Helminthosporium Leaf Spot / Melting Out

What it looks like

Small purple-to-brown spots with tan centers on the grass blades. As it progresses, the lawn can thin out and die in patches as the roots and crowns get damaged, especially in lawns mowed too short or growing in shade.

Often mistaken for: Other leaf spot diseases or general summer heat/drought stress thinning

When it shows up in the Triangle

Shows up during cool, wet spells in spring and fall here in the Triangle. The worst thinning (melting out) often becomes obvious once summer heat stresses grass that was already weakened by spring infection.

Where you’ll see it

Affects home lawns of tall fescue and Kentucky bluegrass.

What you can do

• Mow a bit higher rather than scalping the lawn
• Avoid heavy nitrogen feeding in spring, which encourages lush, susceptible growth
• Water only in the morning so grass isn't wet overnight
• Improve air flow by pruning back shrubs or trees shading the lawn
• Consider reseeding with more resistant tall fescue varieties over time