Gray Leaf Spot

What it looks like

Round or oval tan spots with dark brown edges that turn gray and fuzzy when it's humid. On fescue and ryegrass, it can show up as 4-12 inch orange-yellow, greasy-looking matted patches, which can look a lot like a different disease called pythium blight.

Often mistaken for: Pythium blight

When it shows up in the Triangle

Shows up here from July through September, especially during hot, humid stretches when temps sit between 70-95°F and grass stays wet for long periods overnight.

Where you’ll see it

Affects tall fescue, perennial ryegrass, zoysiagrass, and St. Augustinegrass lawns, with new lawns (planted within the past year) at the highest risk.

What you can do

• Water early in the morning so grass doesn't stay wet all night
• Improve air flow by trimming back overgrown shrubs or thinning dense areas
• Mow at the right height for your grass type and never cut more than a third of the blade at once
• Skip heavy fertilizing in late spring and summer
• Keep an eye on new lawns during hot, humid weather since they're the most vulnerable