GOLF - TURFGRASS DISEASES - INFORMATION CHART



LAWN TURFGRASS DISEASE – INFORMATION CHART

Remember the main reasons for brown grass are adverse weather, poor soils and improper maintenance. The table addresses infectious diseases caused by fungal pathogens.

Joseph W. Rimelspach & Todd E. Hicks — Department of Plant Pathology / The Ohio State University

|DISEASE NAME |SUSCEPTIBLE GRASS |SIGNS & |ENVIRONMENTAL FACTORS | * MANAGEMENT STRATEGIES |

| |(All capital letters indicate most common |SYMPTOMS |(Temperature & Moisture conditions that favor disease | |

|(Pathogen name, |affected.) |(Signs are the fungus or a part of the fungus, symptoms|development.) |(This is the first line of defense and tool to manage disease. After these |

|the fungus) | |are the result of the infection on the plant, abnormal | |have been implemented and depending on the circumstances then fungicide |

| | |appearance or growth.) | |applications may be considered.) |

|Brown Patch/ |TALL FESCUE |- Irregular to circular patches (6”-2’) |Hot/Wet |Avoid excessive Nitrogen fertilization, esp. in summer. |

|Rhizoctonia Blight |PERENNIAL RYEGRASS |- Patches variable shades of tan to brown |Days > 80 to mid 90s and warm nights, mid 60s +. |Avoid excessive watering & poor drainage. |

|(Rhizoctonia solani) |BENTGRASS |- Outer edges of patch may be darker |Abundant water, wet soils. |Increase air circulation by removing surrounding vegetation & increase sun |

| |Kentucky bluegrass |- Irregular shaped lesions on leaves |High humidity, at night and/or days. |light. |

| |Fine Fescue |- Gray to white fungal growth may be present when turf|Lawns with shade or partial shade. |Manage to prevent lush succulent turfgrass plants. |

| |(JUVENILE TURF PLANTS) |wet and high humidity |Sites with limited air movement. |Lower mowing height of tall fescue to increase drying. |

| | |- May be confused with Pythium blight |Cloudy, slow drying conditions. |Select more resistant cultivars to the disease. |

|Dollar Spot |BLUEGRASS |- Circular tan patches/spots (1-6”) |Moderate days 60 to low 80s |Avoid fertility deficiencies especially Nitrogen. |

|(Sclerotinia homoeocarpa) |BENTGRASS |- Leaf lesions light tan with dark edges |Prolonged periods of wet leaves. |Choose a more resistant grass species. |

| |Fine Fescues |- Leaf lesions go across leaf blade (a band) |Dry Soil – results in slow growth and poor recovery |Manage watering to minimize time leaves are wet. |

| |Perennial Ryegrass |- White fungal growth may be present in early morning |from damage by disease. |Water to increase growth if soil is dry. |

| |Tall Fescue |when dew present. |High humidity in turf canopy. |Select more resistant cultivars to the disease. |

|Fairy Ring |All Turfgrasses |- Dark green or brown circles (1-10+’) |Grow over a wide range of temps. And soil moisture |Improve water penetration; aeration, deep watering, and wetting agents. |

|(Soil borne Basidiomycete fungi) | |- Grass in dark green ring may grow taller |conditions, often favored by moist soils. Brown turf |Increase fertilization to “mask green rings”. |

| | |- Rings may turn brown and die |may develop in prolonged hot dry periods. |Remove infected soil and replace with clean soil & sod or seed the area. |

| | |- Mushrooms may grow in the ring |May be seen in all seasons. |Renovate the lawn by rototilling up the soil. |

| | |- A white fungal mat may be present in the thatch area | | |

| | |of the ring and smells musty | | |

|Gray Leaf Spot |PERENNIAL RYEGRASS |- Starts as v. small dark spots/flecks |Prolonged hot humid weather patterns in late summer and|Plant resistant varieties or avoid perennial ryegrass. |

|(Magnaporthe oryzae) |Tall fescue (in S.E. USA) |- Leaves often quickly wither and die |fall, long summer stress conditions for cool season |Avoid lush turfgrass, use moderate fertilization. |

| |St. Augustinegrass (in S. USA) |- Irregular patches to large areas die |grasses. Moist soils, (turf may appear wilted as from |Manage watering to minimize time leaves are wet. |

| | |- Only P. ryegrass affected, other grasses and weeds |drought but soil is moist). |Use resistant grass species, i.e. Kentucky bluegrass.. |

| | |are not affected | |Minimize turf stress; reduce compaction, avoid chemical injury (herbicides). |

| | |- No fungus (mold) is found on plants | | |

|Leaf Spot/Melting Out |KENTUCKY BLUEGRASS |- Initially very small dark spots on leaves |Usually in Cool/Wet conditions but can also occur in |Raise cutting height. |

|(Drechsler & Bipolaris spp.) |(Common bluegrasses) |- Spots enlarge in size |Moderate & Warm temps. |Mow frequently to avoid stressing turf. |

| |Fine fescue |- Center of spots may be a lighter brown |- there are many different leaf spots |Avoid excessive nitrogen. |

| |Perennial Ryegrass |- Can be quite variable in color and shape |Melting Out/Hot Dry |Avoid frequent watering and wet turf. |

| |Tall fescue |- Leaf sheaths can be entirely infected |(Leaf Spot: spring & fall, |Select more resistant cultivars to the disease. |

