I have a friend who has a lawn treatment company fertilize her lawn each year. This year for about 3/4 of the summer her grass looks like it was cut with a very dull lawn blade. The lawn mower is ok and the blade is very sharp. The grass tips (about 1/2 to 3/4 inch down) are brown. I believe this is a form of fungus. The lawn company says the same thing but doesn't think there is anything they can do for it. Is the lawn getting too much fertilizer? What can be done to eliminate this problem?
It really takes more than simple description to diagnose lawn problems, but I think there's a good chance that this could be fertilizer burn. Fungus generally affect roots, and that would not be likely to show on the ends of the grass blades. I would take some samples of the grass, with roots and soil also, to the county extension service where they can give you their assessment of the situation. This link will help you locate the nearest one: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm