A lush green lawn enhances the curb appeal of your home while creating a welcoming outdoor space for family recreation. However, fungal diseases like leaf blight can quickly leave healthy grass looking like a brown, patchy mess. Its rapid spread in warm, humid conditions means leaf blight has the potential to weaken your turf and make it easier to damage. Understanding what this fungal disease looks like helps you spot it when you see it. Noticing the symptoms and knowing the causes makes it simple to treat and prevent leaf blight and better maintain a thriving lawn.

What Is Leaf Blight?

Leaf blight affects plant leaves, including grass, causing yellowing, wilting and premature death. Mostly fungal but sometimes bacterial, this condition thrives in warm, humid settings and quickly spreads if you don’t treat it quickly. While leaf blight impacts many plants, this disease can destroy lawns because it weakens the turf and leaves your yard more vulnerable to other diseases and environmental stress.

What Does Leaf Blight Look Like?

Grass blades with irregular brown or tan lesions may have a type of leaf blight called northern corn leaf blight. This discoloration often includes a yellow or reddish halo surrounding the damaged area. 

Leaves infected with ascochyta leaf blight may turn the color of yellow straw and shrivel, developing a scorched appearance. Plants with cucumber leaf blight usually have dark brown spots with yellow halos, while leaf blight lilac diseases feature irregular dark brown spots that enlarge and come together to cause leaf death. No matter the variety, this disease can turn large patches of vibrant green grass into a brown and ugly hue. It can also thin out the blades, leaving your lawn looking patchy and unhealthy.

Symptoms of Leaf Blight

This lawn disease has a distinctive appearance you can easily spot once you know what to look for, helping you out when you want to know how to fix leaf blight. If you notice the following symptoms, your lawn probably has a problem with leaf blight.

• Small water-soaked spots that get bigger and turn brown
• Grass blades that curl up and turn yellow
• Thinning turf and patchy spots of dead grass
• Affected areas that spread quickly during warm, wet weather

Commonly Confused Conditions

Though leaf blight has a unique look, it can be mistaken for drought stress, grub damage or nutrient deficiencies. By contrast, leaf blight presents irregular patches and distinct lesions on individual grass blades. Other fungal infections like dollar spot or brown patch may resemble it, but both typically have more circular, defined patterns.

What Causes Leaf Blight in Grass?

Fungal pathogens typically cause leaf blight, including varieties such as Drechslera, Bipolaris and Curvularia. These fungi thrive in warm, moist conditions, and several factors contribute to their development:

• Excess moisture: Setting your sprinklers to water too long, heavy dew and frequent rainfall prolong wetness on your lawn, creating the ideal conditions for fungal growth.
• Poor air circulation: Thick, dense grass often retains moisture, allowing fungal spores to spread.
• Nutrient imbalances: Excess nitrogen may encourage lush growth, but it also makes grass more susceptible to leaf blight.
• Compacted soil: Poor drainage and compacted soil prevent roots from developing properly, weakening grass and increasing its vulnerability to leaf blight.

Most Common Plants or Grass Types Impacted

Certain grass types are more prone to leaf blight, including:

• Kentucky bluegrass: Found in the Northern and transition zones, this cool-season grass often gets leaf blight during humid summers.
• Tall fescue: Common in the Midwest and Mid-Atlantic regions, this durable turf grass sometimes develops leaf blight when overfertilized.
• Perennial ryegrass: Popular in the Northwest and Pacific Northwest, this fine-bladed grass struggles with fungal diseases during damp conditions.
• Bermuda grass: Widely used in the South, this grass typically suffers from leaf blight when poorly managed.

How to Treat Leaf Blight

Addressing the problem early helps prevent widespread damage. Some effective ways to treat the damage this plant disease causes include: 

• Reducing moisture: Water early in the morning so grass dries quickly, avoid overwatering your lawn and improve drainage so water penetrates the ground better.
• Mowing properly: Keep your grass at the recommended height for its species. Don’t mow your lawn when it’s wet because doing so can spread fungal spores.
• Applying fungicides: Use a fungicide labeled for leaf blight to stop the progression of this common lawn disease.
• Aerating and dethatching: Improve your lawn’s airflow and reduce moisture retention by aerating compacted soil and removing excess thatch.
• Adjusting fertilization: Avoid applying excess nitrogen. Rapid growth makes your grass more vulnerable to leaf blight infections.

How to Prevent Leaf Blight

Preventative lawn care reduces the risk of leaf blight and promotes a healthier lawn. Follow these best practices to keep your yard looking its best:

• Water wisely: Deep, infrequent watering that amounts to 1-1.5 inches per week encourages strong root growth and reduces surface moisture.
• Mow correctly: Keep your mower blades sharp and cut no more than one-third of the grass blade height at a time to keep your lawn healthy.
• Improve soil conditions: Aerate your soil annually to prevent soil compaction. This practice also helps your lawn drain better after excessive rainfall.
• Apply preventative fungicides: Look for high-risk areas of your lawn and apply fungicide before symptoms of leaf blight appear.
• Promote air circulation: Decrease moisture buildup by trimming overhanging trees and shrubs to reduce shade and increase airflow to your lawn.

Leaf blight can severely damage your lawn if you don’t manage the disease properly. Recognizing early signs and taking proactive steps to improve the health of your yard can prevent and control the disease, ensuring optimal outcomes. 

For expert lawn care solutions, contact Lawn Doctor today. Our experienced professionals provide tailored treatments for leaf blight and other conditions, keeping your lawn green, healthy and free from disease.