Dollar Spot Disease: Identification and Treatment

Dollar spot is caused by Clarireedia jacksonii (formerly classified as Sclerotinia homoeocarpa) and is one of the most common turfgrass diseases in North America.

Dollar spot is caused by Clarireedia jacksonii (formerly classified as Sclerotinia homoeocarpa) and is one of the most common turfgrass diseases in North America. The name comes from the symptom pattern on closely mowed turf — small, roughly circular tan spots about the size of a silver dollar. On home lawns maintained at 3—4 inches, the spots can be larger, but the characteristic hourglass lesion on individual blades is diagnostic.

Identification

Patch symptoms

Per Penn State Extension's turfgrass disease guide, dollar spot patches on home lawns appear as tan to straw-colored spots ranging from 2 to 6 inches in diameter. Multiple spots may coalesce under heavy disease pressure into larger irregular areas of dead turf.

Unlike brown patch, the patches of dead turf in dollar spot are typically small and numerous — a lawn with heavy dollar spot looks like it's peppered with silver-dollar-sized tan circles. Brown patch produces fewer, much larger patches.

Leaf blade symptoms

The most reliable identification feature is the leaf lesion. Per NC State Extension TurfFiles, dollar spot lesions on individual blades are:

• Bleached or straw-colored in the center
• Bordered by reddish-brown to tan bands at both ends
• Hour-glass shaped when viewed on an intact blade — the lesion narrows across the width of the blade and widens again above and below
• Present throughout the patch, not just at edges

This "hourglass" or "banded" lesion distinguishes dollar spot from brown patch (which causes tip blight with a chocolate brown irregular margin) and from other diseases.

Mycelium in the morning

Per Penn State Extension, dollar spot produces a white, cottony mycelium visible on the grass surface during morning dew — similar to brown patch but finer textured and present throughout the patch area rather than at the advancing edge. The mycelium disappears as the dew evaporates. Look for it early in the morning before 9 a.m.