Pythium root rot occurs at any point in the growing season when the soil remains saturated for prolonged periods of time, such as several days or weeks. This can be a result of poor surface or subsurface drainage, over-irrigation, heavy rainfalls, and excessive thatch and organic matter accumulation. The turfgrass can appear orange or yellow from a distance, often in irregular patterns or occasionally as distinct patches. Often the symptoms spread along drainage patterns. On individual plants, the crowns, roots, rhizomes and/or stolons will appear dark and greasy. The depth and density of the roots will be drastically reduced in affected areas.