Combatting Lawn Diseases: Identification and Prevention Strategies

I’ve seen just about every lawn disease you can imagine. The dry summers, cold winters, and fluctuating spring conditions in our state create the perfect storm for lawn issues, especially fungal diseases. If you’re a Utah homeowner trying to keep your lawn green and healthy, understanding these threats is key.

In this post, I’m going to walk you through the most common lawn diseases we see here in Utah. I’ll break down how to identify them, what causes them, and, most importantly, how to prevent and treat them. Whether you’re dealing with a spotty yard or want to stop problems before they start, this guide will help.

Why Lawn Disease Happens in Utah

Utah lawns face unique environmental challenges that make them vulnerable to disease:

• Snowy winters: Snow cover can trap moisture and create ideal conditions for snow mold.
  
  
• Drought-prone summers: Heat-stressed grass is more likely to get infected.
  
  
• Clay-heavy soil: Poor drainage can lead to fungal outbreaks.
  
  
• Cool, wet springs and falls: These conditions are perfect for fungal spores to thrive.
  
  

If you’re noticing brown patches, rings, or thinning grass, you might be facing a lawn disease. Let’s break down the top offenders.

1. Snow Mold

Snow mold is one of the most common lawn diseases in Utah, especially after a heavy winter.

What Causes It:

• Prolonged snow cover (over 60 days)
  
  
• Wet, matted grass
  
  
• Late fall fertilizing with high-nitrogen fertilizers
  
  

How to Spot Snow Mold:

• Circular patches of matted, straw-colored grass
  
  
• Gray or pink fuzz in early spring
  
  
• Grass feels slimy or wet
  
  

Prevention Tips:

• Mow your lawn short before the first snow
  
  
• Rake leaves and debris in the fall
  
  
• Avoid heavy nitrogen fertilizer late in the season
  
  
• Aerate your lawn to improve airflow
  
  

Treatment:

• Rake and dry out affected areas
  
  
• Overseed if the grass doesn’t recover
  
  
• Apply a fungicide if the infection is severe
  
  

2. Necrotic Ring Spot (NRS)

Necrotic Ring Spot is a serious fungal disease that affects Kentucky bluegrass, which is common in Utah lawns.

What Causes It:

• Fungus Ophiosphaerella korrae
  
  
• Compacted soil and poor drainage
  
  
• Overwatering or shallow watering
  
  

Signs of Necrotic Ring Spot:

• Circular or crescent-shaped dead patches
  
  
• Rings with healthy green grass in the center ("frog-eye" pattern)
  
  
• Patches appear in late spring or early summer
  
  

Prevention Tips:

• Aerate your lawn annually
  
  
• Water deeply but infrequently (2-3 times per week)
  
  
• Apply balanced fertilizers (avoid excess nitrogen)
  
  
• Use resistant grass varieties if possible
  
  

Treatment:

• Core aeration and topdressing with compost
  
  
• Fungicide treatments in spring and fall
  
  
• Regular overseeding to fill in bare spots
  
  

3. Leaf Spot (Melting Out)

Leaf Spot is another common disease in Utah, especially during cool, wet spring months.

What Causes It:

• Fungal pathogens like Drechslera or Bipolaris
  
  
• Wet, humid conditions
  
  
• Over-fertilizing and mowing too short
  
  

How to Spot It:

• Purple or brown spots on grass blades
  
  
• Grass thins and dies off in large patches
  
  
• Affects Kentucky bluegrass, perennial rye, and fescues
  
  

Prevention:

• Water early in the day to allow drying
  
  
• Raise your mowing height
  
  
• Avoid high nitrogen in early spring
  
  

Treatment:

• Apply fungicides if caught early
  
  
• Reduce lawn stress with proper watering and mowing
  
  
• Reseed affected areas with disease-resistant grass
  
  

4. Red Thread

Though not as severe as others, Red Thread is unsightly and common in Utah’s springtime lawns.

