Showing papers in "Forest Pathology in 1984"
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TL;DR: Survey of Eucalyptus nurseries in Kerala State indicates that the most prevalent diseases are damping-off, web blight and seedling blight in seedbeds and stem canker, leaf and shoot blights and Phaeoseptoria leaf spot in container plants.
Abstract: Survey of Eucalyptus (E, grandis and E. tereticornis) nurseries in Kerala State indicates that the most prevalent diseases are damping-off, web blight and seedling blight in seedbeds and stem canker, leaf and shoot blights and Phaeoseptoria leaf spot in container plants. Cylindrocladium spp., Rbizoctonia solani and Pythium spp. arc the main serious pathogens. Pythium myriotylum, P. deliense, R. scilani, Cylindrocladium camellias, C. clavatum and Sclerotium rolfsii are recorded for the first time on Eucalyptus.
52 citations
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TL;DR: Cytological injuries in needles of Scots pine and Norway spruce were studied at light and electron microscope level in northern Finland in relation to the severe climate and growth response of the trees.
Abstract: Cytological injuries in needles of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.] were studied at light and electron microscope level in northern Finland. Needle samples were taken from fertilized (mainly with nitrogen) and nonfertilized trees during winter 1980. The results are discussed in relation to the severe climate and growth response of the trees.
46 citations
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TL;DR: It has been hypothesised that air pollution is dimaging the needles resulting in less photosynthate and that the reduction of active mycorrhizae is due to such an initial weakening of the tree.
Abstract: Fine root studies in two old growth spruce forests affected by “Wadsterben” in Bavaria. Fine roots of healthy and declining Norway spruce (Picea abies) were investigated. We observed fewer active myeorrhizac associated with affected spruce in two old growth Forests. It has been hypothesised that air pollution is dimaging the needles resulting in less photosynthate and that the reduction of active mycorrhizae is due to such an initial weakening of the tree.
35 citations
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TL;DR: Gremmeniella abietina infects shoots of red and Scots pines through stomata on bracts that subtend short shoots and sparsely colonizes bract tissue by late summer or fall.
Abstract: Gremmeniella abietina infects shoots of red and Scots pines through stomata on bracts that subtend short shoots. The germ tube penetrates between guard cells and sparsely colonizes bract tissue by late summer or fall. Only after about late January or early February of the following year does the fungus extend from the bract and begin colonization of the short shoot and surrounding cortical tissue.
33 citations
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TL;DR: In the majority of roots which exhibited secondary structure, lesion shape reflected the pattern of periderm development, and invasion of the phloem was halted within the first 8 weeks of infection.
Abstract: Phytophthora cinnamomi Rands invaded phloem tissue preferentially in Eucalyptus marginata Sm. (Jarrah) roots of both primary and secondary structure. Rate of fungal growth in the “primary” roots was less than in roots with secondary thickening. In the main field study jarrah roots between 1.5–2.5 mm in diameter, were inoculated with P. cinnamomi at regular intervals, over 12 months and in most cases invasion of the phloem was halted within the first 8 weeks of infection. In the majority of roots which exhibited secondary structure, lesion shape reflected the pattern of periderm development. Some lesions were peripheral in the outer phloem as cylindrical periderms had formed close to the vascular cambium. Other lesions were limited to a sector of the roots; periderm had formed radially through the secondary phloem and a zone of suberization was often continuous through the cambial zone and xylem. Formation of periderm at the edge of lesions was a multi-step process with various changes occurring, including lignification and suberization of walls and accumulation of autofluorescent compounds in cell walls and vacuoles. The layers of suberized and lignified cells formed near lesion fronts, were necrophylactic periderms. Necrophylactic periderm formation generally preceded the establishment of periderm of the exophylactic type.
33 citations
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TL;DR: No evidence was found that a root pathogen is causing the deterioration in the fine root system of declining Norway spruce, and it is found that the occurrence of inactive mycorrhizae and M. r.
Abstract: From four locations in Bavaria, the only known pathogenic fungi identified from fine roots (< 2mm dia) of declining Norway spruce (Picea abics) were Cylindrocarpon destructans and Mycelium radicis atrovirens, the latter being much more common (25 vs. 95 isolations from 219 root segments). Norway spruce from six additional locations were sampled for mycorrhizae and fine roots. There were always more active mycorrhizal root tips (1.28 to 3.44 fold) on spruce which were less symptomatic of decline [P(T) = 0.0156]. However, the occurrence of inactive mycorrhizae and M. r. atrovirens were similar on all spruce that were sampled. In tins study, no evidence was found that a root pathogen is causing the deterioration in the fine root system of declining Norway spruce.
30 citations
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TL;DR: Heterobasidion annosum causes mortality and volume loss in first and second rotation pine crops and control measures include stump treatment with Peniophora gigantea and stump removal on severely diseased sites.
