Rich Buckley at the RU Diagnsotic Lab here in NJ gave me this advice about controlling turf diseases: 1. Avoid draught, but keep the foliage as dry as possible. 2. Mow at recommended cutting heights. 3. Aerify to reduce thatch and compaction. 4. Use resistant varieties. If anyone's interested, he teaches an outstanding class in Pest Management of Landscape Turf on 2/2/12.