Which disease is characterized by a frog eye pattern on dead turf?

• A. Powdery mildew
• B. Fairy rings
• C. Dollar spot
• D. Necrotic ring spot

Answer: (D)

That frog-eye pattern is a hallmark of necrotic ring spot. This disease creates patches of dead turf that often show a green, healthy center, giving a ring-and-eye appearance similar to a frog’s eye. It’s caused by a fungal pathogen (Ophiosphaerella korrae and related species) that infects the turf and forms those circular necrotic patches.

Powdery mildew would show as a white powdery coating on leaf blades, not rings. Fairy rings produce a green ring around a dead patch and may have mushrooms at the edge, rather than a distinct green center within dead tissue. Dollar spot forms small, straw-colored lesions with a yellow halo, not the circular dead patch with a green eye in the middle.

So the frog-eye pattern on dead turf points to necrotic ring spot.