Red Thread-Resistant Grasses

Red thread is a fungal disease which kills turf grass. This fungus covers a huge area without killing the grass since it spreads, but after 2- to 8-inch-wide regions of dead grass appear. Look for a reddish-pink jelly-like webbing, which glues the grass blades together. In areas prone to crimson thread illness, plant crimson thread-resistant grass varieties.

Susceptible Varieties

Some turf grasses are prone to red thread strikes. These grasses include cultivars of bentgrass, bluegrass, fescue, ryegrass and Bermuda grass. Infestations occur more often along coastal areas in which the temperatures are light, between 60 and 75 degrees Fahrenheit. Long periods of dampness also raise red thread development.


Perennial ryegrass (Lolium spp.) Is a tough native North American grass commonly planted for agricultural functions like livestock grazing. This vigorous grass produces green stalks, narrow leaves and summer flowers in U.S. Department of Agriculture plant hardiness zones 1 through 12. In zones with warm summer weather, this grass variety does not survive the heat and is employed as a winter annual. Even though ryegrass is vulnerable to red thread fungus, enhanced perennial varieties demonstrate strong immunity to the respiratory disorder. According to the University of Illinois Extension, the following varieties comprise “Birdie II,” “Citation II,” “Linn,” “Pennant,” “Pippin,” “Premier” and “Tara.”

Fine-Leaf Fescue

Fine-leaf fescue (Festuca spp.) Grows best as a cool-season continued grass. Suited for USDA zones 1 through 9, this grass seems like a clumping or creeping narrow-blade grass forming a dense lawn. Many fescue grasses perish from crimson thread infections, but a few new varieties are immune to this disease. Resistant or reasonably resistant fine-leaf fescue grasses comprise “Atlanta,” “Aurora,” “Bighorn,” “Biljart,” “Dawson,” “Epsom,” “Flyer,” “Golfrood,” “Reliant,” “Scaldis,” “Shadow,” “Spartan,” “Valda,” “Weekend” and “Wintergreen.”

Kentucky Bluegrass

Kentucky bluegrass (Poa pratensis) is a cool season grass that grows best in fall, winter and spring in USDA zones 1 through 8. The green grass blades produce a dense turf. Recently developed Kentucky bluegrass cultivars show good levels of immunity to crimson thread. The University of Illinois Extension reports which “Adelphi,” “Admiral,” “Aspen,” “Banff,” “Barblue,” “Bonnieblue,” “Bono,” “Bristol,” “Classic,” “Dormie,” “Eclipse,” “Haga,” “Harmony,” “Holiday,” “Midnight,” “Nassau,” “Trenton” and “Welcome” are immune to red thread.

See related