Untersuchungen zur Variabilität von Lophodermium pinastri

Studies of the variability of Lophodermium pinastri. I. Cultural Variants. Lophodermium pinastri is a variable fungus species. From its behaviour in artificial culture 3 constant, morphological main types are observed. These are described in detail. Observations on sectoring found and on reaction types between various fungus isolates are given.     

Physiologische Untersuchungen über die unterschiedliche Resistenz von Pinus sylvestris gegen Lophodermium pinastri

Physiological studies on variation in resistance of Pinus sylvestris to Lophodermium pinastri. I. Buffer capacity in needles. Studies on the buffering of hydrogen-ion concentration in needles of resistant and susceptible pines showed that the pH-value was changed by the growing fungus from about pH 3.7 to 5, The buffer capacity of homogenized needles varied greatly between clones, The change of pH-value as well as the buffer capacity were significantly different between resistant and susceptible clones.     

Experimentelle Ergebnisse bei Laborinfektionen von Kiefern mit Lophodermium pinastri Schrad

Ohne ZusammenfassungMit Unterstützung der Deutschen Forschungsgemeinschaft.     

Lophodermium pinastri in submerged culture

The growth and morphology of Lophodermium pinastri under submerged conditions is described. Submerged cultures are shown to be suitable for the laboratory screening of the effectiveness of different fungicides which may be used in forestry against Scots pine needle-cast.     

Züchtung von Reinkulturen des Pilzes Lophodermium pinastri (Schrad.) Chev. zur Entstehung von sexuellen Fruchtkörpern (Hysterothecien)

Production of hysterothecia from pure cultures of Lophodermium pinastri (Schrad.) Chev. A method is described for the production of hysterothecia from pure cultures of L. pinastri. Previously sterilized needles of Finns sylvestris, after being overgrown on the culture dish are removed and put on living moss under natural conditions. In 2–2,5 months hysterothecia appear.     

Epidémiologie du Lophodermium pinastri (Schrad.) Chev.

Epidemiology of the needle-cast fungus of pines (Lophodermium pinastri): results of four years studies with the aid of a Hirst spore trap . This study is dealing with the results of laboratory and forest (Haguenau) observations on the biology of the needle cast fungus of pines. The spores were harvested during a period of four years with a Hirst spore trap and their germination rate was studied. The results obtained permit to apply chemical treatments with a certainty of success.     

Colonization and lignin decomposition of pine needle litter by Lophodermium pinastri

The colonization and lignin decomposition of pine (Pinus thunbergii and Pinus densiflora) needle litter by an endophytic fungus, Lophodermium pinastri, was examined with field observations, a field experiment and laboratory experiments. In pine needles collected from the field, needle mass per length and lignin content were lower in needle portions bearing Lophodermium fruiting bodies than in the remaining needle portions, whereas total carbohydrate content was not different between them. Total and live hyphal lengths were greater in needle portions bearing Lophodermium fruiting bodies than in the remaining needle portions. Lophodermium fruiting bodies were not formed on sterilized needles after a 6‐month incubation on the forest floor, whereas they formed on 20% of non‐sterilized needles, indicating that this fungus can only colonize live needles on the branch. In pure culture decomposition tests, mass loss of lignin was detected for several isolates of L. pinastri, but was variable among isolates and between the needles of two pine species. A comparison of the rDNA‐internal transcribed spacer sequences between L. pinastri isolates of P. thunbergii and P. densiflora indicated that the two groups were phylogenetically separated. This study is the first to show that L. pinastri has the ability to decompose lignin in dead pine needles.     

Weitere Untersuchungen zur unterschiedlichen Anfälligkeit von Pinus nigra-Klonen gegenüber Scleroderris lagerbergii

Further studies on differing susceptibilities of Pinus nigra clones to Scleroderris lagerbergii. In a seed orchard 14 clones of Austrian black pine (Pinus nigra ssp. nigra) showed significant differences of susceptibility to Scleroderris lagerbergii. Significant clonal differences existed also in buffering capacity of homogenized bark tissue of one-year shoots. Less susceptible clones had a higher buffering capacity.     

