Turfgrass Disease Identification

Many diseases occur on the turfgrasses that are used throughout North Carolina. Most of the diseases included here are caused by fungi. Some problems that resemble diseases are caused by environmental or management factors such as cold, heat, drought, high soluble salts, soil compaction, or chemical damage. Careful identification of the cause of a problem is important for the selection of proper control methods.


HOW TO USE THIS PROGRAM

  • Select the Turfgrass type (host turf) that is affected.
  • Select the Month(s) the grass is affected.
  • Additional tabs with disease criteria will become available
  • As you choose disease criteria and click on Submit button the disease list (on right) will change. The changes in the list reflect the diseases appropriate to your selection(s)

Host Turf & Months

Knowing the type of turfgrass affected by the disease is the first step in diagnosis. Once you have selected your turfgrass below, click on 'Month(s) with Symptoms' above to continue selecting criteria.

Host Turfgrass
bentgrass, creeping
bermudagrass
bluegrass, annual
bluegrass, Kentucky
bluegrass, rough
centipedegrass
fescue, fine
fescue, tall
ryegrass, perennial
St. Augustinegrass
zoysiagrass
Month(s) with Symptoms
January
February
March
April
May
June
July
August
September
October
November
December
Diseases
Stand Symptoms

Stand symptoms - are most easily observed by standing and looking across the turf area. There are several different types of stand symptoms, which basically describe the pattern of the disease on the lawn or landscape. Diseases may produce:

Spots - localized areas of diseased turf less than 4 inches in diameter.

Circles - localized areas of damage that are perfectly circular and greater than 4 inches in diameter.

Patches - localized areas of damage that are irregularly shaped and greater than 4 inches in diameter.

Rings - circular areas of diseased turf with healthy turf to the inside and outside, leaving a ring-like pattern on the turf stand.

Irregular symptoms - non-patterned symptoms across the turf stand

Stand Symptoms
spots
circles
patches, 4 to 12 inches in diameter
patches, 1 to 3 feet in diameter
patches, greater than 3 feet in diameter
rings
irregular distribution across turf stand
Foliar Symptoms

Foliar symptoms - the location and shape of foliar symptoms can provide valuable clues in the diagnosis of turf diseases. There are several different types of foliar symptoms, which basically describe the pattern of the disease on the leaf. Generally, the best leaf symptoms can be observed along the border between healthy and diseased turf. The plants in severely affected areas that are already dead are not very useful for diagnosis of turfgrass diseases. Diseases may produce:

Leaf Spot - round or oval area on the leaf with a distinct border, which is usually a different color than the center of the spot.

Leaf Lesion - irregular in shape and typically larger than a leaf spot, but still has a distinct border that is usually a different color.

Lesion on Leaf Sheath - very similar to a leaf lesion, but is present on the leaf sheath of the grass plant rather than on the leaves.

Blighting of Entire Leaves - symptoms cover whole leaves and produce a distinct border between healthy and diseased turf.

Dieback from Leaf Tip - symptoms cover whole leaves, as they do for blighting, but they do not produce a distinct border between healthy and diseased turf.

Foliar Symptoms - Location/Shape
round or oval leaf spots
angular leaf spots
leaf lesions
dieback from leaf tip
blighting of entire leaves
lesions on leaf sheaths
no distinct leaf symptoms
Foliar Symptoms - Color
tan
brown
black
gray
white
yellow
orange
red
pink
purple
Root/Crown Symptoms

Root/crown symptoms - certain diseases attack the roots, crowns, rhizomes or stolons of the turf plant and cause symptoms on these tissues. Diseases may produce:

Crown Rot - a dark and rotten area at the base of the turfgrass plant.

Root Rot - a visibly dark and rotten root system, and also a noticeable reduction in root depth in affected areas.

Generally, the best plant symptoms can be observed along the border between healthy and diseased turf. The plants in severely affected areas that are already dead are not very useful for diagnosis of turfgrass diseases. Crown rots and root rots often occur together, and may also include rotting of stolons and rhizomes, if present.

Root/Crown Symptoms
dark brown or black
roots tan and lacking root hairs
no visible symptoms
Fungal Signs

Fungal signs - the visible evidence of the presence of a pathogen. Most turfgrass diseases are caused by fungi, and even though fungi are microscopic organisms, some produce larger structures at certain times in their life cycle that can be seen with the naked eye. Diseases may produce:

Mycelium - a cottony or spider-web-like mass of fungal growth that certain fungi produce when the turf is wet or humidity is high.

Spore Masses - fuzzy or jelly-like growths produced on the diseased tissue by certain fungi, again usually when the turf is wet or humidity is high.

Pustules on Leaves - small, spherical structures produced on the leaf surfaces, that contain fungal spores.

Blisters on Leaves - raised areas of leaf tissue that change color and then rupture to release powdery masses of fungal spores.

Fruiting Bodies - structures of various shapes and sizes that release fungal spores. Usually dark in color and embedded in the diseased plant tissue. May be found on all above- and below-ground parts of the turf plant.

Sclerotia - small, round, or threadlike structures produced on the diseased turf or in the thatch layer by certain fungi

Puffballs - A spherical spore-producing structure up to 3" in diameter produced on the turf surface. Similar to a mushroom, but lacking a stem or stalk.

Mushrooms - Spore-producing structures with a cap and stem produced on the turf surface by Basidiomycete fungi.

Fungal Signs
none visible
blisters on leaves
mushrooms present
mycelium
puffballs present
pustules on leaves
sclerotia, round
sclerotia, thread-like
spore masses, fuzzy
spore masses, jelly-like
spore masses, powdery
spores in acervuli with setae