What Disease Does My Lawn Have
What disease does my lawn have? It's the right question when patches look sick—but not every brown or yellow spot is a disease.
Brown patch, dollar spot, rust, and other fungi leave clues, yet drought, grubs, and pet damage can mimic disease from the sidewalk.
Treating the wrong problem wastes a season; you need the pattern in your yard, not a generic bag at the store.
Upload a photo and get an exact diagnosis in seconds
Common causes
Brown patch fungus
Large tan or brown circles and rings that spread after warm, humid nights—often in mid to late summer.
Dollar spot
Small bleached spots about the size of a silver dollar that merge into patchy damage on stressed turf.
Red thread or rust
Pinkish threads on blades or orange dust on shoes—common in cool, wet stretches when grass is underfed.
Pythium and wet-weather blight
Greasy, dark, or fast-spreading damage in low spots after heavy rain or too much evening watering.
Grub and insect damage
Not a disease, but grass pulls up like carpet—easy to mistake for fungus until you check roots.
Drought and heat stress
Dry soil browns turf without fungus—watering more on these patches won't fix what looks like 'sick' grass.
How to identify the issue
Compare these three clues before you treat:
- Color
Tan rings often suggest brown patch. Bleached silver-dollar spots point to dollar spot. Pink threads or orange dust mean red thread or rust.
- Spread pattern
Rings that grow outward each week differ from random drought fade or grub patches that pull up—growth speed matters.
- Location
Humid low areas, thick thatch, shady damp zones, and overwatered strips each favor different problems—not all are fungal.
Not sure which one this is?
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Quick fixes
- Look at blades at dawn—slimy or webby grass plus spreading rings suggests active fungus, not drought.
- Pull gently at patch edges; carpet-like lift means check for grubs before you spray fungicide.
- Water deeply in the morning, not at night—wet blades overnight invite many lawn diseases.
- Avoid blanket fungicide until you match the spot pattern; wrong sprays don't help drought or grubs.
- Upload a photo before buying disease products—visual pattern beats guessing from a shelf label.