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Turfgrass Diseases. Turfgrass Disease. Disease : normal development disturbed; reduces value. Turfgrass Disease. Symptom : visible reaction to a disease. Turfgrass Disease. Abiotic : non-living causes. Turfgrass Disease. Abiotic : Herbicide. Turfgrass Disease. Abiotic : Scalping.
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Turfgrass Disease • Disease: normal development disturbed; reduces value
Turfgrass Disease Symptom: visible reaction to a disease
Turfgrass Disease Abiotic: non-living causes
Turfgrass Disease Abiotic: Herbicide
Turfgrass Disease Abiotic: Scalping
Turfgrass Disease Abiotic: Dull Mower
Turfgrass Disease Abiotic: Nutrient
Turfgrass Disease Abiotic: Fertilizer
Turfgrass Disease Abiotic: Cold
Turfgrass Disease Biotic: living organisms, infectious • Fungus…
Environment Temperature • Fungus in the host unnoticed until the host is under stress
Environment Moisture • Rain • Dew • Irrigation • Poor drainage is critical
CULTURAL CONTROL DRAINAGE! • Most important
CULTURAL CONTROL Disease-resistant turf • Correct species or resistant cultivar
CULTURAL CONTROL Diversify the genetic resistance • Blends: mixing cultivars of a species • Mixes: mixing species of turf
CULTURAL CONTROL Proper turfgrass establishment • At least 6” of topsoil • Properly graded with good drainage
CULTURAL CONTROL Mowing • Mow within correct height • Good cut
CULTURAL CONTROL Irrigation • Avoid irrigating in the evening • Early morning to knock off the dew • Deeply and infrequently
CULTURAL CONTROL Nutritional status • Influences diseases • Excessive N favors Pythium and Brown Patch
CULTURAL CONTROL Nutritional status • Deficient N favors Dollar Spot and Rust
CULTURAL CONTROL Nutritional status • Potassium helps environmental stress • Use K in a the same proportions as N
CULTURAL CONTROL Thatch control • Thatch can support some diseases
BIOLOGICAL CONTROL None used commercial with great success
FUNGICIDE Preventative: applied prior to favorable conditions at lower rates Curative: applied after symptoms have occurred at higher rates
FUNGICIDE Contacts: form preventative coating
FUNGICIDE Contacts • New leaves have no protection • Fungicide degrades under irrigation, sunlight, mowing • Effective for 7 to 14 days
FUNGICIDE Contacts • Broad spectrum controls mostly foliar diseases and not root/crown diseases
FUNGICIDE Penetrant • Protective and curative • Effective for 15 to 30 days
FUNGICIDE Penetrant • Specific MOA, develops resistant strains • Some chemicals are mixes to take advantage of both the contact and systemic effects
Brown Patch Causal Agent: Rhizoctonia
Brown Patch Hosts: zoysia, St. Augustine, centipede
Brown Patch Favorable Conditions: • Spring and fall months • Start watching in August
Brown Patch Symptoms: • Smoke ring on greens • No leaf spots, leaf sheath rot at base
Brown Patch Symptoms: • Shoots pull off from stolons easily • Roots not affected
Brown Patch Controls: • Avoid excess N • Improve drainage
Gray Leaf Spot Host: St. Augustine
Gray Leaf Spot Favorable Conditions: • Mid-July • Shade
Gray Leaf Spot Symptoms: • All aboveground plant parts
Gray Leaf Spot Control: • Collect clippings • Raise mowing height
Dollar Spot Host: bermuda, zoysia
Dollar Spot Favorable Conditions: • Warm weather, 60 to 80 F • Low N • Thatch
Dollar Spot Symptoms: • Leaf lesions band across leaf with purple border
Dollar Spot Symptoms: • White patches in dew • fungus
Dollar Spot Control: • Apply N
Dollar Spot Control: • Apply N
Fairy Rings Causal Agent: fungi