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Filtering by: Subject Pear -- Diseases and pests -- Oregon Remove constraint Subject: Pear -- Diseases and pests -- Oregon Degree Level Doctoral Remove constraint Degree Level: Doctoral Rights Statement In Copyright Remove constraint Rights Statement: In Copyright

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  • Factors affecting the incidence and severity of Phytophthora syringae cankers in pear (Pyrus communis) trees

    Creator:
    Laywisadkul, Srisangwan
    Abstract:
    Container grown pear trees were used to determine the effects of the following factors on the susceptibility to Phytophthora syringae: 1) tree nitrogen (N) status and foliar sprays of urea and copper-EDTA (CuEDTA); 2) dormancy and environmental conditions; 3) wound and wound age; and 4) chemical and biological control measures....
    Resource Type:
    Dissertation
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    . ...........................................................85 4.2. Size of stem lesions on pear trees sprayed with disease control products and

  • Studies on the etiology and epidemiology of bull's eye rot of pears

    Creator:
    Henriquez, Jose Luis, 1961-
    Abstract:
    The objective of this dissertation is to introduce low-cost processing methods for the fabrication of ZnO transparent thin-film transistors (TTFTs). A novel method for depositing ZnO body layers via spin-coating of a zinc nitrate-based spin solution is presented. The processing conditions of spin-coated ZnO are optimized to produce continuous and...
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    Dissertation
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    Columbia, Oregon and Washington. The disease is also important in Europe; in Germany bull's eye rot is

  • Plant hormone-induced defense responses against Botrytis cinerea

    Creator:
    Akagi, Aya
    Abstract:
    Several plant hormones, including ethylene and jasmonates, are known to mediate responses against biotic and abiotic stress. The first and second objectives of this thesis were (i) to elucidate the role of ethylene in defense responses against Botrytis cinerea and specifically (ii) to determine the potential contribution of ethylene response...
    Resource Type:
    Dissertation
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    biosynthesis was found to stimulate infections of pear and apple fruits by B. cinerea, respectively. This

  • Phytophthora species and riparian alder tree damage in western Oregon

    Creator:
    Sims, Laura L.
    Abstract:
    The genus Phytophthora contains some of the most destructive pathogens of forest trees, including the most destructive pathogen of alder in recent times, Phytophthora alni. Alder trees were reported to be suffering from canopy dieback in riparian ecosystems in western Oregon, which prompted a survey of alder health and monitoring...
    Resource Type:
    Dissertation
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    another Phytophthora species could be causing disease in western Oregon, and that this disease would go

  • Biology of sweet cherry powdery mildew

    Creator:
    Calabro, Jill M.
    Abstract:
    The Pacific Northwest has become one of the nation’s premier sweet cherry, Prunus avium, production areas. As production of sweet cherries has flourished in Oregon and Washington, so has powdery mildew, caused by the fungus Podosphaera clandestina, which infects both foliage and fruit causing severe economic damage to growers. Sweet...
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    Dissertation
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    , Prunus avium, production areas. As production of sweet cherries has flourished in Oregon and

  • Phenology and monitoring of the cabbage maggot, Delia radicum (L.), in brassica root crops

    Creator:
    Dreves, Amy J.
    Abstract:
    In Oregon’s northern Willamette Valley, cabbage maggot (CM), Delia radicum (L.) (Diptera: Anthomyiidae) often renders Brassica root crops unmarketable. Scheduled insecticides are the only current control. Studies were conducted to: 1) describe and characterize spring emergence of CM flies and their seasonal flight activity relative to degree-day (DD) accumulations; 2)...
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    Dissertation
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    ............................................................................................... 103 SEASONAL OVIPOSITION BY DELIA RADICUML. IN RUTABAGA AND TURNIP CROPS IN OREGON

  • Marking, movement, and management of Drosophila suzukii in Oregon berry crops

    Creator:
    Klick, Jimmy
    Abstract:
    Drosophila suzukii Matsumura (Diptera: Drosophilidae) are small invasive flies that in the past five years (2009-2014) invaded berry and stone fruit production regions in Europe and the Americas. Evolutionary adaptations, biological traits, and anthropogenic factors have contributed to its current status as a global pest. Females oviposit eggs into ripe...
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    Dissertation
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    , Movement, and Management of Drosophila suzukii in Oregon Berry Crops Abstract approved

  • The epidemiology of sudden oak death in Oregon forests

    Creator:
    Peterson, Ebba K.
    Abstract:
    The phytopathogen Phytophthora ramorum (Werres, DeCock & Man in't Veld), causal agent of Sudden Oak Death (SOD) of oaks (Quercus spp.) and tanoaks (Notholithocarpus densiflorus syn. Lithocarpus densiflorus), is established in coastal forests of the western United States. Since the discovery of SOD in the Douglas-fir / tanoak forests of...
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    Dissertation
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    and infection occur more often in Oregon than in California. These data can explain the failure to

  • Characterization, epidemiology, and ecology of a virus associated with black raspberry decline

    Creator:
    Halgren, Anne B.
    Abstract:
    The objective of this study was to characterize an unknown agent associated with decline in black raspberry (Rubus occidentalis) in Oregon. A virus was found consistently associated with decline symptoms of black raspberries and was named Black raspberry decline associated virus (BRDaV). Double stranded RNA extraction from BRDaV-infected black raspberry...
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    Dissertation
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    , feedback, and genuine interest in my project. The Oregon black raspberry growers made this research

  • ALS-inhibitor resistant downy brome (Bromus tectorum L.) biotypes in Oregon : Mechanism of resistance, fitness, and competition

    Creator:
    Park, Kee-Woong
    Abstract:
    Understanding the mechanism of resistance, relative fitness and competitiveness of herbicide resistant biotypes is important to predict population dynamics and to establish resistance management strategies. This study was conducted to determine the level of resistance to acetolactate synthase (ALS) inhibitors and the mechanism of resistance of ALS-inhibitor resistant downy brome...
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    Dissertation
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    Downy Brome (Bromus tectorum L.) Biotypes in Oregon: Mechanism of Resistance, Fitness, and Competition