Physiological studies on variation in resistance of Pinus sylvestris to Lophodermium pinastri

Buffering capacity and pH values of extracts of pine needles varied with age in the course of the ontogeny of needles. Significant differences between a resistant and a susceptible pine clone group in relation to resistance against Lophodermium pinastri could be shown in autumn and winter. Also the variability of the parasite influences the host-parasite interaction as shown by alteration of pH values by 3 L. pinastri strains in cultural trials on needle extract medium.     

The development of Lophodermium pinastri in conifer nurseries and plantations in North America

The recent outbreak of Lophodermium needlecast in North America first appeared in 1966 in forest nurseries on red pine (Pinus resinosa) and Scotch pine (P. sylvestris). Dispersal of infected nursery stock throughout North America has created a serious needlecast problem in Scotch pine Christmas tree plantations. Two biotypes of L. pinastri are present. The pathogenic strain may be a recent introduction. The fungicides maneb and chlorothalonil are being used for control.     

多·硫烟剂防治马尾松落针病试验初报

笔者通过采用13.0%多·硫烟剂、2.5%百菌清烟剂对马尾松落针病进行防治试验,结果表明:13.0%多·硫烟剂防治马尾松落针病的适宜用药量为1600～2000g/666.7m2,且对马尾松生态安全。     

Untersuchungen zur Bewertung von Jungpflanzen verschiedener Nadelbaumarten

Ohne ZusammenfassungDie Abhandlung enthält den ersten, stark gekürzten Teil der Dissertation des erstgenannten Verfassers, die von der Staatswirtschaftlichen Fakultät der Universität München angenommen wurde. Sie ist ergänzt und erweitert durch zusätzliche Untersuchungen und Auswertungen des zweitgenannten Verfassers. Die gesamte Dissertation kann vonH. Aksoy über das Institut für Forstsamenkunde und Pflanzenzüchtung in München 13, Amalienstr. 52, bezogen werden.     

Untersuchungen zur Cytologie und zum Wachstum verschiedener Stämme von Fomes annosus (Fr.) Cooke

Studies of cytology and growth of different strains of Fomes annosus (Fr.) Cooke. I. Numbers of nuclei and DNA content in different isolations and stages of development. In cytological and cytophotometric studies, determinations were made of nuclear numbers and DNA contents of both conidia and basidiospores, of the primary mycelium and of mycelium after plasmogamy. Information was also obtained on parasexual phenomena in dikaryotic mycelium which can be held responsible for the great variability of the fungus.     

Weitere Beobachtungen zur Natur von Insektenviren an Hand von elektronenmikroskopischen Untersuchungen

Zusammenfassung Ausstriche viruserkrankter Fichtengespinstblattwespen (Lyda hypotrophica) und Seidenspinner (Bombyx mori) wurden in mehreren zeitlich aufeinanderfolgenden Intervallen elektronenmikroskopisch untersucht, wobei bei Lyda im zeitlichen Nacheinander Polyeder, Kapseln, winzige Korpuskeln und kolloidale Massen festgestellt werden konnten. Bei in wässeriger Lösung gehaltenen Seidenspinnerpolyedern zeigte sich eine Umbildung namentlich der Randzonen der Polyeder zu kettenförmigen Bildungen, die letzten Endes wieder in längliche kapselförmige Bildungen zerfielen.Unter Xyloleinwirkung ließen sich diese Körperchen zu Umwandlungen bringen, die auf ihren Zusammenhang hinwiesen. Bei Polyedern ließen sich unter Xyloleinfluß ähnlich wie bei den Lärchenwicklerpolyedern Spaltungserscheinungen erzielen, die gleichzeitig mit Vorgängen im Inneren der Polyeder parallel gingen, die an Stadien im Zellkern zur Zeit der Teilung der Zellen erinnerten.     

Untersuchungen zur biologischen Bekämpfung von Heterobasidion annosum an Fichte (Picea abies) mit antagonistischen Pilzen

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.     

