18 isolates of A. ostoyae was enhanced by the presence of Z moelleri in oak branch segments. Tryptophol can be considered as a growth‐promoting substance stimulating the vegetative growth of A. ostoyae in culture, and Z. moelleri as a fungus stimulating the rhizomorph formation on oak wood.
Die Bedeutung von Krankheitserregern beim gegenwärtigen Eichensterben in Europa – eine Literaturübersicht
Authors: Donaubaur E.
Published: June 2007

The decline of oaks (Quercus spp.) has been reported in literature for more than two centuries. The symptoms of this syndrome seem to be the same at different sites ‐ with the exception of oak with’ in North America, the geographic range of declines coincides more or less with the natural range of oaks, but most of the reports from the past few decades deal with the European situation and less With such syndromes in America and Asia. So far, the decline of oaks is not yet fully understood. Pathogens play’ a role as predisposing and aggravating factors, but in general are not the primary cause of the decline.
Tree mortality risk of oak due to gypsy moth
Authors: Gottschalk K. W. , Colbert J. J. , Feicht D. L.
Published: June 2007

We present prediction models for estimating tree mortality resulting from gypsy moth, Lymantria dispar, defoliation in mixed oak, Quercus sp., forests. These models differ from previous work by including defoliation as a factor in the analysis. Defoliation intensity, initial tree crown condition (crown vigour), crown position, and species grouping classes were highly significant in categorical analysis of variance for mortality. Heavy defoliation intensity was shown to have a strong, consistent influence in increasing the probability of tree mortality. Classification and Regression Tree (CART) analysis, a binomial decision tree procedure, was used to develop prediction models of mortality risk for use by forest managers. The best decision tree had 65 groups that correctly classified 75% of the live trees and 76% of the dead trees. Models were run separately by defoliation class and provided correct classifications between 63 and 78% of the trees. Forest land managers can use these models to assign probabilities of death for moderate and heavy defoliation intensity levels and compare predicted mortality to mortality of undefoliated trees to determine how gypsy moth defoliation will affect their stands. The probabilities can be used to develop marking guides Lased on projected defoliation levels for implementing silvicultural treatments to minimize gypsy moth effects in forest stands prior to infestation.
The distribution of Phratora vulgatissima (Coleoptera: Chrysomelidae) on cultivated willows in Britain and Ireland
Authors: Sage R. B. , Tucker K.
Published: June 2007

Insect samples were collected from the canopy of 24 willow short rotation coppice (SRC) sites on farmland in Britain and Ireland in 1995. The blue willow beetle Phratora (= Phyllodecta) vulgatissima (L.) (Coleoptera: Chrysomelidae), previously identified as the main defoliating pest of this crop, was recorded from 13 of these at varying levels of abundance. Data describing aspects of the environment at each site were also collected. These data were used to create potential explanatory variables for a regression analysis of beetle abundance. This analysis indicated that P. vulgatissima were most likely to occur and were more abundant at older willow sites on clay soils and at sites that bad certain free‐living willow species growing nearby. Within sites, most willow clones sampled contained P. vulgatissima, although two, Salix burjatica‘Germany’ (‘Aquatica Gigantea’) and Salix mollissima‘Q83’ (Salix triandra × Salix viminalis), were avoided. Chrysomelid pest avoidance and clonal resistance could form part of an integrated pest management strategy for SRC crops.
A rapid, apple‐based test for virulence in Cryphonectria cubensis isolates
Authors: De Lange W. J. , Wingfield B. D. , Wingfield M. J.
Published: June 2007

The presence of the Eucalyptus canker pathogen Cryphonectria cubensis in South Africa is of concern to the local forestry industry. Quantification of the virulence of this fungus through the inoculation of trees, is both time consuming, and expensive. In this study, the potential to use apples in screening for virulence of isolates of C. cubensis, was tested using different apple cultivars and inoculation procedures. The best indication of virulence was given on Golden Delicious apples incubated at 25°C for 14 days. Here, the lesion size associated with inoculations of C. cubensis, was found to correlate significantly with the virulence of the isolates, as determined by inoculations on trees.
Protocol of the Caesarean Section as Performed in Daily Bovine Practice in Belgium
Authors: Kolkman I , De Vliegher S , Hoflack G , Van Aert M , Laureyns J , Lips D , De Kruif A , Opsomer G
Published: June 2007

Contents

In the early part of the 20th century, veterinarians began to perform Caesarean section (CS) in cows. At first, it was a final remedy to save the calf and/or the cow in more complicated obstetrical cases. As in Belgium, the Belgian Blue (BB) breed has become the predominant beef breed, CS are currently performed on a routine basis in daily practice. The overwhelming success of the breed is based on its hypermuscularity and exceptional carcass characteristics with high killing out (>70%). These and other characteristics made the breed popular and newborn animals valuable. Consequently, farmers do not want to take any risk of losing the calf during birth. This, together with the fact that bovine practitioners perform CS successfully on a routine basis, has made CS an elective operation. It is, however, important to remember that CS is still a major abdominal operation and that complications are not uncommon both during and after the operation. To end up with a good success rate, it is very important to follow a high‐quality and sterile surgical procedure. The current paper describes the standard protocol by which CS are performed by the veterinarians of the Ambulatory Clinic of the Department of Reproduction, Obstetrics, and Herd Health of the Faculty of Veterinary Medicine in Ghent (Belgium). The aim of the article is to provide a successful protocol as regards CS. We especially focus on those factors which are known to be limiting for the success of the surgery and highlight the most recent recommendations to optimize the outcome of the operation.