WSU Extension


Lawn and Turf
2,4-D damage 
Anthracnose/Basal crown rot 
Brown blight 
Brown patch 
Curvularia blight (Fading out) 
Dog injury 
Dollar spot 
Fairy ring and mushrooms 
Leaf spot 
Microdochium patch (Pink snow mold) 
Necrotic ringspot 
Powdery mildew 
Pythium crown and root rot 
Red thread 
Septoria leaf spot (Tip blight) 
Slime molds 
Take-all patch 
Typhula blight (Gray snow mold) 
Yellow patch 
Chinch bugs 
European Chafer 
European crane fly 
Japanese beetle 
Japanese beetle 
Sod webworm 

print version| pdf version| email url    
Caption: Powdery mildew
Photo by: R.S. Byther
Lawn and Turf : Powdery mildew
(revision date: 6/22/2015)

Powdery mildew is a fungal disease affecting the leaf blades. Bluegrasses and fescues are the most commonly affected lawn grasses. Blades and sheaths of older leaves are covered with mats of fine, white or grayish fungal mycelia on the upper surfaces. Under favorable conditions, the fungus can spread rapidly and become quite dense. Infected leaves turn yellow, then tan to brown, and die back. Severe infections can kill grass plants or can weaken them to such a degree that other factors such as cold can kill the plants. Conditions favoring disease development include cool, humid, cloudy weather and heavily shaded lawns. The fungus survives primarily in infected plants.
Management Options

Non-Chemical Management
  • When using Kentucky bluegrass, plant mixtures of improved varieties.
  • Do not plant grass in heavily shaded areas.
  • When practical, prune trees and shrubs to reduce shading and improve air circulation.
  • Provide proper culture, including adequate, balanced fertilization and deep, infrequent watering.
  • Water grass in the morning so it can dry quickly.
  • Mow grass regularly at the recommended height.
  • For more information on proper care of lawns, including mowing heights and fertilizer recommendations, see EB0482E, Home Lawns.
Select non-chemical management options as your first choice!

Chemical Management

Not recommended for home lawns.


+ Show larger images

Caption: Powdery mildew
Photo by: R.S. Byther