Common Name: red thread
Scientific Name: Laetisaria fuciformis

Red thread develops in circular or irregular patches from 4 inches to 2 feet in diameter. Affected leaves within these patches are tan or bleached-white in color. From a distance, the patches usually have a reddish appearance, due to the presence of thick, red strands of fungal growth emanating from the affected leaves. It is through production of these “red threads” that the fungus spreads to healthy plants and survives unfavorable conditions. Small tufts of pink, fuzzy mycelium may also be present in or around the patches when the leaves are wet or humidity is high. After prolonged periods of disease development, the patches may merge to produce large irregularly shaped areas of damaged turf.
red thread mycelium and sclerotia
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Characteristic Description
Host Turfgrass (1)Kentucky bluegrass, tall fescue, fine fescue, perennial ryegrass
Month(s) with symptomsMarch to June, September to December
Stand Symptoms (8)spots, circles, patches (4 to 12 inches)
Foliar Symptoms - Location/Shape (1)dieback from leaf tip, blighting of entire leaves
Foliar Symptoms - Color (3)red, pink, tan
Root/Crown Symptomsnone
Fungal Signs (6)thread-like sclerotia
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