TURFGRASS DISEASES

Algal Scum Symptoms on Turf
Algae do not infect turfgrasses but they are highly invasive and often out-compete grasses for space in wet or shaded environments. Algal scum can be a chronic problem on greens, especially those with poor air circulation, compacted soils and wet areas. Their growth is encouraged by extended periods of rainy, overcast and warm weather.

Anthraconose Symptoms on Turf
Anthracnose may kill plants in irregularly shaped patches from several inches to many feet in diameter. The overall color of affected patches goes from reddish brown to tan.
Submitted 09/1996

Bentgrass Disease Index

Bermuda Decline

Bipolaris, Drechslera and Exserohilum Leaf Spot, Crown and Root Rot Symptoms on Turf
Helminthosporium type diseases develop during warm weather when cyclical patterns of wetting and drying occur in the thatch layer. Symptoms often appear on leaf blades (leaf spots) in cool weather and as crown and root rots (melting-out) in hot humid weather.
Submitted 09/1996

Brown Patch

Brown Patch Symptoms on Turf
The name, brown patch, is not very descriptive of the varied symptom expression caused by Rhizoctonia spp. on turfgrass. Symptoms differ on cool- and warm-season grasses and vary depending on environmental conditions and cultural practices.
Submitted 09/1996

Buffalo Grass Disease Index

Centipede Grass Disease Index

Common Bermuda Disease Index

Disease Control Recommendations

Dollar Spot

Dollar Spot - Small Brown Patch Symptoms on Turf
Bentgrass, hybrid bermudagrasses and zoysiagrass are most susceptible to dollar spot.
Submitted 09/1996

Downy Mildew
Leaf blades have white or yellow-green linear streaks running parallel to the leaf veins. Leaves turn yellow and there may be some browning of leaf tips.
Submitted 09/ 1996

Fairy Ring Sysmptoms on Turf
Fairy rings grow in circles or crescent-shaped areas, ranging from a few inches to 50 feet in diameter, feed on organic matter in the soil and thatch layer.
Submitted 09/1996

Fescue Disease Index

Fungicide Group Classification

Gray Leaf Spot

Gray Leaf Spot Symptoms on Turf
Gray leaf spot develops rapidly with abundant moisture and warm temperatures on St. Augustinegrass.
Submitted 09/1996

Hybrid Bermuda Disease Index

Necrotic Ring Spot

Necrotic Ring Spot Symptoms on Turf
Circular patches over a foot in diameter appear in the spring, fade with warmer temperatures and then reappear with heat and drought stress.

Nematode Symptoms on Turf
Affected areas appear yellow and thin, and do not respond to watering or fertilizing. Nematodes feed on turfgrass roots which prevents absorption of water and nutrients.
Submitted 09/1996

Perennial Ryegrass Disease Index

Pink Snow Mold
Pink snow mold occasionally is a problem during extended periods of cool, wet weather with or without ice or snow cover. Patches occur as reddish-brown spots ranging from an inch to several inches in diameter. Sometimes a pink fungal mycelium may be seen at the advancing edge of the spot.

Poa sp. Disease Index

Powdery Mildew

Powdery Mildew Symptoms on Turf
Powdery mildew is especially common on annual grasses used for overseeding. It spreads rapidly in shaded areas.

Pythium Blight

Pythium Blight, Cottony Blight, Greasy Spot Symptoms on Turf
Disease is favored during rainy, foggy weather and in low lying areas where air circulation is poor. Roundish, dark, greasy to slimy patches of matted grass, from two to 12 inches in diameter, appear suddenly.

Red Thread

Rust Symptoms on Turf
Bluegrass, ryegrass and zoysiagrass are most commonly affected. Rust diseases are favored by warm humid conditions and develop most frequently on grasses stressed by drought conditions, low nitrogen fertility and shade.
Submitted 09/1996

Seedling Disease Symptoms on Turf
Seedling blight kills the young plants either before or just after emergence, resulting in a reduced stand. Post-emergence attacks cause the seedlings to collapse and die soon after emergence.

Slime Molds

Slime Mold Symptoms on Turf
Dark gray-to-black crust-like material will form on the leaves and stems of turfgrass. The soot-type material rubs off easily on shoes and clothing.
Submitted 09/1996

Snow Mold - Gray

Snow Mold - Pink

Spring Dead Spot

Spring Dead Spot Symptoms on Turf
When turf begins regrowth in early spring, well-defined circular dead spots become evident. Individual spots may range in size from a few inches to several feet in diameter and are usually depressed.

St. Augustine Decline

St. Augustine Decline Symptoms on Turf
In early infection stages, leaves show a chlorotic (yellow) mottling. The mottling or mosaic symptom becomes progressively more severe until a chlorotic appearance is observed. In later stages of disease development, leaves and stolons begin to die and invading grasses and weeds crowd out weakened St. Augustine or Centipede grass. Infected grass does poorly in shaded areas.
Submitted 09/1996

St. Augustine Disease Index

Stripe Smut

Smut Symptoms on Turf
Smut galls replace seed in the spike. The inflorescence (flower) is often distorted.

Summer Patch Symptoms on Turf
Initially, summer patch resembles dollar spot but patches quickly grow and affect large areas of turf. Affected areas may appear dark green initially and then reddish-brown to bronze colored.

Take-All Patch

Take-all Root Rot, Take-all Patch, Bermuda Decline Symptoms on Turf
Take-all root rot fungus is active in fall and winter when there is abundant moisture and moderate temperatures.
Submitted 09/1996

Zoysiagrass Disease Index