Brown patch

The symptoms of brown patch can vary depending on the grass cultivar, climactic and atmospheric conditions, soil and intensity of the turfgrass management. This disease typically causes rings or patches of blighted turfgrass that measure 5 inches to more than 10 feet in diameter.

It also causes leaf spots and "smoke rings"—thin, brown borders around the diseased patches that appear most frequently in the early morning. After the leaves die in the blighted area, new leaves can emerge from the surviving crowns. On wide bladed species, leaf lesions develop with tan centers and dark brown to black margins.

Conditions for Development Brown patch favors high relative humidity as well as temperatures of over 85°F during the day and over 60°F at night. This disease can be quite active at cool temperatures on warm season grasses in the spring and fall. It also occurs in areas that experience more than 10 hours a day of foliar wetness for several consecutive days. Brown patch infestation is more severe when the turf is cut to a height less than the optimum for the turfgrass being grown. Control Measures Use low to moderate amounts of nitrogen, moderate amounts of phosphorous and moderate to high amount of potash. Avoid nitrogen applications when the disease is active. Increase the height of cut. Increase the air circulation. Minimize the amount of shade. Irrigate turf early in the day. Improve the drainage of the turf. Reduce thatch. Remove dew from turf early in the day.