Red Thread
Red Thread is a lawn disease caused by a fungus and tends to appear mostly in the spring and early summer. When there are extended periods of rainy, humid, wet conditions with temperatures around 65° to 75°F, red thread can develop. It is usually associated with perennial ryegrass, fine fescue, and Kentucky bluegrass lawns but can appear in regular lawn grasses. Red thread is one of the most common lawn diseases in Pennsylvania and frequently occurs with another disease called pink patch, which has similar symptoms. When lawns do not receive adequate amounts of nitrogen fertilizer and are weak, sick, or malnourished they have more difficulty fighting off infections. Red thread acquires its name from the red and pink cast areas of lawn which grow in circular or irregularly shaped patches. Diseased areas eventually dry out and fade to a light, bleached straw color.

Lawn Management
Although red thread can look troubling, it is mostly a cosmetic problem. While it can temporarily damage sections of your lawn, it is rarely totally destructive. Planting a resistant grass variety will help reduce the threat of red thread taking over your lawn. Be aware, this lawn fungus is easily spread by your lawn mower. By washing your mower after each mowing, the chances of spreading it are reduced.

Treatment
Red thread will eventually grow itself out without any treatment in about two weeks once the ground dries out. Fungicide could be used; but it is not necessary. A week of warm weather and dry conditions will impede the growth of this lawn disease. While Showcase LawnWorks doesn’t recommend fungus treatments for red thread in regular cases, if it is warranted, a treatment plan of two applications administered 28 days apart can help eliminate this lawn disease problem.