Untersuchungen über Potebniamyces coniferarum in den Niederlanden

Research on Potebniamyces coniferarum in the Netherlands . A review of research done in the Netherlands on the fungus Potebniamyces coniferarum, the cause of the Phomopsis disease of Douglas fir and Japanese larch, is given.     

Untersuchungen über den Einfluß von Cuticularwachsen auf die Infektionsfähigkeit pathogener Pilze

The effect of cuticular waxes on the infection rate of pathogenic fungi. 1. Lophodermium pinastri and Botrytis cinerea . Spore germination and growth rate of germ-hyphae of Lophodermium pinastri and Botrytis cinerea are influenced by low concentrations of cuticular waxes, added to the germination medium. The stimulating effect increases with decreasing resistance of the species or race used for wax sampling. Generally the separately tested alcohol-, aldehyde-, ester-, fatty acid- and hydrocarbon fractions induce similiar but less pronounced reactions than total waxes. Exceptions occur. They led to suggestions in direction to single chemical components causing resistance. – Finally alcohol and hydrocarbon chromatOgrams of cuticular waxes for Pinus montana, P. nigra and Picea abies are presented for the first time.     

Untersuchungen über den Einfluß von Cuticularwachsen auf die Infektionsfähigkeit pathogener Pilze

The effect of cuticular waxes on the infection rate of pathogenic fungi. 2. Rhytisma acerinum, Microsphaera alphitoides and Fusarium oxysporum . Cuticular waxes of Acer and Quercus species stimulate germination rate and germ-tube development of certain foliar pathogens. The stimulation increases with host susceptibility. In the case of Rhytisma acerinum, the chemical composition of the leaf wax may be responsible for the host specificity of physiological races. Cuticular waxes showed a marked effect on Fusarium oxysporum also. In some cases, individual chemical components of different fractions seem to play a role in the mechanism of resistance.     

Untersuchungen über den Einfluß von Dimilin (Diflubenzuron) auf Wachstum und Konidienkeimung einiger insektenpathogener Pilze

Zusammenfassung Der Einfluß von Dimilin, einem Chitinsynthesehemmer, auf das Wachstum von 2 Deuteromyceten (Beauveria tenella, Metarrhizium anisopliae) und von 4Entomophthora-Arten (E. aphidis, E. culicis, E. sphaerosperma, E. thaxteriana) sowie auf die Konidienkeimung vonE. aphidis undE. thaxteriana wurde untersucht. Dabei konnte festgestellt werden, daß das Wachstum vonB. tenella und vonM. anisopliae bei praxisnahen Konzentrationen geringfügig beeinträchtigt ist, nicht jedoch jenes der geprüftenEntomophthora-Arten. Dieselben Konzentrationen stimulierten die Konidienkeimung und die Bildung von Sekundärkonidien vonE. aphidis undE. thaxteriana.

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Investigations on the influence of Dimilin (Diflubenzuron) on growth and germination of conidia of some insect pathogenic fungi

The influence of Dimilin, an inhibitor of the chitin synthesis, was tested on growth of two Deuteromycetes (Beauveria tenella, Metarrhizium anisopliae) and four species ofEntomophthora (E. aphidis, E. culicis, E. spaerosperma, E. thaxteriana) and on germination of conidia ofE. aphidis andE. thaxteriana. It was demonstrated that concentrations proposed for practical applications slightly impaired the growth ofB. tenella andM. anisopliae, but did not influence the growth ofEntomophthora species. The same concentrations stimulated germination of conidia and formation of secondary conidia ofE. aphidis andE. thaxteriana.

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Untersuchungen über die Salzverträglichkeit verschiedener Pappel-und Weidenarten sowie -klone unter Labor- und Freilandbedingungen

The salt tolerance of various poplar and willow species and clones in the laboratory and field. The resistance of 10 black and 10 grey poplar clones and of 36 willow clones was examined by dipping shoots in a higly concentrated NaCl solution. All the black and most of the grey poplars showed high resistance. Only eleven willow-clones showed sufficient resistance. The studies are to be continued with enlarged material under various ecological conditions.     

Untersuchungen iiber die Resistenzeigenschaften einiger Weißpappelklone gegenüber der Triebspitzenkrankheit

The resistance of several white poplar-clones against Pollaccia radiosa. Continuing the work of Weisgerber (1967,1968 and 1969) clone-typical forms of resistance against spring defoliation (shoot-dieback), caused by Pollaccia radiosa were investigated in several Leuce-poplarclones. The most obvious differences in attack occur under natural conditions. The observed differences concerning the type of resistance (infection versus spreading in the host) seem to depend on the anatomical structure of the host.     

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.     

Untersuchungen über Calocera viscosa Pers. ex Fr. als Wurzelfäuleerreger

Pathogenicity tests with Calocera viscosa . C. viscosa grew from wood blocks through wounds into living roots (wounded) of Pseudotsuga menziesii at growth rates comparable to Phaeolus schweinitzii and Sparassis crispa.     

Untersuchungen über den Hangabtrag im Lainbachtal bei Benediktbeuern

Ohne Zusammenfassung     

Ein Vergleich einiger forstlicher Praktiken in den Alpen und in West-Oregon

Ohne Zusammenfassung übersetzt und überarbeitet vonR. Lammel     

Untersuchungen zur biologischen Bekämpfung einiger Unkräuter und Schädlinge in Landwirtschaft und Obstbau

Ohne Zusammenfassung