I just installed 2K sq.ft. of Tall Fescue and noticed Pythium blight. If I understand correctly Pythium blight is a white web fungus in lawns. Should I treat it or should I replace it? The weather is warm during the day and cold in the evening. Pythium blight is only noticed in the shady areas and I am only watering it once a week. Please help. Any info. is greatly appreciated.