Leaf spots are circular to elongate, straw-colored, and surrounded by reddish-brown borders. During long periods of wet weather, many of the spots may be surrounded by a margin of water-soaked tissue.
Severe infection often causes the leaves to wither. A diseased stand of bent grass may give a drought- injured appearance, even though soil moisture is adequate.
Red Leaf Spot is a warm, wet weather disease, usually first seen in late May or early June and reaching it speak in late July and August. The leaf blighting and "droughtstricken" phase of the disease usually occurs during this period, particularly after longs periods of wet weather.
On bent grass, the disease is first seen as smoky-blue, irregularly shaped turf areas, varying from 1 to 4 feet in diameter. Soon after, the grass plants yellow and die. Finally, these areas appear water-soaked and matted down. This disease may appear in the spring on home lawns as well as on bent grass greens and fairways.
On the leaves, the first symptoms are minute yellow flecks, which soon progress to irregularly shaped, water-soaked blotches.