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Filtering by: Creator Johnson, T. M. Remove constraint Creator: Johnson, T. M. Academic Affiliation Botany and Plant Pathology Remove constraint Academic Affiliation: Botany and Plant Pathology Degree Level Master's Remove constraint Degree Level: Master's

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  • Effect of resident epiphytic fungi development of brown rot blossom blight of stone fruits

    Creator:
    Wittig, Hans P. P.
    Abstract:
    Antagonistic effects of Epicoccum purpurascens, Aureobasidium pullulans, Trichoderma spp., and Botrytis cinerea on establishment of Monilinia fructicola infections in cherry and peach blossoms were assessed in field and mist chamber studies. Conidia of each fungus were applied to blossoms that were subsequently inoculated with conidia of M fructicola. Mist chamber...
    Resource Type:
    Masters Thesis
    Full Text:
    . Johnson Abstract approved: Antagonistic effects of Epicoccum purpurascens, Aureobasidium pullulans

  • Systematics of the genus Torrubiella

    Creator:
    Johnson, Desiree M.
    Abstract:
    Torrubiella is a genus of entomopathogenic fungi in the Clavicipitaceae (Ascomycota). Species of the genus produce superficial perithecia on a loose mat of hyphae that forms directly on the host. The genus is estimated to contain about 70 species. Torrubiella is hypothesized to be a close relative of Cordyceps because...
    Resource Type:
    Masters Thesis
    Full Text:
    M. Johnson for the degree of Master of Science in Botany and Plant Pathology presented on March 20

  • Evaluation of kasugamycin-use strategies designed to delay development of resistance in Erwinia amylovora

    Creator:
    Hubbard, Andrew Robert
    Abstract:
    The antibiotics, streptomycin sulfate and oxytetracycline, are used widely for fire blight suppression in the Pacific Northwest region of the United States. The efficacy of streptomycin, however, is compromised by widespread streptomycin-resistance in E. amylovora populations, and oxytetracycline is only partially effective. Consequently, for several years, the aminoglycoside antibiotic, kasugamycin...
    Resource Type:
    Masters Thesis
    Full Text:
    approved: ______________________________________________________ Kenneth B. Johnson The

  • Epiphytic yeasts isolated from apple leaves to control of gray and blue mold fruit rots of apple

    Creator:
    Falconi, Cesar E.
    Abstract:
    Eight phylloplane yeasts were isolated from backyard apple trees in Corvallis, OR. Yeast isolates were classified to genus or species level. All isolates were tested in vitro for antagonistic activity against the postharvest pathogens Botrytis cinerea and Penicillium expansum. Of these isolates, Aureobasidium pullulans, Sporobolomyces roseus Rhodotorula sp., consistently reduced...
    Resource Type:
    Masters Thesis
    Full Text:
    . Johnson, major professor, for his guidance and advice throughout this research. I would like to thank

  • Assessment of potato tuber blight caused by Phytophthora infestans

    Creator:
    Glass, Jenny Rebecca
    Abstract:
    Late blight, caused by Phytophthora infestans, is a devastating problem to potato production in many parts of the world. While the foliar phases of this disease are well characterized, tuber infection, leading to quality losses and disease perpetuation, is less well understood. Experiments were conducted during 1998 and 1999 in...
    Resource Type:
    Masters Thesis
    Full Text:
    Redacted for privacy Redacted for privacy ACKNOWLEDGMENTS I thank Kenneth B. Johnson, Teresa Sawyer

  • Modification of phyllosphere environments to enhance establishment of Gliocladium roseum, an antagonist of Botrytis cinerea

    Creator:
    Bennett, Robert J. (Robert Joe), 1953-
    Abstract:
    Radial colony growth of three isolates of Gliocladium roseum and three isolates of Bottytis cinerea were measured on 1/4 strength potato dextrose agar amended with concentrations of NaHCO₃ ranging from 0-2% (w/v). Compared to the control, reductions in colony diameter of the B. cinerea isolates ranged from 60-79% and 73-89%...
    Resource Type:
    Masters Thesis
    Full Text:
    Bottytis cin ea. Abstract approved : . Johnson Radial colony growth of three isolates of Gliocladium

  • Role of inoculum sources of Botrytis cinerea in the epidemiology of gray mold of snap beans

    Creator:
    Johnson, Kenneth Bjorn
    Abstract:
    Spore dispersal gradients and pod disease gradients from point inoculum sources of Botrytis cinerea were measured over time in two snap bean field experiments. Laboratory grown inoculum was placed at ground level in a 30 x 30 cm square at bloom initiation and removed at full bloom. Dispersal of inoculum,...
    Resource Type:
    Masters Thesis
    Full Text:
    Cynthia Flack for Kenneth Bjorn Johnson ACKNOWLEDGEMENTS I wish to express my gratitude to Dr. M. L

  • Pathogenicity of Phytophthora species from Oregon waterways

    Creator:
    Navarro, Sarah M.
    Abstract:
    Described as one of the most destructive pathogens of agricultural crops and forest trees, Phytophthora is a genus of microorganisms containing over 100 known species. Phytophthora alni has caused collar and root disease in alders throughout Europe and a form of the species has recently been isolated in North America....
    Resource Type:
    Masters Thesis
    Full Text:
    AN ABSTRACT OF THE THESIS OF Sarah M. Navarro

  • Development and control of benomyl-tolerant Botrytis cinerea strains on snap beans (Phaseolus vulgaris)

    Creator:
    Johnson, Earl Ray
    Abstract:
    Benomyl-tolerant Botrytis cinerea was found in snap bean fields throughout the Willamette Valley while no tolerant isolates of Whetzelinia sclerotiorum were detected. Thirty-five benomyl-tolerant isolates of B. cinerea had slower radial growth rates than eighteen benomyl-sensitive isolates. Sporulation of an aggressive tolerant isolate was not stimulated when grown on benomyl-treated...
    Resource Type:
    Masters Thesis
    Full Text:
    Stayton, Oregon (Johnson, M. S. Thesis). Thus, it is unlikely that the increase of benomyl-tolerant

  • Enhancement of biological control for postharvest diseases of pear

    Creator:
    Benbow, Jesse M.
    Abstract:
    Yeast biocontrol agents that were applied to 'Bose' and 'Anjou' pears in the field up to three weeks prior to harvest were found to survive on the fruit at high population levels on both pear varieties. Cryptococcus infirmo-miniatus, Cryptococcus laurentii, and Rhodotorula glutinis maintained populations averaging 5 x 10⁶ cfu/fruit...
    Resource Type:
    Masters Thesis
    Full Text:
    pear AN ABSTRACT OF THE THESIS OF Jesse M. Benbow for the degree of Master of Science in Botany and