Occurrence: Summer There are no distinctive leaf lesions associated with summer patch. The disease first appears as faded, wilted or reddish-brown patches of grass 2-6 inches in diameter. These patches fade to light brown rapidly as the leaves wither and die. The individual patches may expand to 12 inches in diameter.
Conditions Favoring Disease Development: Hot, humid weather. Visible symptoms usually do not become evident until temperatures reach 85°F. Lawns cut at 1 ½ inches are more severely affected than lawns cut at 2 1/4 inches. Lawns with restricted roots and/or compact soil are more severely affected than lawns with well-developed roots and/or less compact soil.
Control: Aerating to improve drainage and decrease compaction. Raise mowing height to 2 ¼ inches. Adequately water lawn to provide moisture 6 inches deep while allowing upper 1-2 inches of soil to dry out somewhat between watering cycles. Fungicide treatments help to prevent recurring of summer patch. Multiple treatments are recommended. Generally, the first treatment should be made in the spring when soil temperatures reach 65° F followed with two additional treatments at 4-week intervals (follow label instructions particularly relating to timing and rates).