Untersuchungen zur Pathogenität des BaumholznematodenBursaphelenchus fraudulentus Rühm

Zusammenfassung Der LaubbaumnematodeBursaphelenchus frandulentus ist eng mit dem QuarantäneschädlingB. xylophilus verwandt und kann in hoher Anzahl in toten oder absterbenden Laubbäumen gefunden werden. Um zu klären, obB. frandulentus pathogen für Laub- oder Nadelbaumarten sein kann, wurden mikroskopische Untersuchungen am Holz von mitB. frandulentus befallenen Eichen durchgeführt und Infektionsversuche im Gewächshaus mit dreijährigen Bäumen angelegt.Die Auswertung von Holzschnitten ergab, daßB. fraudulentus nur in den Tracheen vorhanden war. Es wurden keine direkten Zell- oder Gewebezerstörungen beobachtet, die auf eine Saugtätigkeit des Nematoden zurückzuführen wären. In den Tracheen waren ebenfalls Pilzhyphen vorhanden, die die Nematoden möglicherweise als Nahrungsquelle nutzen.AnQuercus robus, Fagus sylvatica undPinus sylvestris wurden Inokulationen mit 15 000B. fraudulentus/Baum durchgeführt, oder auch kombinierte Pilz-Nematoden-Inokulationen mitTrichoderma sp. oderVerticillium leptobactrum und zusätzlich jeweils 12 000B. fraudulentus/Baum. Während der elfmonatigen Versuchsdauer wurden weder durchB. fraudulentus alleine noch in Kombination mit den Pilzen Krankheitssymptome hervorgerufen. Die Bäume zeigten keine Chlorosen oder Welkesymptome und trichen im Folgejahr wieder gut aus. Aus den Bäumen der untersuchten Arten konnten nach 11 Monaten vitaleB. fraudulentus in unterschiedlicher Anzahl aus dem Holz reisoliert werden, insgesamt jedoch deutlich weniger als inokuliert wurde. Die beiden inokulierten PilzartenV. leptobactrum undTrichoderma sp. hatten keinen fördernden Einfluß auf die Vermehrung und Ausbreitung vonB. fraudulentus inQ. robur undF. sylvatica.Die Ergebnisse zeigen deutlich, daßB. fraudulentus apathogen fürQ. robur, F. sylvatica undP. sylvestris ist.

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Studies on the pathogenicity of the deciduous tree nematodeBursaphelenchus fraudulentus

Bursaphelenchus fraudulentus is closely related to the quarantine pestB. xylophilus and can be found in high numbers in dead or severely damaged deciduous tree species. To find out ifB. fraudulentus can be pathogenic for deciduous or coniferous trees, inoculation tests with three year old trees were conducted in the greenhouse. In addition to this, wood of infested oak trees was microscopically investigated.The microscopical evaluation of thin wood sections showed thatB. fraudulentus occurred only in the tracheae. Besides the nematodes fungal hyphae were present which could serve as food source for the nematodes. No cell or tissue destruction—which could have been attributed to a possible feeding activity of the nematodes—was visible.In a first test seriesB. fraudulentus was inoculated intoQuercus robur, Fagus sylvatica andPinus sylvestris (15,000 nematodes/tree). In a second test series combined nematodefungus-inoculations withTrichoderma sp. orVerticillium leptobactrum together withB. fraudulentus (12,000 nematodes/tree) were carried out. None of the treatments showed any chloroses or wilting symptoms during the test period (11 months) and all the trees developed new shoots in the following spring. After 11 months viableB. fraudulentus could be reisolated from the wood of all inoculated trees in varying numbers, but in general the number of nematodes represented only a small percentage of the inoculum density. The two inoculated fungiV. leptobactrum andTrichoderma sp. had no promotive effect on multiplying and spreading ofB. fraudulentus inQ. robur andF. sylvatica.These results demonstrate clearly thatB. fraudulentus is apathogenic forQ. robur, F. sylvatica andP. sylvestris.

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