Short Course - Diseases of TurfLane Tredway & Lee ButlerDept. of Plant PathologyNorth Carolina State University
What is a disease?An abnormality in structure or functioncaused by a long-term association with an infectious agentthat in...
Turfgrasses are Susceptible to Disease when STRESSED
Some diseases caused widespread damage in a           short period of time...
...others might reduce the uniformity of a playing surface...
...others may reduce the aesthetic appearance of the turf.
Injury is caused by humans or non-living factors.
Three factors are required for disease to develop                        t                    en                  nm      ...
Five types of microorganisms cause disease      Fungi (1X)                            Nematodes (400X)                    ...
Number of Known Diseases by Pathogen Type                          Mycoplasmas                Viruses     Bacteria   Nemat...
Percent of Turf Problems by Pathogen Type       Nematodes                           Fungi
Nematode ClassificationNematodes are grouped by type of symptom induced, or uniquecharacteristic of nematode      • Sting  ...
The sting nematode is most damaging to turfgrasses.
Nematode damage is more severe in sandy soils.
Reduction of root depth is the most obvious symptom of nematode injury.
Diseases attack the turf in different locations                                             Foliar Diseases:              ...
Mycology 101: Key Characteristics of Fungi• need water or high humidity to grow• grow and cause disease in a narrow temper...
Most pathogens are facultative saprophytes, surviving in the thatch              and soil when not causing disease
Hyphae are the basic vegetative structure of most fungi.
Masses of hyphae, visible to the naked eye, are called mycelium.
Many fungi also produce spores.
Some fungi produce spores directly on the leaf surface, whileothers produce them inside of special structures.
The Environment Triggers Disease Development• Weather – temperature, rain, humidity, dew, sunlight,  day length• Microclim...
The Environment Triggers Disease Development• Temperature and water are the most important factors  influencing disease dev...
The Environment Triggers Disease DevelopmentFoliar diseases are triggered by low night temperature   • Dollar Spot - >50ºF...
The Environment Triggers Disease DevelopmentRoot diseases are triggered by soil temperature   • Summer Patch - > 65ºF   • ...
Diagnosis of Turfgrass Diseases
“Textbook Symptoms”
Turfgrass diseases can appearvery similar.Which is gray leaf spot andwhich is Pythium blight?
Many turfgrass problemsappear very similar from adistance.
Herbicide injury can appearvery similar to a disease.Which is large patch andwhich is herbicide injury?
How to Tell the Difference???
Why is Accurate Diagnosis Important?  •   Essential for prompt and effective problem      management  •   Incorrect diagno...
Turfgrass Disease Diagnosis: A process of elimination  1. Start with a list of possibilities based on turf species and tim...
RE     MI                      CE RE CR                        NT CE OC                          CU NT LIM                ...
Stand SymptomsSymptoms evident from a distance   Spots – less than 4” diameter   Patches – irregularly shaped areas greate...
SPOT   DOLLAR SPOT
SPOT
SPOT
PATCH   BROWN PATCH
PATCH
PATCH
RING   SUMMER PATCH
RING
RING
IRREGULAR   RUST
IRREGULAR
Plant SymptomsSymptoms evident on individual plantsLeaf Spot – round or oval areas on leaves with a distinct borderFoliar ...
LEAF SPOT   GRAY LEAF SPOT
LEAF SPOT
LESION   BROWN PATCH
LESION
STEM LESIONS   LARGE PATCH
FOLIARBLIGHT
CROWN ROT   NECROTIC RING SPOT
CROWN ROT
ROOT ROT   SUMMER PATCH
Pathogen SignsEvidence of Pathogen Growth Mycelium – weblike masses of fungal growth Spore Masses – fuzzy or gelatinous gr...
MYCELIUM   PYTHIUM BLIGHT
MYCELIUM
MYCELIUM
SMOKE RING
SPORE MASSES
FRUITING BODIES   ANTHRACNOSE
FRUITING BODIES
SCLEROTIA   RED THREAD
SCLEROTIA   SOUTHERN BLIGHT
MUSHROOMS
NC State Turf Diagnostics Lab
Digital Images of Turf Problems
Summer Diseases of Tall FescuePythium blight                                               Brown patch                    ...
Brown Patch (Rhizoctonia solani)
BROWN PATCH
BROWN PATCH
Conditions Favoring Disease•   Extended periods of hot/humid weather•   Most severe when daily low/high is above 70/90 res...
Brown Patch Resistance in Tall Fescue Cultivars                       1996 NTEP Trial, Lexington KY     KENTUCKY-31       ...
