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Zinnia-Fusarium Wilt See: Marigold (Tagetes spp.)- Fusarium Wilt ...

Zinnia-Powdery Mildew March 2023 See: Greenhouse Plants, Ornamental- Powdery Mildew Cause Golovinomyces spadiceus (formerly Erysiphe cichoracearum), a fungus. Overwinters as either chasmothecia or conidia on infected plants. The conidia are readily wind d ...

Zinnia-Stem Rot March 2023 Cause Sclerotinia sclerotiorum, a fungus that produces hard, black sclerotia, which can survive many years in soil. The disease develops in cool, wet conditions and is more prevalent when plants form a complete, compact canopy t ...

Zucchini Go to: Squash (Cucurbita spp.) ...

Zygopetalum-Botrytis Blight See: Greenhouse Plants, Ornamental- Gray Mold ...

Wheat (Triticum aestivum)-Stagonospora nodorum Blotch March 2023 See: Wheat (Triticum aestivum)- Septoria tritici Blotch Cause The fungus, Phaeosphaeria nodorum (anamorph Stagonospora nodorum, formerly known as Septoria nodorum), infects both leaves and g ...

Willow (Salix spp.)-Leaf Spots March 2023 See: Willow (Salix spp.)- Marssonina Leaf and Twig Spot Willow (Salix spp.)- Rust Cause Several different fungi can cause leaf spots on willow including Cylindrosporium salicinum, Drepanopeziza salicis (formerly P ...

Willow (Salix spp.)-Silver Leaf See: Cherry (Prunus spp.)- Silver Leaf ...

Willow (Salix spp.)-Wood Decay March 2023 Cause Two types of wood decay occur in living trees: white rots and brown rots. White rots appear to be more common in willow and are caused by Daedalea confragosa (soft white rot), Phellinus igniarus (white trunk ...

Yew (Taxus spp.)-Needle Blight March 2023 Cause Sphaerulina taxi, a fungus that has been reported from all states and considered common in Washington. A problem when yew is used as a hedge. Symptoms The needles of the current season are killed. Infected n ...