Question From: J. Coffman - Galveston, Texas, United States
Q: Zinnia leaves have a white spot with a black spot in the center.
I believe your zinnias have two of the most common fungal diseases that attack zinnias. Alternaria blight and powdery mildew. Remove the plants and clean up any leaf litter in the area. This Alternaria blight spores will persist in the soil for two years so plan to plant something else in that area next summer. Best And Happy Yardening, Nancy