Lawn Disease – Gray Leaf Spot

(Pyricularia grisea)

Gray Leaf Spot – is a potentially destructive turfgrass disease that occurs in most areas of the eastern United States where perennial ryegrass is grown. This disease affects northern climates from late summer through the fall and affects southern climates primarily in the summer months. Gray Leaf Spot often develops in drought prone areas.      

Identifying Gray Leaf Spot -

Gray Leaf Spot first appears as small, brown spots on the leaves and stems. These spots quickly enlarge and become bluish-gray in color and oval shaped. Older lesions are tan to gray in color and depressed in the center. The margins are purple to brown in color and irregularly shaped. Damage from this turfgrass disease quickly transitions from small, inconspicuous leaf spots to completely dead areas of turf.

Symptoms of Gray Leaf Spot in your lawn can vary significantly depending on the species of turfgrass being infected.

Conditions for Gray Leaf Spot Infection -

Gray Leaf Spot can only lead to an infection in your lawn if all of the following conditions are present:

1. Pathogen – Gray Leaf Spot (Pyricularia grisea)

2. Host – Centipedegrass, Perennial ryegrass, St. Augustinegrass or tall fescue

3. Environment – Hot, humid climates with temperatures ranging from 80-90 degrees Fahrenheit and compact soils with high nitrogen levels

Gray Leaf Spot Control -

Cultural disease control practices create favorable conditions for a healthy lawn, and often create unfavorable conditions for the growth of Gray Leaf Spot. Environmental conditions cannot be changed, but cultural practices performed by the homeowner can be modified to lessen the chance of extensive damage from Gray Leaf Spot. Scotts LawnService can help determine a plan for preventing and controlling Gray Leaf Spot in your lawn.

For Gray Leaf Spot control and treatment, Scotts LawnService recommends the following cultural control tips:

  • Avoid fertilizers with excessive levels of nitrogen in the middle of summer
  • Infrequent deep watering is recommended verses frequent shallow watering
  • Reduce shade and increase air flow to reduce the amount of time the water is left on the leaf blades
  • Reduce thatch with core aeration or vertical cutting
  • Plant disease resistant turfgrass varieties

Scotts LawnService has professional products that can prevent and control lawn diseases when cultural control practices are not effective.

Scotts LawnService is the trusted industry leader for professional quality lawn care. Our exclusive lawn care products include premium grass seeds, professional-grade fertilizers and professional products to control lawn diseases; our lawn service teams are comprised of highly trained, industry-certified professionals. Contact a representative today for Gray Leaf Spot control options available in your area and to learn how you can enjoy a lush, thicker lawn that only Scotts LawnService can deliver.