South Florida, especially Palm Beach County, is famous for its beautiful, lush lawns. However, maintaining that perfect green carpet isn’t always easy, thanks to persistent fungal diseases that thrive in our tropical climate. If you’re noticing patches, discoloration, or other troubling signs in your lawn, there’s a good chance fungi are to blame. In this comprehensive guide, we’ll walk you through identifying, treating, and preventing the most common lawn fungal diseases found in Palm Beach County.
1. Large Patch (Rhizoctonia Solani)
Symptoms: Expansive, circular brown patches with distinct yellow-orange edges. Affected areas can exceed several feet in diameter.
Causes: Typically occurs during cooler, damp periods, often exacerbated by excessive nitrogen fertilization and poor drainage.
Treatment and Prevention:
- Avoid overwatering and excess nitrogen fertilizer, particularly in cooler months.
- Improve drainage by aerating regularly.
- Apply fungicides like azoxystrobin or fluoxastrobin proactively in early spring and late fall.
Take our quiz!
Lawn Disease ID Quiz
Loading…
2. Take-all Root Rot (Gaeumannomyces Graminis)
Symptoms: Turf appears yellow, thin, and patches pull up easily, revealing dark, rotten roots.
Causes: High soil pH, poor drainage, heavy thatch accumulation, and frequent watering.
Treatment and Prevention:
- Adjust soil pH to around 6.0–6.5 using sulfur amendments.
- Regularly aerate and top-dress with compost.
- Preventive fungicides (azoxystrobin) applied at the first sign of disease.
3. Rust (Puccinia spp.)
Symptoms: Grass blades exhibit reddish-orange pustules that easily rub off on hands, shoes, or lawn equipment.
Causes: Shady, moist environments with poor airflow, and lawns under stress from lack of nutrients.
Treatment and Prevention:
- Increase fertilization to encourage robust growth.
- Maintain proper mowing heights to reduce grass stress.
- Fungicide treatments with triazoles or strobilurins for severe cases.
4. Dollar Spot (Clarireedia Jacksonii)
Symptoms: Small, round tan-colored spots roughly the size of silver dollars, often merging into larger affected areas.
Causes: Low fertility, drought stress, and leaf moisture from dew or irrigation.
Treatment and Prevention:
- Fertilize adequately to improve turf health.
- Deep, infrequent watering in the early morning.
- Use preventive fungicide treatments like thiophanate-methyl or propiconazole.
5. Hydrophobic Fairy Ring
Symptoms: Rings or arcs of dark-green or dead grass, sometimes accompanied by mushrooms due to a water-repellent fungal mat beneath.
Causes: Excessive organic matter, dense thatch, and compacted soils.
Treatment and Prevention:
- Core aerate the affected area to break through the fungal layer.
- Apply wetting agents to allow water penetration.
- Severe cases benefit from fungicides such as azoxystrobin.
6. Gray Leaf Spot (Pyricularia Grisea)
Symptoms: Gray or tan leaf spots with distinct dark margins, especially prevalent during the hot, humid summer.
Causes: Excessive nitrogen fertilization, humidity, and poor air circulation.
Treatment and Prevention:
- Limit nitrogen applications during peak summer.
- Increase airflow by pruning trees and shrubs.
- Fungicide treatments with azoxystrobin or pyraclostrobin if persistent.
7. Cercospora Leaf Spot (Cercospora Fusimaculans)
Symptoms: Narrow, elongated purple-to-tan spots on leaf blades, often with dark brown borders.
Causes: Low mowing heights, drought stress, and compacted soils.
Treatment and Prevention:
- Mow grass at recommended heights.
- Ensure regular watering practices to minimize drought stress.
- Fungicide treatments like thiophanate-methyl as needed.
8. Bipolaris Leaf Spot (Bipolaris Sorokiniana)
Symptoms: Purple to reddish-brown lesions, especially noticeable during drought conditions.
Causes: Drought stress, nutrient deficiencies, and improper lawn maintenance.
Treatment and Prevention:
- Improve lawn nutrition through balanced fertilization.
- Implement consistent irrigation practices.
- Fungicide treatments with azoxystrobin or iprodione if cultural controls fail.
9. Slime Mold
Symptoms: Superficial crusty, powdery growth in shades of gray, yellow, or purple on the grass surface.
Causes: Excessive moisture, humidity, and shaded conditions.
Treatment and Prevention:
- Simply brush or rinse off the mold; chemical treatments are unnecessary.
- Improve sunlight exposure and air circulation.
10. Pythium Root Rot (Pythium spp.)
Symptoms: Turf thinning and discoloration with noticeably rotted, blackened roots.
Causes: Poor drainage, frequent irrigation, and shaded, humid conditions.
Treatment and Prevention:
- Enhance soil drainage and reduce watering frequency.
- Apply fungicides containing mefenoxam in persistent cases.
Expert Help is Just a Call Away
If fungal diseases continue to challenge your lawn or you’d like expert preventive care, Floridist is ready to help. Our specialized lawn care experts in Palm Beach County offer comprehensive soil testing, customized treatment plans, and proven preventive strategies to keep your lawn looking its absolute best.
Don’t let fungal problems ruin your beautiful lawn. Contact Floridist today and let our experienced team provide the professional, effective care your lawn deserves.