Clarireedia jacksonii
Dollar Spot (Clarireedia jacksonii) is a serious fungal disease affecting Kentucky Bluegrass, Bermudagrass, Zoysia, Perennial Ryegrass, Creeping Bentgrass. It triggers under warm days (70°f–85°f), cool nights with heavy dew, low soil moisture, and nitrogen-deficient turf. Symptom manifestation begins with individual leaf blades show bleached hourglass lesions with distinct reddish-brown borders. white cobwebby mycelium visible in morning dew. Curative control requires Propiconazole, Myclobutanil (Eagle 20EW), or Boscalid.
Connect with certified lawn pathologists and licensed pesticide applicators in your ZIP code.
Curative treatment of Dollar Spot requires strict adherence to statutory EPA product label directions. University extension trials demonstrate high efficacy with the following commercial chemistries:
Broad-spectrum systemic strobilurin (Azoxystrobin, FRAC 11) for curative and preventative control of turf fungi.
Check Price on Amazon →High-potency organophosphate (Dylox / Trichlorfon) curative halting subterranean insect damage within 24 hours.
Check Price on Amazon →Pathogen virulence operates strictly under the classic Plant Disease Triangle: infection requires an active pathogen inoculum, a genetically susceptible turfgrass host, and conducive microclimatic conditions (primarily prolonged leaf canopy moisture exceeding 10 consecutive hours combined with elevated rootzone humidity). Unmown or excessively dense turf stands impede airflow, creating an insulated stagnant microclimate where fungal spore germination accelerates.
When evaluating suspect turf patches, cross-examine rootzone integrity against foliar discoloration. True root-rot pathogens compromise subterranean anchoring, allowing turfgrass mats to be pulled up effortlessly with zero tensile resistance. In contrast, foliar blights damage leaf blades while leaving crown tissue and primary adventitious roots viable for regenerative recovery once fungicide active ingredients are introduced.
Cultural Protocol: Apply light spoon-feedings of quick-release nitrogen. Irrigate deeply in early morning to knock down dew. Always avoid excess evening irrigation; irrigate early between 4:00 AM and 8:00 AM to allow rapid sun-drying of turf foliage. Keep cutting blades sharp to minimize ragged blade wounds through which fungal hyphae penetrate.
Chemical Protocol: Propiconazole, Myclobutanil (Eagle 20EW), or Boscalid. Rotate active ingredients across different FRAC / IRAC mode-of-action groups (such as rotating Group 11 strobilurins with Group 3 triazoles) to prevent resistant fungal strains from dominating your lawn ecosystem.
Dollar Spot is recognized by Bleached straw-white or silver patches resembling silver dollars. forming 1 to 3 inches on close-cut turf; up to 6 inches on residential lawns.. Blade symptoms: Individual leaf blades show bleached hourglass lesions with distinct reddish-brown borders. White cobwebby mycelium visible in morning dew.
Primary susceptible hosts include Kentucky Bluegrass, Bermudagrass, Zoysia, Perennial Ryegrass, Creeping Bentgrass. Maintaining proper fertilization and irrigation reduces pathogen virulence.
Extension-recommended treatment: Propiconazole, Myclobutanil (Eagle 20EW), or Boscalid. Active ingredient: Propiconazole (Group 3) & Myclobutanil (Group 3).
Apply light spoon-feedings of quick-release nitrogen. Irrigate deeply in early morning to knock down dew.
