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Grape Disease - Powdery Mildew

Developed by Mark Bell, Frank Zalom, Emily Symmes, and Mark Henderson (July 2009) "What is Grape Powdery Mildew? Grape powdery mildew (Erisiphe necator) is a fungal disease found on grape leaves and young berries. Symptoms of the disease include red blotches on the canes during dormancy and fuzzy white spots on the topsides of leaves. Approximately one week after initial infection, the fungus produces its signature whitish “powder” areas that are actually masses of spores that can colonize the entire berry surface. What is the Damage Caused? Powdery mildew (PM) can cause severe damage to leaves and grape berries, lowering yield and quality of the harvest. The disease may create off odors in grape berries. "

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