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Filtering by: Creator United States Remove constraint Creator: United States Academic Affiliation Botany and Plant Pathology Remove constraint Academic Affiliation: Botany and Plant Pathology Degree Name Doctor of Philosophy (Ph.D.) Remove constraint Degree Name: Doctor of Philosophy (Ph.D.)

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  • Biology and management of Meloidogyne chitwoodi using oxamyl on potato in the western United States

    Creator:
    David, Nicholas L.
    Abstract:
    Field trials were conducted during 2001 to 2003 to investigate soil population dynamics of Meloidogyne chitwoodi, tuber symptom suppression using oxamyl, and post-harvest tuber symptom development on short-season potato varieties Russet Norkotah and Russet Nugget (San Luis Valley only). The experiments were located in the San Luis Valley in Colorado,...
    Resource Type:
    Dissertation
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    the Western United States. Abstract approved: Russell E. Ingham Field trials were

  • Ecological thresholds, climate extremes, and tree species' distributions across the Pacific coastal United States

    Creator:
    Lintz, Heather E.
    Abstract:
    Species' distributions across the landscape are perhaps the least understood yet most conspicuous features of life on earth. Ecologists have long studied species' distributions; yet, many questions remain about why species occur where they do. Such questions persist largely because species' distributions are complex systems with challenging properties like non-linearity,...
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    Dissertation
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    Extremes, and Tree Species’ Distributions across the Pacific Coastal United States. Abstract

  • Fescue taxonomy in the Pacific coast states

    Creator:
    Wilson, Barbara L.
    Abstract:
    Accurate taxonomy is essential to preservation and management of native grasses. Four problems in fescue taxonomy were investigated: the identity of the native fescue that dominates western Oregon and Washington prairies, the relationship of native Festuca roemeri to closely related grasses, the status of F. howellii and F. washingtonica, and...
    Resource Type:
    Dissertation
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    the Pacific Coast States by Barbara L. Wilson A THESIS submitted to Oregon State University in

  • A revision of Juncus subgenus genuini (Juncaceae) in the Pacific states

    Creator:
    Lint, Harold LeRoy
    Abstract:
    A study was made of the subgenus Genuini of the genus Juncus in the Pacific States, California, Oregon and Washington. Extensive morphological comparisons, geographical distributions, habitat differences and observations of apparent presence or absence of natural hybrids provided the major data sources. Cytological studies were made, but were inconclusive. Eleven...
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    Dissertation
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    States by Harold LeRoy Lint A THESIS submitted to Oregon State University in partial fulfillment of

  • Responses of forest understory plants to burial by volcanic tephra from Mount St. Helens, Washington

    Creator:
    Antos, Joseph A.
    Abstract:
    The effects of burial by tephra (volcanic aerial ejecta) on forest understory plants were examined northeast of Mount St. Helens, Washington, in the area where the 18 May 1980 eruption deposited tephra but did not destroy canopy trees. At six sites along a tephra depth gradient from 2-15 cm, understory...
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    Dissertation
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    Joseph A. Antos A THESIS submitted to Oregon State University in partial fulfillment of the

  • 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...
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    Dissertation
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    disease in the western United States was described. Then, the ecological role of the most abundant

  • Taxonomy of Phacelia section Miltitzia (hydrophyllaceae)

    Creator:
    Halse, Richard R.
    Abstract:
    A systematic study was made of the species comprising Phacelia section Miltitzia. These species, which are commonly found in the Great Basin physiographic province of western North America, are distinguished from other members of Phacelia by their yellow, marcescent corollas and their transversely corrugated seeds. This project utilized morphological, cytological,...
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    Dissertation
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    from 20 he in the United States. An artificial key to the nine species and two varieties of section

  • An analysis of montane forest vegetation on the east flank of the central Oregon Cascades

    Creator:
    West, Neil E.
    Abstract:
    Montane forest vegetation as it occurs on the east flank of the central Oregon Cascades has provided excellent conditions for a "natural experiment" in the use of various methodologies in studying vegetational distribution. This "experiment" has reflected on some theory and practice for the discipline of plant synecology. Detailed descriptions,...
    Resource Type:
    Dissertation
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    developed and been practiced principally in the north -central United States. These ±-1:,.R so

  • Identification and Occurrence of Sweet Cherry (Prunus avium) Virus and Virus-Like Diseases in Various Regions and Orchards of Oregon

    Creator:
    Reinhold, Lauri A.
    Abstract:
    There are over 35 known virus and virus-like diseases of sweet cherry (Prunus avium), some with potential to cause severe economic impact by reducing vegetative growth, vigor, and/or quality of fruit. Oregon is the second-ranked state for sweet cherry production in the United States with 13,000 acres and $70.8 million...
    Resource Type:
    Dissertation
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    United States with 13,000 acres and $70.8 million in production value. Statewide surveys were conducted

  • Development of the storage organ of Brassica campestris L.

    Creator:
    Larson, Ann Marie
    Abstract:
    Developmental changes in the storage organ of Brassica campestris L. were followed from the organization of the embryonic radicle and hypocotyl to the mature storage organ. Three independent primary meristems gave rise to the cortex, the stele, and the root cap-epidermis. The primary development is typical of the Cruciferae. Cambial...
    Resource Type:
    Dissertation
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    which in the upper hypocotyl united to form a continuous band between the xylem and the pith. In the