Brown Patch Control• All of the labeled fungicides control brown  patch effectively• Products differ in “residual control”...
Residual Control of Brown PatchQoIs – 21 to 28 daysDicarboxamides – 14 to 21 daysCarboxamides – 14 to 21 daysBenzimidazole...
Cost Analysis – Brown Patch ControlProduct         Rate (oz/1000 ft2)   Cost per lb   Cost per 1000 ft2Insignia 20WG      ...
Gray Leaf Spot (Pyricularia grisea)
GRAY LEAF SPOT
GRAY LEAF SPOT
Conditions Favoring Disease• Most devastating first year of establishment• Temperatures between 70 and 95 F• 14 hours of co...
Pythium blight (Pythium aphanidermatum)
Pythium blightTall fescue
PYTHIUM BLIGHT OF TALL FESCUE
PYTHIUM BLIGHT OF TALL FESCUE
Conditions Favoring Disease• Low temperatures above 65°F• 12-14 or more hours of leaf wetness or high  relative humidity• ...
Conditions Favoring Dollar Spot• Low temperatures >50°F• High temperatures <95°F• 10 consecutive hours of leaf wetness• Lo...
Dollar spot is most severe in under-fertilized turf.
Seed SizeTall Fescue vs. Kentucky Bluegrass   Tall Fescue       Kentucky Bluegrass 500 seeds/gram      4,800 seeds/gram
Mixing Ratios and Seed Numbers  Tall Fescue vs. Kentucky BluegrassMix Ratio   Tall Fescue   Kentucky Bluegrass(TF:KBG)    ...
Kentucky bluegrass can become                           dominant in a short period of time…                               ...
Tall FescueKentucky bluegrass
Questions?
2011 Short Course
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2011 Short Course

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NC State University Turfgrass Short Course
02/17/2011

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2011 Short Course

  1. 1. Short Course - Diseases of TurfLane Tredway & Lee ButlerDept. of Plant PathologyNorth Carolina State University
  2. 2. What is a disease?An abnormality in structure or functioncaused by a long-term association with an infectious agentthat injures the plant or reduces its economic value
  3. 3. Turfgrasses are Susceptible to Disease when STRESSED
  4. 4. Some diseases caused widespread damage in a short period of time...
  5. 5. ...others might reduce the uniformity of a playing surface...
  6. 6. ...others may reduce the aesthetic appearance of the turf.
  7. 7. Injury is caused by humans or non-living factors.
  8. 8. Three factors are required for disease to develop t en nm Ho o st vir Disease En Pathogen
  9. 9. Five types of microorganisms cause disease Fungi (1X) Nematodes (400X) Bacteria (2,500X) Mollicutes (25,000X) Viruses (36,000X)
  10. 10. Number of Known Diseases by Pathogen Type Mycoplasmas Viruses Bacteria Nematodes Fungi
  11. 11. Percent of Turf Problems by Pathogen Type Nematodes Fungi
  12. 12. Nematode ClassificationNematodes are grouped by type of symptom induced, or uniquecharacteristic of nematode • Sting • Lesion • Lance • Ring • Stubby root • Spiral • Cyst • Root knot
  13. 13. The sting nematode is most damaging to turfgrasses.
  14. 14. Nematode damage is more severe in sandy soils.
  15. 15. Reduction of root depth is the most obvious symptom of nematode injury.
  16. 16. Diseases attack the turf in different locations Foliar Diseases: Copper spot Bipolaris & Drechslera leaf spots Brown patch Dollar spot Gray leaf spot Gray snow mold Stripe smut Pink patchStem and Crown Pink snow moldDiseases: Powdery mildewAnthracnose basal rot Pythium blightAlgae Red threadBentgrass dead spot RustsLarge patch Southern blightMelting out Yellow tuftWhite patch Root diseases: Bermudagrass decline Necrotic ring spot Pythium root dysfunction Pythium root rot Spring dead spot Summer patch Take-all patch
  17. 17. Mycology 101: Key Characteristics of Fungi• need water or high humidity to grow• grow and cause disease in a narrow temperature range• ubiquitous - they are everywhere!• primary role in nature is decomposition• some able to use a living plant as a food source
  18. 18. Most pathogens are facultative saprophytes, surviving in the thatch and soil when not causing disease
  19. 19. Hyphae are the basic vegetative structure of most fungi.
  20. 20. Masses of hyphae, visible to the naked eye, are called mycelium.
  21. 21. Many fungi also produce spores.
  22. 22. Some fungi produce spores directly on the leaf surface, whileothers produce them inside of special structures.
