Summer Patch (Magnaporthe poae), Summer patch occurs between the hottest periods of June through September. The disease begins as scattered small round patches of thin, wilted or slow-growing turf. Initially, affected patches may be only 3 to 8 cm in diameter, but they may enlarge to about 30 cm in diameter and range from grayish green to light tan or straw-colored. As patches enlarge, they may coalesce and form crescents of yellow or tan turf. Summer patch blighted areas often occur on lawn sites that receive direct sun and are on south-facing slopes or near sidewalks, driveways, buildings, or otherwise stressed areas. In the cool weather of autumn, the grass may begin to grow into these dead areas again. The disease, however, is likely to reappear in previously affected areas the following summer, and to increase in intensity. Summer patch is less of a problem during cool summers with adequate rainfall.