Gary W. Moorman, Professor of Plant Pathology
|BOTRYTIS BLIGHT||Tan spots develop on leaves. Established plants rot at the crown. Infected tissue is covered with dusty gray fungal growth.||Botrytis cinerea||Maintain low humidity by spacing plants and venting to improve air circulation. Remove dead and dying flowers and leaves. To protect healthy plants, apply a fungicide.|
|POWDERY MILDEW||White fungal growth forms on the upper surface of leaves and may form on flower petals.||Golovinomyces cichoracearum (formerly Erysiphe) or Podosphaera xanthii (formerly Sphaerotheca fuliginea). NOTE: This powdery mildew can attack cucurbits and verbena.||Apply a fungicide to protect plants.|
|PYTHIUM ROOT ROT||Roots are dark brown. Plants are wilted and yellowed.||Pythium sp.||Do not over-water plants. Pot in pasteurized media. Keep hose ends off the ground. To protect healthy plants, apply a fungicide.|
Bacterial leaf spot
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