Every lawn eventually falls victim to turf disease, from the well-manicured expanse of the golf course to the sometimes neglected backyard. This problem is devastating for the landowner following a significant investment in establishing and maintaining their lawn. However, the destruction of turf infection is not irreparable. General Cause and Prevention Lawn diseases, like human diseases, infect susceptible hosts. Likewise, identifying lawn diseases is sometimes difficult because they do not always have distinct characteristics that tend to manifest with the same symptoms. Grasses vary in their resistance to disease; however, when environmental conditions are favorable for specific pathogens, infection occurs. Proper watering, mowing, aeration, sunlight and fertilization help prevent or control problems by providing a disease-resistant environment. High Moisture Grass Diseases Brown Patch: This turf disease typically infects most grasses, initially appearing as a small patch of damp, dark grass. before progressing towards circular or horseshoe-shaped patches of brown grass surrounded by a yellowish ring. The spots expand rapidly, progressing in size to several feet in width. According to American-Lawns.com, this disease thrives in daytime temperatures of 75 to 85 degrees and nighttime temperatures above 65 degrees. Brown patch disease responds well to consistent fertilization, early morning watering, keeping grass somewhat tall, and bagging lawn clippings to prevent contamination of previously infected areas. Healthy grass then returns once the infection is cleared. Using a fungicide before infection serves as a preventative measure. Dollar Spot: Dollar spot thrives in the middle of paper...... his illness. American-Lawns.com suggests controlling this disease by applying a fungicide in October or early March, after which heavy watering is necessary. The onset of warm weather kills infected grass.Stripe Smut: This cool weather turf disease is usually not serious and thrives in temperatures of 50 to 60 degrees. It cannot appear in prolonged hot temperatures of around 90 degrees. Striped smut affects grass growth, giving lawns a patchy, uneven appearance. Infected slides have yellowish-green streaks that eventually turn gray and black. The black streaks rupture, splitting the leaves and releasing black powdery spores. John Swenson suggests preventing the progression of Stripe Smut by applying nitrogen and watering thoroughly, preferably in the morning. Severe cases, although rare, require the use of a fungicide in late fall or early spring..