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Sycamore (Platanus spp.)-Leaf Scorch See: Maple (Acer spp.)- Leaf Scorch ...
Sycamore (Platanus spp.)-Powdery Mildew Cause The fungi Erysiphe platani (formerly Microsphaera platani) has been reported from Washington and Oregon. Conidia are released in response to abrupt decreases in relative humidity. Wind blows conidia to healthy ...
Spruce (Picea spp.)-Stem Decay See: Fir, Douglas and True- Stem Decays (Heart Rots) Notes: Schweinitzii root and butt rot is the most important in old-growth Sitka spruce. Most likely the problem when an old tree breaks at the butt and has a dark-brown cu ...
Strawberry (Fragaria spp.)-Charcoal Rot Cause Macrophomina phaseolina is a soilborne fungus that is favored by dry and warm soil conditions. Although the pathogen has an extensive host range, this form of the fungus is specific to strawberry. Disease deve ...
Swiss Chard (Beta vulgaris subsp. cicla)-Phoma Leaf Spot and Root Rot Cause The fungus, Pleospora bjoerlingii (syn. P. betae = Phoma betae) can cause leaf spots and root rot of table beet, sugar beet, Swiss chard, and other Beta species. The fungus is see ...
Spruce (Picea spp.)-Drought Injury See: Fir, True (Abies spp.)- Drought Injury Note: Spruce spider mites can result in a similar symptom pattern on Dwarf Alberta Spruce. Time of symptom development can help diagnose the difference between mites (gets wors ...
dwarf spruce tree
Spruce (Picea spp.)-Sparassis Root Rot Cause Sparassis crispa (formerly Sparassis radicata), a fungus reported to be common in Washington on Engelmann spruce. Can also occur on Douglas-fir, ponderosa pine, white fir, and southwestern white pine. Both hear ...
Stock (Matthiola spp.)-Downy Mildew See: Alyssum- Downy Mildew Cause Hyaloperonospora parasitica (formerly Peronospora parasitica), a fungus-like organism. Different strains infect different host such that downy mildew from stock will only infect stock. M ...
Sword Fern (Polystichum munitum)-Die-off Cause Unknown. Large areas of uniform patches of sword fern understory have been observed to die-off in the Puget Sound area of Washington including Seward Park in Seattle (in 2013), Kitsap Peninsula (in 2010), and ...
Sedum-Powdery Mildew See: Greenhouse Plants, Ornamental- Powdery Mildew Cause Powdery mildew has been found several times by the OSU Plant Clinic. Three powdery mildew species, Erysiphe sedi, Erysiphe umbilici and Golovinomyces orontii (formerly Erysiphe ...