  23. 23. The Environment Triggers Disease Development• Weather – temperature, rain, humidity, dew, sunlight, day length• Microclimate – shade, air movement, soil type, drainage, traffic• Management – mowing, fertilization, irrigation, cultivation
  24. 24. The Environment Triggers Disease Development• Temperature and water are the most important factors influencing disease development• Foliar Diseases – low night temperature, leaf wetness duration• Root and Crown Diseases – soil temperature, soil moisture
  25. 25. The Environment Triggers Disease DevelopmentFoliar diseases are triggered by low night temperature • Dollar Spot - >50ºF • Brown Patch – >60ºF • Pythium blight - >65ºF
  26. 26. The Environment Triggers Disease DevelopmentRoot diseases are triggered by soil temperature • Summer Patch - > 65ºF • Take-all Patch - 40ºF to 60ºF • Spring Dead Spot - 60ºF to 80ºF • Large Patch - <70ºF
  27. 27. Diagnosis of Turfgrass Diseases
  28. 28. “Textbook Symptoms”
  29. 29. Turfgrass diseases can appearvery similar.Which is gray leaf spot andwhich is Pythium blight?
  30. 30. Many turfgrass problemsappear very similar from adistance.
  31. 31. Herbicide injury can appearvery similar to a disease.Which is large patch andwhich is herbicide injury?
  32. 32. How to Tell the Difference???
  33. 33. Why is Accurate Diagnosis Important? • Essential for prompt and effective problem management • Incorrect diagnoses cost TIME and MONEY, and may result in further turf damage • New generation of fungicides and insecticides control a smaller number of diseases or pests
  34. 34. Turfgrass Disease Diagnosis: A process of elimination 1. Start with a list of possibilities based on turf species and time of year 2. Look for clues 3. Rule out diseases, narrow the list of possibilities 4. Repeat steps 2 and 3 5. Send sample to a diagnostic lab
  35. 35. RE MI CE RE CR NT CE OC CU NT LIM LT WE AT Diagnosis Triangle UR AT E, AL HE PR R, AC TIC ES PL DIAGNOSIS AN TA NDSIGNS OF PATHOGEN ST AN D SY PT M OM S
  36. 36. Stand SymptomsSymptoms evident from a distance Spots – less than 4” diameter Patches – irregularly shaped areas greater than 4” diameter Circles – perfectly circular areas greater than 4” diameter Rings – surrounded by healthy turf to the inside and outside Irregular – no pattern
  37. 37. SPOT DOLLAR SPOT
  38. 38. SPOT
  39. 39. SPOT
  40. 40. PATCH BROWN PATCH
  41. 41. PATCH
  42. 42. PATCH
  43. 43. RING SUMMER PATCH
  44. 44. RING
  45. 45. RING
  46. 46. IRREGULAR RUST
  47. 47. IRREGULAR
  48. 48. Plant SymptomsSymptoms evident on individual plantsLeaf Spot – round or oval areas on leaves with a distinct borderFoliar Lesions – large, irregular areas on leaves with a distinct borderStem Lesions – large, irregular areas on leaf sheaths with a distinct borderFoliar blight or dieback – necrosis of leaves or entire tillersCrown Rot – necrosis of the crown, rhizomes, or stolonsRoot Rot – necrosis of the roots
  49. 49. LEAF SPOT GRAY LEAF SPOT
  50. 50. LEAF SPOT
  51. 51. LESION BROWN PATCH
  52. 52. LESION
  53. 53. STEM LESIONS LARGE PATCH
  54. 54. FOLIARBLIGHT
  55. 55. CROWN ROT NECROTIC RING SPOT
  56. 56. CROWN ROT
  57. 57. ROOT ROT SUMMER PATCH
  58. 58. Pathogen SignsEvidence of Pathogen Growth Mycelium – weblike masses of fungal growth Spore Masses – fuzzy or gelatinous growth Fruiting Bodies – spore producing structures Sclerotia – small, round or thread-like survival structures Mushrooms – reproductive structures produced by fairy ring fungi
  59. 59. MYCELIUM PYTHIUM BLIGHT
  60. 60. MYCELIUM
  61. 61. MYCELIUM
  62. 62. SMOKE RING
  63. 63. SPORE MASSES
  64. 64. FRUITING BODIES ANTHRACNOSE
  65. 65. FRUITING BODIES
  66. 66. SCLEROTIA RED THREAD
  67. 67. SCLEROTIA SOUTHERN BLIGHT
  68. 68. MUSHROOMS
  69. 69. NC State Turf Diagnostics Lab
  70. 70. Digital Images of Turf Problems
  71. 71. Summer Diseases of Tall FescuePythium blight Brown patch Gray leaf spot Immature turf is more susceptible to these destructive diseases!
