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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 File Format application/pdf Remove constraint File Format: application/pdf

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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
    Full Text:
    . ...........................................................85 4.2. Size of stem lesions on pear trees sprayed with disease control products and

  • 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...
    Resource Type:
    Dissertation
    Full Text:
    , 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)...
    Resource Type:
    Dissertation
    Full Text:
    ............................................................................................... 103 SEASONAL OVIPOSITION BY DELIA RADICUML. IN RUTABAGA AND TURNIP CROPS IN OREGON

  • 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
    Full Text:
    Basin of Oregon. Plant Disease 87:1449-1456. Harvey, J.J., J.C-Y Han, and R.W. Reiser. 1978a

  • Responses and relationships among Fusarium species, sweet corn, and western spotted cucumber beetles

    Creator:
    Miller, Nathan L. (Nathan Louis)
    Abstract:
    Sweet corn (Zea mays L.) yields in the Willamette Valley of Oregon have been declining since the early 1990’s. Studies were done to determine if there is a relationship between ear weight and several disease parameters including necrotic crowns or stalk nodes, nodal root rot, radicle root rot, and sub-crown...
    Resource Type:
    Dissertation
    Full Text:
    . Studies were done to determine if there is a relationship between ear weight and several disease