Abstract: Heterobasidion annosum causes mortality and volume loss in first and second rotation pine crops. Control measures include stump treatment with Peniophora gigantea and stump removal on severely diseased sites.
28 citations
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TL;DR: In spruce-wood antagonism was shown only by Hypholoma capnoides, Bjcrkandera adusta, Resinicium bicolor and Trichoderma spp.
Abstract: Investigations on biological control of Heterobasidion annosum in Norway spruce with antagonistic fungi. II. Interaction experiments in wood. Seventeen fungal species were examined for antagonism against H. annosum in wood. After inoculation of stem sections and stumps by conidia and dowels, the distribution patterns of the mycelia within the wood were recorded. In spruce-wood antagonism was shown only by Hypholoma capnoides, Bjcrkandera adusta, Resinicium bicolor and Trichoderma spp. near the site of inoculation. As the distance from this site increased H. annosum became more dominant. Inoculations by dowels yielded more infections than inoculations by spores. The patterns of myeelial distribution within the wood were similar in stem sections and in stumps. Spruce stumps were colonized naturally mainly by Resinicium bicolor, Armillaria mellea s. I. and Nectria fuckeliana. In stem sections of Pinus sylvestris, however, Phlebiopsis gigantea displaced H. annosum effectively.
27 citations
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TL;DR: Experimental proof of needle inhabiting fungi in conifers and various methods are described, which can be used to establish the presence of fungi in needles of conifer and to classify them.
Abstract: Experimental proof of needle inhabiting fungi in conifers. I. Spruce (Picea abies). Various methods are described, which can be used to establish the presence of fungi in needles of conifers and to classify them. Culture characteristics of Lophodermium piceae, L. filiforme, Rhizosphaera kalkhoffii, Thysanophora penicillioides and Tiarosporella parca arc given.
23 citations
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TL;DR: Experiments with clean air and ambient air chambers show that air pollution is a predominant factor influencing the development of the aphid population in Verburnum opulus L.
Abstract: Viburnum opulus L. is significantly more infested by Aphis fabae Scop, in the vicinity of a frequented motorway. Experiments with clean air and ambient air chambers show that air pollution is a predominant factor influencing the development of the aphid population.
21 citations
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TL;DR: Investigation of bark sections obtained from behind cankers naturally induced by Nectria coccinea var.
Abstract: The amount of total extractable phenols was determined for bark sections obtained from behind cankers naturally induced by Nectria coccinea var. faginata and from behind mechanically inflicted wounds on stems of American beech. Healthy bark from susceptible trees was found to contain a similar level of phenolics as bark from trees determined to be resistant to the beech bark disease. Six months after wounding, wound-altered bark from susceptible trees was found to be lower in phenols than woundaltered bark from resistant trees. Inoculation of wounds with N. coccinea var. faginata resulted in decreased phenolic levels in bark sections nearest the wound surface, and increased phenolic levels in sections nearest the vascular cambium, several mm distant. Phenolic levels in injured or infected bark appear to follow similar patterns as those resulting from injury or infection of xylem tissues.
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TL;DR: Inoculation of a range of poplar species and clones with conidia of Marssonina species in the laboratory resulted in the identification of two formae speciales of M. brunnea, and established that M. castagnei was not specifically pathogenic to P. alba.
Abstract: Inoculation of a range of poplar species and clones with conidia of Marssonina species in the laboratory resulted in the identification of two formae speciales of M. brunnea, and established that M. castagnei was not specifically pathogenic to P. alba. Poplars infected with M. brunnea, M. castagnei and M. populi exhibited an overlapping range of symptoms, varying from discrete spots to blotches. The dendritic lesion symptom was peculiar to M. populi and was host specific.
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TL;DR: Wetwood taken from euramerican hybrid poplars generally contained large and diverse populations of bacteria, and the bacteria most consistently associated with wetwood were identified as Enterobacter and Clostridium species.
Abstract: Wetwood taken from euramerican hybrid poplars (Populus×euramericana) generally contained large and diverse populations of bacteria. The distribution of bacteria within tissues was discontinuous in both radial and axial directions. Most of the common bacterial strains were capable of altering wood components. The bacteria most consistently associated with wetwood were identified as Enterobacter and Clostridium species. The Enterobacter was hemicllulolytic and one Clostridium strain could degrade pectin in anaerobic conditions. These bacteria may play an important rote in the development of wetwood in poplar.
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TL;DR: Investigations on biological control of Heterobasidion annosum in Norway spruce with antagonistic fungi with antagonism showed viable spores, antagonism was shown, and viable spores were produced by 17 isolates.
Abstract: Investigations on biological control of Heterobasidion annosum in Norway spruce (Picea abies H. Karst.) with antagonistic fungi. I. Production of inoculum and interaction experiments in vitro. Thirty isolates of 22 fungal species were examined in vitro for sporulation, for germination of the spores, and for antagonism of mycelia against three strains of H. annosum. Viable spores were produced by 17 isolates, antagonism was shown by 28 isolates.