What Causes It:

• Low nitrogen levels
  
  
• Cool, damp weather
  
  

Symptoms:

• Pink or red thread-like structures on grass blades
  
  
• Patches of tan or pink grass, 4–8 inches wide
  
  
• Grass recovers slowly
  
  

Prevention:

• Maintain balanced nitrogen levels
  
  
• Aerate compacted soil
  
  
• Improve drainage
  
  

Treatment:

• Apply nitrogen fertilizer to help grass outgrow the disease
  
  
• Reseed with resistant varieties
  
  
• Fungicides usually not necessary
  
  

5. Dollar Spot

Dollar Spot is a summer lawn fungus that shows up in small, round patches.

What Causes It:

• High humidity and low nitrogen
  
  
• Poor air circulation
  
  
• Consistent wetness from frequent watering
  
  

How to Identify It:

• Silver-dollar-sized tan spots
  
  
• Grass blades have a bleached-out appearance with a dark band
  
  
• Spots can merge into larger patches
  
  

Prevention:

• Water deeply and less frequently
  
  
• Fertilize moderately
  
  
• Improve air movement and mow regularly
  
  

Treatment:

• Spot treat with fungicide
  
  
• Reduce lawn stress
  
  
• Keep mower blades sharp to avoid damage
  
  

How to Spot Lawn Disease Early

The sooner you catch a lawn disease, the easier it is to fix. Here are some red flags to watch for:

• Unusual color changes (yellow, brown, pink)
  
  
• Patches or rings of dead grass
  
  
• Sticky, slimy, or fuzzy textures
  
  
• Slow-growing or thinning areas
  
  

When in doubt, take a close-up photo and send it to a local lawn care expert, like us at Lawn Thumbs.

Lawn Fungus Treatment: What Works and What Doesn’t

Some myths float around about lawn fungus treatments. Here’s what I’ve found works best after years in the Utah turf game:

What Works:

• Fungicides: Use as a last resort, and follow label directions closely
  
  
• Proper watering: Water in the morning, not at night
  
  
• Fertilization: Balanced feeding keeps grass strong
  
  
• Aeration: Reduces compaction and improves airflow
  
  

What Doesn’t:

• Over-fertilizing: More is not always better
  
  
• Watering at night: Traps moisture and feeds fungus
  
  
• Mowing too short: Weakens the grass and exposes soil
  
  

Prevention: Your Best Line of Defense

If you take one thing from this guide, let it be this: prevention is way easier (and cheaper) than treatment. Here’s a simple seasonal plan that works well for Utah lawns:

Spring:

• Aerate and overseed
  
  
• Apply pre-emergent weed control
  
  
• Start a regular mowing schedule
  
  

Summer:

• Water deeply, 2–3 times per week
  
  
• Fertilize lightly with a slow-release mix
  
  
• Mow higher during heatwaves
  
  

Fall:

• Aerate and dethatch
  
  
• Apply a balanced fertilizer
  
  
• Rake leaves before snow sets in
  
  

Winter:

• Clear snow buildup in shady areas
  
  
• Avoid walking on frozen grass
  
  

When to Call a Professional

If your lawn keeps getting sick despite your best efforts, or if you can’t tell what’s going on, it might be time to call in a pro. At Lawn Thumbs, we specialize in diagnosing and treating lawn disease in Utah. We can help you get your yard back on track with tailored plans, reliable treatments, and honest advice.

We also offer routine lawn care packages that include disease monitoring, fertilization, and aeration, all things that help prevent fungus before it takes hold.

Final Thoughts

Lawn diseases can be frustrating, but they’re not unbeatable. With a little knowledge, regular care, and smart prevention, you can keep your grass healthy year-round. If you’re ever unsure, don’t hesitate to reach out. At Lawn Thumbs, we’re always ready to help Utah homeowners grow their best lawns.

Thanks for reading—and good luck out there!