Leaf spot Fungal Disease

Leaf Spot usually starts as small brown, black, purple, or tan spots on individual grass blades. The spots may have darker borders and lighter centers, giving the leaf blade a speckled or damaged appearance.

As the disease worsens, infected grass blades may turn yellow, brown, or straw-colored. In more severe cases, the disease can move from the leaf blades into the crown and roots, causing thinning or larger damaged areas. This more advanced stage is often called “melting out.”

Leaf Spot develops when fungal pathogens infect stressed grass during wet, humid, or high-stress conditions. It is often worse when lawns are mowed too low, watered too often, growing in shade, compacted, or stressed by heat, drought, or poor fertility.

The disease can spread through mowing, splashing water, infected clippings, foot traffic, and equipment. Lawns with poor airflow or extended leaf wetness are more likely to develop noticeable Leaf Spot symptoms.

Prevent Leaf Spot by reducing lawn stress and keeping the grass healthy. Mow at the proper height for your lawn type, avoid scalping, use a sharp mower blade, and avoid mowing when the grass is wet.

Water deeply and early in the morning instead of frequent light watering. Improve airflow in shaded or tight areas, correct compaction when needed, and follow a balanced fertilizer program without overapplying quick-release nitrogen during disease-prone weather.

Use a lawn fungicide labeled for Leaf Spot and safe for your specific grass type if the disease is active, spreading, or causing thinning. Apply according to the product label and rotate fungicide groups if repeat applications are needed.

For mild cases, improving mowing height, watering habits, airflow, and turf health may be enough to help the lawn recover. If the disease has progressed into melting out, recovery may take longer and thin areas may need overseeding during the proper season.