All turfgrass species, but Kentucky
bluegrass and perennial
ryegrass are most susceptible
Leaf surfaces are covered with a grayish white powdery growth. Isolated
patches may spread to larger areas of the lawn. Leaf blades may turn
pale yellow in later stages of the disease.
Conditions favoring disease
Cool temperatures (about 65°F), high humidity, and poor air
circulation favor the development of powdery mildew. The disease
is most severe in shady areas.
Prevention and management
Reduce shade and improve soil aeration.
In areas where powdery mildew is a problem, plant less susceptible
species. Follow proper irrigation and fertilization
recommendations for your turf species. Mow at the high end of
the recommended height for
your species. Fungicides are usually not warranted.
For more information on lawn diseases, refer to:
Pest Notes: Lawn Diseases:
Prevention and Management