How to Identify Lawn Fungus

Identify Rings, Spots and Patches

• 1

  Look for pink or gray patches when the snow melts. This common fungus, snow mold, occurs mostly with fescues and Kentucky grass. It's also named typhula blight and fusarium patch.

• 2

  Check for rhizoctonia blight, with 1 to 3 feet circular patches. Formerly called brown patch, this fungus appears in hot weather. In humid weather, it has a smoke ring at the edge colored gray or purple.

• 3

  Find tan or straw colored spots that appear as cobwebs and you've identified dollar spot. The webs appear with early dew in humid areas. Bluegrass has a 4 to 6 inch circular spot with up to 23 inch areas in bent grass.

• 4

  Notice brownish colored rings or crescents of dying grass with green centers and you have fusarium blight. It likes Kentucky bluegrass in hot and dry conditions.

• 5

  Detect dark greasy looking spots 1 to 6 inches wide and it's probably pythium blight. This fungus thrives in hot, humid weather and appears water soaked.

• 6

  Observe blades having spots turning purple with brown borders. Common with bluegrass, Leaf Spot appears in warm weather. It moves downward killing the grass and often extends in irregular patches across the lawn.

• 7

  Watch for necrotic ring spot in early spring and fall. A brown and red colored ring forms giving a frog-eye appearance.

Identify Blobs and Distortions

• 8

  Discover bleached looking areas that turn to pink. Red thread prefers fescues and rye blends in cool and humid weather. In wet conditions, the grass develops red threads near the tops.

• 9

  Watch for mushrooms growing in the fairy ring. These rings expand each year. Good growth surrounds the inner dead area.

• 10

  Observe small blobs of yellow or gray slime on the turf during high humidity and rain. This slime mold eventually turns a powdery gray, blue or white color.

• 11

  Look for white powdery mildew in areas with poor air circulation, humidity and shade. Leaves turn yellow in dense shade.

• 12

  Detect orange and brown pustules emerging from blades in hot, humid weather. When mowing the lawn a reddish-orange dust rises from the grass. It mostly affects low maintenance lawns.