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TL;DR: In this article, the CO2 uptake of European conifers increases during needle maturation, and extensive investigations with grafts of several species show that this increase may even mask a deleterious effect of a weak SO2 stress.
Abstract: This study confirms that CO2 uptake of European conifers increases during needle maturation. Extensive investigations with grafts of several species show that this increase may even mask a deleterious effect of a weak SO2 stress. In plants which are not dependent on air-borne SO2 for S nutrition CO2 uptake was not favored by SO2. Peroxidase activity of tree foliage may be a valuable stress indication, particularly in areas with light air pollution. It is, however, not specific for air pollution and seems to be most suitable for “active” monitoring.
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TL;DR: Preliminary laboratory tests support the hypothesis that slugs are important vectors in the natural spreading of the chestnut blight, complementary to other physical and biological factors.
Abstract: Slugs (Lchmannia marginata Muller) were observed moving and feeding on chestnut blight cankers in woods. Preliminary laboratory tests support the hypothesis that slugs are important vectors in the natural spreading of the blight, complementary to other physical and biological factors.
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TL;DR: Ramets of 200 clones of Cupressus sempervirens were inoculated with 6 isolates of Seiridium cardinale and significant differences were found among isolates, while there were highly significant differences among clones when length and width of canker were assumed as discriminating traits.
Abstract: Ramets of 200 clones of Cupressus sempervirens were inoculated with 6 isolates of Seiridium cardinale. No significant differences were found among isolates, while there were highly significant differences among clones when length and width of canker were assumed as discriminating traits.
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TL;DR: Critical assessments of currently available control tactics, a summary of on-going research and an account of the prospects for integrated pest management of the epidemic pine wilt disease are given.
Abstract: A review is given of historical aspects of the epidemic pine wilt disease and the associated control activities in Japan. Critical assessments of currently available control tactics, a summary of on-going research and an account of the prospects for integrated pest management of the disease are given. Research on the most appropriate application of direct control tactics are emphasized in this review, in addition to the necessity for long-term, intensive work on the environmental impact of chemicals.
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TL;DR: Peroxidase activity does not seem a suitable method in monitoring latent injury caused by low SO2 concentrations, while both short-term and long-term exposure to low concentrations of SO2 increased photo-synthesis after the exposure.
Abstract: Short-term exposure to high concentrations of SO2 caused a temporary decrease in the photosynthetic rate, while both short-term and long-term exposure to low concentrations of SO2 increased photo-synthesis after the exposure. Low SO2 concentrations did not cause any change in peroxidase activity. Thus peroxidase activity does not seem a suitable method in monitoring latent injury caused by low SO2 concentrations.
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TL;DR: Fumigation experiments with SO2 and ozone on young spruces showed increased necrosis with increase in ozone or SO2 fumigation, and peroxidase activity increased without obvious injury after SO2 treatment.
Abstract: Fumigation experiments with SO2 and ozone on young spruces. Needles of 5 year old Picea abies showed increased necrosis with increase in ozone or SO2 fumigation. Peroxidase activity increased without obvious injury after SO2 treatment. Soluble sulfhydril compounds were most suitable for detecting SO2 treatments. SO2-ozone mixture produced an effect greater than SO2 or ozone alone.
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TL;DR: This short report as a part of a broad work describes the isolation, the biological activity and the measurement of concentration of p-hydroxy acetophenone and its O-gluco-side (picein) by gas chromatography.
Abstract: This short report as a part of a broad work (Eur. J. For. Path. 15, 1985a) describes the isolation, the biological activity and the measurement of concentration of p-hydroxy acetophenone and its O-gluco-side (picein) by gas chromatography. p-hydroxy acetophenone was found to be phytotoxic to the 2-year-old saplings at a conc. of 500 ppm. The gas chromatographic measurement of p-hydroxy aceto-phenone (p-HAP) and its O-glucoside (after enzymic hydrolysis) in the current year's shoot parts showed the ratio p-HAP: p-HAP-O-glucoside always larger than 1 in the affected trees and less than 1 in the healthy trees.
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TL;DR: The inhibition of 14C-transport from needles to roots following SO2 fumigation was stronger than the reduction in I4CO2 uptake, and the changes were more marked in the SO2-sensitivc plants than in the more tolerant ones.
Abstract: The influence of SO2 on the metabolism of SO2-tolerant and SO2-sensitive seedlings of Scots pine was investigated. Under the influence of SO2 changes were observed in 14CO2 assimilation, in 14C-fixation pattern and in 14C-translocation. The changes were more marked in the SO2-sensitivc plants than in the more tolerant ones. The inhibition of 14C-transport from needles to roots following SO2 fumigation was stronger than the reduction in I4CO2 uptake.
