Brown Patch is a fungal disease that can quickly cause a lot of damage to your lawn. It develops when day and night temperatures and humidity are high. To reduce the chances of developing Brown Patch in your lawn, learn the factors that contribute to brown patch disease developing in the first place, as proper management can reduce the chances of developing it.

• Avoid fast-acting, high-nitrogen fertilizers after March 15 and before September 15. Brown patch loves over-fertilized, soft growth as it is easier to infect.
• Don't mow too short, or let grow too long. Shorter blades of grass produce less food energy for the grass plant, weakening it and making it less able to fight off infection. Don't cut fescue shorter than 3" and bermudagrass 2 1/2". Let grow too long and humidity at grass level increases, increasing the risk of infection.
• More on mowing: mow frequently enough that you remove no more than 1/3 of the blade length at one time. Removing more stresses the grass and stressed grass is more susceptible to infection.
• Avoid watering at night. Reducing humidity around the grass blades by letting water evaporate during the day and keeping grass as dry as possible at night helps. (there's not much you can do about dew or evening rain, but why make it worse?)
• Aerate regularly, preferably in both spring and fall. The added air circulation will help keep humidity lower at grass level.