Plant Disease Management Handbook

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In the center are dark old telia while new telia are forming to either side. They start out white and progressively turn dark red from the bottom up.

Jay W, Pscheidt, 2008.

Leaves are OK but stems are overly thickened.

Photo by Jay W. Pscheidt, 1993.

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Tanoak (Notholithocarpus densiflorus) - Sudden Oak Death

Rhododendron - Ramorum Leaf Blight and Shoot Dieback

Image related to Huckleberry (Vaccinium spp.)-Ramorum Leaf Blight and Shoot Dieback

This sprout is brown and necrotic with tip dieback from this disease.

Photo by Everett Hansen

Note stems and leaves with dieback symptoms.

Photo by Djibo Zanzot

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Blueberry (Vaccinium corymbosum) - Mummy Berry

Image related to Huckleberry (Vaccinium spp.)-Mummy Berry

Note the spots on the leaves.

OSU Extension Plant Pathology Slide Set.

Red arrow points to mummified fruit of black huckleberry, Vaccinium membranaceum. Mount Revelstoke and Glacier National Parks, British Columbia.

Mindy Skinner, 2014.

Mummy berry found on Vaccinium membranaceum in the Wallowa mountain area.

Christina Hagerty, 2018.

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Azalea (Rhododendron spp.) - Leaf and Flower Gall

Puckered areas on leaves due to Exobasidium sp.

OSU Extension Plant Pathology Slide Collection, 1960.

Note the puckered areas on the leaves.

OSU Extension Plant Pathology Slide Collection, 1960.

Exobasidium vaccinii on evergreen huckleberry, note the reddish-orange coloration of infected leaves.

Jay W. Pscheidt, 1991.

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Greenhouse Plants, Ornamental - Gray Mold

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Greenhouse Plants, Ornamental - Impatiens Necrotic Spot

Hosta Virus X with symptoms of leaf puckering and mosaic.

Photo by Melodie Putnam, 2005

Hosta Virus X mosaic symptoms.

Melodie Putnam, 2006.

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Greenhouse Plants, Ornamental - Shoot Proliferation and Leafy Gall

Image related to Hosta-Shoot Proliferation and Leafy Gall

Pieces of shoot proliferation have been removed from a hosta plant infected by R. fascians.

Melodie Putnam, 2008.

Rhodococcus fascians causes proliferation of buds, which may expand into stunted shoots, as shown on the right.

Melodie Putnam, 2008.

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Cabbage and Cauliflower (Brassica oleracea) - Oedema (Edema)

Cause Spots on hosta leaves may appear to be caused by disease but are a result of environmental conditions.

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Greenhouse Plants, Ornamental - Gray Mold

Leaf spots due to Botrytis were at first water-soaked then turned necrotic.

OSU Plant Clinic Image, 2013.

Botrytis was isolated from these leaf blights.

OSU Plant Clinic Image, 2013.

Cause Albugo candida, a fungus-like microorganism, can cause disease on all crucifers including horseradish, arugula, rapeseed (canola), radish, leafy brassicas, head and stem brassicas, and wild mustards. The fungus overwinters as oospores in plant debris or as mycelium in perennial plants. The oospores can germinate and infect young plants, leading to pustules on the plant. Sporangia are produced in pustules, can be moved by wind, rain, or insects, and can germinate, giving rise to zoospores.