| | |- Crowns rot, turf thins (“melting out”) |Melting Out: summer) | |

| | | | | |

|DISEASE NAME |SUSCEPTIBLE GRASS |SIGNS & |ENVIRONMENTAL FACTORS |* MANAGEMENT STRATEGIES |

|(Pathogen name) | |SYMPTOMS | | |

|Powdery Mildew |KENTUCKY BLUEGRASS |- White or gray colored powdery appearance to leaf |Moderate/High humidity |1) Reduce shade. |

|(Erysiphe graminis) |Fine Fescue |surface (does not easily rub off) |Shade |2) Increase air circulation |

| | |- Leaves may yellow and turf stand thin |Areas of poor air circulation. |3) Use resistant Kentucky bluegrass varieties. |

|Pythium Blight |PERENNIAL RYEGRASS |- May start as small dead spots |V. Hot/Wet |Improve soil drainage. |

|(Pythium species) |BENTGRASS |- Leaves often look dark/black/greasy |(This is a water mold, abundant water is required.) |Increase air circulation by removing surrounding vegetation. |

| |Kentucky bluegrass |- Fluffy gray to white ‘cottony’ fungus may be present|(Days high 80s to 90s ++ and warm nights 70 and above.)|Avoid excess watering. |

| |(JUVENILE TURF PLANTS) |when disease is active |Often found in low wet areas, with poor drainage. |Avoid high rates of Nitrogen and lush growth. |

| |(Rather uncommon on mature high cut |- Spots may run together and have an irregular shape, | |New seedling often affected in hot wet conditions |

| |turfgrasses) |turf quickly dies, brown | | |

| | |- May be confused with brown patch | | |

|Red Thread |PERENNIAL RYEGRASS |- Patches appear as tan, light pink or reddish |Moderate/Wet Foliage |Follow a complete fertilization program, avoid deficiencies in nitrogen and |

|(Laetisaria fusiformis) |FINE FESCUE |- Leaf tips and edges of leaves have fine pink or red |Prolonged periods of wet leaves. |phosphorous. |

| |Kentucky bluegrass |strains of fungus present |Poor quality soil. |Promote growth by aeration, proper watering, etc. |

| |Tall Fescue & Bentgrass |- Size of patches variable (2-12”) | |Use more resistant cultivars. |

|Rust |PERENNIAL RYEGRASS |- Starts as small yellow flecks on leaves |Moderate/Wet Foliage, Dry Soil |Avoid fertility deficiencies especially Nitrogen. |

|(Puccini species) |KENTUCKY BLUEGRASS |- Flecks enlarge, to form rust colored raised spots |(Dry Soil – slow leaf growth so poor recovery from |Use resistant varieties of Kentucky bluegrass & perennial ryegrass or turf |

| |(Some varieties of Key bluegrass are |(pustules, spores rubs off on shoes…) |damage.) |type tall fescues. |

| |susceptible, some resistant) |- Over all turf yellows and thins |Poor quality soil, compacted soils. |Water if dry, promote growth. |

| | | | |If soil compacted aggressively core aerate. |

| | | | |Improve poor soils by topdressing with compost. |

|Slime Mold |All Turfgrasses |- Small pin head size balls/ debris on leaves, vary in |Moderate to warm temperatures/ |Mechanically remove by raking or mowing. (Causes no injury, only cosmetic.) |

|(Myxomycete species) | |color yellow, white, gray, purple, etc |Prolonged wet foliage | |

| | |- Cosmetic problem , rubs off leaves | | |

|Snow Mold / Pink |CREEPING BENTGRASS |- Infected grass in patches, bleached, matted |Cool wet winters. |Avoid lush turf going into winter, keep mowing to prevent long grass going |

|(Microdochium nivale) |Perennial Ryegrass |- Grass appears slimy when wet |Saturated, unfrozen, soil for long periods is ideal for|into winter. |

| |Kentucky bluegrass |- Patches may run together to form large irregular |development. |Rake and remove leaves. |

| | |affected areas |No snow required. |Control drifting snow, prevent piles of snow. |

| | |- Crowns are often alive for recovery. |Occurs in winter and spring. |Provide adequate drainage, surface and subsurface. |

|Summer Patch |KENTUCKY BLUEGRASS |- Begins as dark wilted spots like drought stress |Warm/Extremes in soil moisture (Fluctuating wet to dry)|Avoid low mowing & thatch buildup. |

|(Magnaporthe poae) |Fine fescue |(1-3”) and enlarge to patches |Poor quality soil, compacted, clay, buried stone and |Aggressively core aerate 2-3 + time per year. |

|& | |(about 12’ in diameter) |debris etc… |(pull 10 - 12 core per sq. ft.) |

|Necrotic Ring Spot | |- Shapes are variable, crescents, streaks etc. – Outer |Usually occurs on sodded lawns with poor site |Water frequently to avoid water stress. |

|(Ophiosphaerella korrae) | |edge of circles/patches are brown with green centers |preparation (the turf has a weak or limited root |Use very slow-release fertilizer. |

| | |are common. |system). |Renovate the damaged areas with resistant grasses, |

|These are Patch Diseases | |- Crowns and roots usually die. | |such as p. ryegrass or turf tall fescue but may not blend. |

| | | | |Maintain soil pH between 6 & 7. |

* For fungicide recommendations check the web site below or check with the county cooperation extension officer and State Land Grant University in your area.

For additional information look under publications at - turfdisease.osu.edu Expanded Turf_Dis_Chart 01.22.2018)

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