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TL;DR: Seven clones of hybrid poplar, with parents from among four sections of the genus Populus, were potted in five Iowan soils and after a year they were sampled for mycorrhizae and endogonaceous spores, indicating indications of differences in mycotrophy among the sections.
Abstract: Seven clones of hybrid poplar, with parents from among four sections of the genus Populus, were potted in five Iowan soils. After a year they were sampled for mycorrhizae and endogonaceous spores. Eight species of Endogonaceae were recorded, seven known to form endomycorrhizae. Two ectomycorrhizal fungi, Ccnococcum geophilum and an unidentified species were noted. One poplar clone had fewer replicates in which Glomus fasciculatum spores were found, but otherwise there were no differences among the poplars in presence of spores. A soil from a P. grandidentata woodland had fewer pots with G. mosseae spores, while an agricultural soil had more occurrences of Gigaspora gigantea than other soils. No other significant differences among spores were noted for soils. Vesicles of endomycorrhizae occurred in all clones, but one was colonized more sparsely than the others. Two clones had ecto- and ectendo-mycorrhizae, two types of the former being recorded. One of these clones had significantly more C. geophilum colonization than the other. There were indications of differences in mycotrophy among the sections of the genus Populus.
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TL;DR: Differential resistance of the two leaf surfaces of mature leaves of P. candicans was attributed to the strong cutinisation of the epidermal cell wall of the highly resistant adaxial surface, and hyphae penetrated cell walls ot soft expanding leaves more readily than cell walls of mature Leaves.
Abstract: Leaf age was a significant (P < 0.05) factor in the resistance of poplar cultivars to M. brunnea. Leaf surface (adaxial/abaxial) was not a significant factor for P. nigra, P. deltoides and P. ×euramericana but was for several miscellaneous cultivars. There was no significant correlation between stomatal frequency and M., brnnnca infection level. Ultrastructural studies showed hyphae penetrated cell walls ot soft expanding leaves more readily than cell walls of mature leaves. The higher resistance of mature leaves was thus attributed to differences in cell wall ultrastructure. Differential resistance of the two leaf surfaces of mature leaves of P. candicans was attributed to the strong cutinisation of the epidermal cell wall of the highly resistant adaxial surface.
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TL;DR: Resistance is the cornerstone of management of diseases of poplar and requires the concerted employment of proper site, selection, silvicultural practices and sometimes direct or chemical control.
Abstract: Resistance is the cornerstone of management of diseases of poplar. Maximization of its effectiveness requires the concerted employment of proper site, selection, silvicultural practices and sometimes direct or chemical control.
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TL;DR: On comparable soils, stands with Picea abies and P, abies mixed with other tree species were analysed for butt rot and the percentage of butt rot in P. abies was about the same as in pure stands.
Abstract: Butt rot of Picea abies in pure and in mixed stands. On comparable soils, stands with Picea abies and P, abies mixed with other tree species were analysed for butt rot. In mixed stands the percentage of butt rot in P. abies was about the same as in pure stands.
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TL;DR: Comparisons of transpiration, photosynthesis and osmotic potential of various twigs of a healthy and a diseased fir are included to discuss possible causes for registered differences.
Abstract: The present study comprises comparative investigations of transpiration, photosynthesis and osmotic potential of various twigs of a healthy and a diseased fir. Possible causes for the registered differences are discussed.
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TL;DR: Subcortical mats of Ceratoeystis fagacearum were found to become readily overgrown by Pesotum piceae, which is likely to contribute to the low efficiency of oak wilt transmissions.
Abstract: Subcortical mats of Ceratocystis fagacearum were found to become readily overgrown by Pesotum piceae Thus by reducing the chance of contamination of insect vectors with spores of the pathogen P piceae is likely to contribute to the low efficiency of oak wilt transmissions
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TL;DR: Results show that starch reserves were related to canker size and therefore may play a role in the tree's ability to respond to infection.
Abstract: Chestnut trees (Castanca dentata) were wounded in May and inoculated with Cryphonectria parasitica. In August, canker area was measured and the surfaces of longitudinal dissections of stem wood were stained with I2KI to reveal the presence of starch. Sections with the most starch had smaller cankers than sections with no starch. Results show that starch reserves were related to canker size and therefore may play a role in the tree's ability to respond to infection.
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TL;DR: Gremmeniella abietina was able to survive in vitro for four weeks at average temperatures less than 30° C, and at higher temperatures, survival time was inversely proportional to temperature.
Abstract: Gremmeniella abietina was able to survive in vitro for four weeks at average temperatures less than 30° C. At higher temperatures, survival time was inversely proportional to temperature. The fungus survived for 23–28 months inside asymptomatic trees. Freezing, or freezing and thawing, of inoculated trees, may have promoted symptom development.