  72. 72. Brown Patch (Rhizoctonia solani)
  73. 73. BROWN PATCH
  74. 74. BROWN PATCH
  75. 75. Conditions Favoring Disease• Extended periods of hot/humid weather• Most severe when daily low/high is above 70/90 respectively• 10-12 hours continuous leaf wetness• Poor water management• Excessive nitrogen• Perfect recipe ... repeating afternoon thunderstorms after dry spell • Front porch rule
  76. 76. Brown Patch Resistance in Tall Fescue Cultivars 1996 NTEP Trial, Lexington KY KENTUCKY-31 JAGUAR 3 REBEL 2000 WOLFPACK PLANTATION CHAPEL HILL ARID RENEGADE APACHE II MUSTANG IIFALCON III (MB 212) TAR HEEL FALCON II COCHISE IISOUTHERN CHOICE SHORTSTOP II COYOTE BONSAI TOMAHAWK-E CORONADO 0 5 10 15 20 % Brown Patch
  77. 77. Brown Patch Control• All of the labeled fungicides control brown patch effectively• Products differ in “residual control”, or the number of days of control• For tall fescue, application intervals can be extended by 7 to 14 days
  78. 78. Residual Control of Brown PatchQoIs – 21 to 28 daysDicarboxamides – 14 to 21 daysCarboxamides – 14 to 21 daysBenzimidazoles – 10 to 14 daysDMIs – 7 to 10 daysContacts – 7 to 10 daysPolyoxin D – 7 to 10 days
  79. 79. Cost Analysis – Brown Patch ControlProduct Rate (oz/1000 ft2) Cost per lb Cost per 1000 ft2Insignia 20WG 0.5 $111 $3.49Heritage TL 1 $576 (gal) $4.50Banner Maxx 2 $289 (gal) $4.52Heritage 50WG 0.2 $356 $4.56Compass 50WG 0.25 $300 $4.69Prostar 70WP 1.5 $52 $4.88Insignia 20WG 0.7 $111 $4.88Bayleton 50DF 1 $81 $5.06SysStar 80WDG 2.25 $44 $6.19Insignia 20WG 0.9 $111 $6.28Prostar 70WP 2.25 $52 $7.17Heritage TL 2 $576 (gal) $9.00Heritage 50WG 0.4 $356 $9.12
  80. 80. Gray Leaf Spot (Pyricularia grisea)
  81. 81. GRAY LEAF SPOT
  82. 82. GRAY LEAF SPOT
  83. 83. Conditions Favoring Disease• Most devastating first year of establishment• Temperatures between 70 and 95 F• 14 hours of continuous leaf wetness• Excessive nitrogen• Heavy rains will promote rapid spread of spores due to splashing effect ... as will mowing
  84. 84. Pythium blight (Pythium aphanidermatum)
  85. 85. Pythium blightTall fescue
  86. 86. PYTHIUM BLIGHT OF TALL FESCUE
  87. 87. PYTHIUM BLIGHT OF TALL FESCUE
  88. 88. Conditions Favoring Disease• Low temperatures above 65°F• 12-14 or more hours of leaf wetness or high relative humidity• High nitrogen levels• Poor surface or subsurface drainage• High soil pH (above 7.0)
  89. 89. Conditions Favoring Dollar Spot• Low temperatures >50°F• High temperatures <95°F• 10 consecutive hours of leaf wetness• Low nitrogen and other nutrients• Low mowing height• Excessive thatch accumulations
  90. 90. Dollar spot is most severe in under-fertilized turf.
  91. 91. Seed SizeTall Fescue vs. Kentucky Bluegrass Tall Fescue Kentucky Bluegrass 500 seeds/gram 4,800 seeds/gram
  92. 92. Mixing Ratios and Seed Numbers Tall Fescue vs. Kentucky BluegrassMix Ratio Tall Fescue Kentucky Bluegrass(TF:KBG) Seeds (#) Seeds (#) 90:10 204,000 218,000 95:5 216,000 109,00097.5:2.5 221,000 54,000
  93. 93. Kentucky bluegrass can become dominant in a short period of time… %TF in 1999 90:10 %TF in 2002TF:KBG seed by weight 95:5 97.5:2.5 100:00 10.0 32.5 55.0 77.5 100.0 % Tall Fescue
  94. 94. Tall FescueKentucky bluegrass
  95. 95. Questions?

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