Fig. 18. As previously found in the midwestern United States, O. herpotricha is more virulent than O. korrae in North Carolina as well. Nineteen months after inoculation, 98% of O. herpotricha inoculations induced spring dead spot symptoms, and patches averaged 22 cm in diameter (three patches on right), whereas 60% of O. korrae inoculations induced spring dead spot symptoms, and patches averaged 9.4 cm in diameter (three patches on left).

Image from Plant Health Progress article:
Spring Dead Spot of Bermudagrass: A Challenge for Researchers and Turfgrass Managers