What Are These Red Worm-Like Things in My Lawn?

Red Thread

• Red thread is a common fungal disease of many different species of turfgrass, particularly Bentgrasses, bluegrasses, fescues, ryegrasses and bermudagrasses. Caused by the pathogenic fungus Laetisaria fuciformis, red thread earns its name because its most conspicuous symptoms are red or pink, thread-shaped, worm-like growths that break out on the tops of the grass stalks. These threads are fruiting bodies (called sclerotia) of the causal fungal organism.

Symptoms

• The appearance of the red threads themselves indicates that the red thread disease has already reached an advanced stage of infection, so in order to protect the health of your grass, it is essential to recognize the earliest symptoms of the disease. Irregular patches of dead, tan-colored grass break out over your lawn. As the disease progresses, these patches take on a slightly red or pink hue when viewed from a distance. These patches often also have a gelatinous or water-soaked appearance just before the threads themselves break out of the grass shoots.

Natural Controls

• Natural control measures begin with planting a species of grass that is known to be less susceptible to infection by red thread disease, particularly if you live in the temperate, wet climates that favor the disease. Nitrogen deficiencies in grass also appear to contribute to red thread infection, so keep your grass well fertilized. Even though periods of prolonged leaf wetness contribute to infection, keeping your lawn irrigated will help prevent red thread infection as well.

Chemical Controls

• Generally speaking, fungicides are not recommended for red thread control except in the most extreme cases. Infected grasses almost always outgrow red thread damage. If use of a fungicide is warranted, however, strobilurin and flutolanil fungicides are very effective at controlling the disease. Always follow manufacturer's labeled application instructions exactly to avoid any unintended harm to your turfgrass as a result of fungicide injury.