Inspecting your new sod while playing outside with your children helps catch potential turf problems without devoting extra time in the day just to examine the sod. Finding discolored patches is a sure sign that brown patch has infected your turf. On established lawns, brown patch typically thins and weakens the turf while new sod that isn’t established can succumb to the fungal disease and die. Knowing what to look for and how to control it will help ensure your new sod is safe from brown patch.
1. Brown Patch Information
Brown patch is a fungal disease caused by Rhizoctonia solani, a strain of fungal pathogen that attacks cool-season turfgrass such as fescues (Festuca spp.), thriving in U.S. Department of Agriculture plant hardiness zones 3 through 6; bentgrasses (Agrostis spp.), growing in USDA zones 4 through 8; and Kentucky bluegrass (Poa pratensis), which is hardy in USDA zones 3 through 8. This disease typically infects turf during long periods of warm weather when nighttime temperatures are above 60 degrees Fahrenheit and high levels of humidity. Turfgrass that remains wet for an extended period of time becomes susceptible to brown patch disease.
2. Signs and Symptoms of Brown Patch
The first signs of brown patch are spots or patches of varying sizes that initially appear purplish green, but will begin to turn brown as this fungal disease progresses. The patches on closely mowed lawns often develop a smoky or purple-colored edge that appears in the morning. If you look closely at the grass blades, you may notice irregular tan spots edged in dark brown on the leaves.
3. Cultural Control of Brown Patch
Cultural and environmental conditions play a vital role in the brown patch development. A lawn well maintained and properly cared for is less likely to develop brown patch. Proper mowing height, irrigation, soil drainage and fertilizing will help control fungal disease of turfgrass. High levels of nitrogen caused by over-fertilization create lush growth, and soils with poor drainage leads to soggy areas. These conditions create a favorable environment for brown patch. Dethatching the lawn yearly with a dethatching rake removes a buildup of decaying or dead organic debris that collects on the grass blades and helps prevent brown patch.
4. Chemical Control of Brown Patch
Fungicides containing propiconazole applied immediately after the first signs of brown patch appear can help control the fungal disease. This fungicide is available in granular form, which you must apply with a broadcast or drop-type spreader using 3.5 pounds of the granules for every 1,000 square feet treated. The spreader setting will vary depending on the type of spreader you have. For example, the drop-type spreader may require a setting of 9.5 while the broadcast spreader needs a 5 setting. For complete control, you must repeat the treatment at 14-day intervals until the brown patch is no longer a problem. Once the disease is under control, repeat the treatment about once a month until the hot, wet weather subsides. This helps prevent brown patch from reoccurring. Keep in mind that fungicides containing propiconazole are harmful if inhaled, swallowed or absorbed through the skin. Avoid allowing children or pets in the area until the treated area has been watered and allowed to dry.
- UC IPM Online: Rhizoctonia Blight (Brown Patch, Large Patch, Yellow Patch)
- Clemson Cooperative Extension: Brown Patch & Large Patch Diseases of Lawns
- Bayer Advanced: Fungus Control for Lawns
- Clemson University Cooperative Extension Service: Brown Patch & Large Patch Diseases of Lawns
- Missouri Botanical Garden: Festuca Arundinacea (Mix)
- OnlinePlantGuide.com: Agrostis Palustris / Bentgrass
- OnlinePlantGuide.com: Poa Pratensis / Kentucky Bluegrass
- Missouri Botanical Garden: Festuca Rubra "Pennlawn"
- Dynamic Graphics Group/Dynamic Graphics Group/Getty Images