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Sugar Beet (Beta vulgaris)-Rhizoctonia Root and Crown Rot March 2023 By O. Neher and C. M. Ocamb Cause Rhizoctonia solani is a fungus that survives primarily as mycelium or sclerotia in plant debris. Rhizoctonia solani becomes active when soil is 77°F to ...

Sugar Beet (Beta vulgaris)-Rhizomania March 2023 By O. Nehers and C. M. Ocamb Cause A virus (Beet necrotic yellow vein virus) transmitted by a fungus (Polymyxa betae) commonly found in soil. The disease was first detected in Idaho, Wyoming, and Nebraska i ...

Sunflower (Helianthus spp.)-Powdery Mildew March 2023 Cause The fungi, Golovinomyces cichoracearum (formerly Erysiphe cichoracearum), has been reported from Idaho and Washington and G. spadiceus has been reported from Washington. Podosphaera xanthii and G ...

Sunflower (Helianthus spp.)-Sclerotinia Wilt and Head Rot March 2023 Cause The fungus Sclerotinia sclerotiorum overwinters as black sclerotia in soil, among seeds, and in plant debris for 3 to 7 years. Dry, cool soil conditions favor survival of sclerotia ...

Sunflower (Helianthus spp.)-Sunburn March 2023 Cause Heat or moisture stress can result in a sunburn on the flower heads. Symptoms Brown or blackened areas on the side of the plant continuously exposed to sun. Cultural control Maintain adequate irrigation ...

Sunflower (Helianthus spp.)-Verticillium Wilt March 2023 Cause Verticillium dahliae, a fungus that survives in soil as microsclerotia. Another species V. isaacii has also been isolated from wilted sunflower plants in the Columbia Basin, Washington. Surviv ...

Sweetpea (Lathyrus odoratus)-Fasciation See: Greenhouse Plants, Ornamental- Shoot Proliferation and Leafy Gall ...

Sweetpea (Lathyrus odoratus)-Mosaic See: Pea (Pisum sativum)- Pea Enation Mosaic ...

Sweetpea (Lathyrus odoratus)-Powdery Mildew March 2023 Cause Erysiphe pisi var. pisi (formerly Erysiphe polygoni), has been reported from the Pacific Northwest; Erysiphe lathyricola (formerly Microsphaera diffusa) has been reported from Oregon. Erysiphe t ...

Sweetpea (Lathyrus odoratus)-Root Rot See: Pea (Pisum sativum)- Root Rots ...