Powdery Mildew

What it looks like

A white-to-gray powder covering the grass blades, almost like flour or chalk dust, that rubs off easily if you touch it. It shows up only in shaded parts of the lawn. Don't confuse it with dew or frost sitting on the grass, or with gray leaf spot, which causes tan-bordered spots rather than a powdery coating.

Often mistaken for: Dew or frost residue; gray leaf spot

When it shows up in the Triangle

Shows up spring through fall in the Triangle, anywhere Kentucky bluegrass or fine fescue is growing in persistent shade with poor air movement.

Where you’ll see it

Affects Kentucky bluegrass and fine fescue lawns growing in shaded areas.

What you can do

• Prune or thin trees and shrubs overhead to let in more light and improve airflow — this is the real fix
• If you can't reduce the shade, overseed with a more shade-tolerant fine fescue
• Avoid over-fertilizing with nitrogen, since it makes the grass more prone to this problem
• Mow regularly and avoid letting grass stay damp and shaded for long periods