decay", or "seedling blight" of turfgrasses. This is most common in Perennial ryegrass (Lolium perenne) and happens in areas that are high above the recommended seeding rates. Not only does Pythium devastate the Turf canopy but the oomycete can also attack the roots and crowns, which will reduce growth, become off-colored, and cause thinning of turf. Cultural control Kentucky bluegrass and Fescue are less susceptible to Pythium blight than Perennial ryegrass and Bentgrass. Creating an environment that includes adequate drainage, good air movement, and balanced fertility will help prevent the disease. Removing dew during hot and humid weather will also help prevent Pythium. Dew can be removed from the grass from mowing, using a backpack blower, or dragging a hose across the grass. Install an internal drainage system if you have severe drainage problems. Improve air circulation (Installing fans, removing trees or shrubs) and avoid irrigation practices that will leave moisture on the grass blades for extended periods of time. An adequate aeration program will relieve compaction and improve drainage. Aeration should annually disrupt between 15-20% of the total surface area. Be sure that you are not applying excess nitrogen to your soil. Avoid using quick release fertilizers, try using slow release ammonium sources. If your soil pH is above 6.5 then use ammonium sulfate, which will acidify your soil. Most balanced fertility programs for Kentucky Bluegrass lawns will consist of applying of nitrogen per a year. Chemical control If severe enough or on high valued turf (ex. golf greens) Pythium can be controlled with the use of fungicides. To stop the spread of Pythium in bentgrass and perennial ryegrass will most often have to involve a fungicide. Timing is critical to prevent or stop the spread of Pythium, if continued hot, wet weather is expected, apply fungicides at the first sign of symptoms. Preventative fungicide applications may be applied if necessary. Fungicides should be applied according to the instructions on the label. Minimize the cost of applying fungicides by selecting fungicides that will work on a wide range of turfgrass diseases at the same time. References Turfgrass diseases Pythium