On the coast we have a constant battle with fungi. Most grasses will tolerate a pH of 6.5 quite well. Since a fungus does not like a pH that low I tried to maintain with sulfur to keep it as low as possible. Wettable sulfur is actually sold as a fungicide by Bonide. A good idea as Runner explained many years ago is to feed the roots in the fall to store sugars for the upcoming year. Lowering the Nitrogen is "Iffy" with me as I've not seen too many reports verifying that it leads to fungus problems. Of course a timely rotations of fungicides to combat the problems are still the best defense. Brown Patch does not like heat and mostly disappears on the coast with high temps but shows up again when the nights get cooler. Another helpful thing is to pick up the grass clippings after mowing to keep the air moving to the grass stems. Of course watering during the morning hours so the lawns dry off during the day is foremost. It's constant battle and you just cannot drop your guard and charge accordingly.
We all are merely gleaners from the masters who were here before us.