Because of this root problem, we may start to see signs of wet wilt this summer. Wet wilt occurs during hot and humid periods when soils are waterlogged, or when the roots cannot absorb water quick enough to meet transpiration needs of the plant.
Affected grass initially appears brownish and water-soaked. Turf soon thins out in irregular shapes. Eventually, leaves and sheaths collapse and turn white. A week or two later, dead areas develop a blackish appearance. This condition is difficult to diagnose and can be confused with summer lawn diseases.
For more information, visit: http://www.usga.org/turf/green_section_record/2006/mar_apr/understanding.html