Rake out the dead grass and reseed if necessary. Brown Patch Brown patch is not so common as some other diseases. The fungus that causes the disease can be found in most soils and can live for years without a host plant. Symptoms are brown patches of grass ranging from a few inches to several feet in diameter. Infected leaves are at first water-soaked but later dry and turn dark brown.
Brown patch has a slimy appearance when it infects perennial ryegrass.
Avoid high nitrogen levels during hot, humid seasons and remove the dew in early morning to reduce the disease severity. Fungicides labeled for brown patch control and readily available to homeowners include Daconil 2787, Dyrene and Fore. The dollar spot fungus is most active when the temperature is between 70 and 90 degrees. The disease is spread by infected clippings moved about by mowers, hoses and shoes. The symptoms are sunken, straw-colored spots about the size of a quarter to a silver dollar.