Diagnosing and Managing Brown Patches on Your Lawn

Turfgrass Damage

The beauty and green color of your lawn can be affected by many things, from heat and drought to weeds, invasive grasses, insects and diseases. Troublesome and unsightly brown patches often occur in the blink of an eye. You water more and more, yet the brown patches continue to grow. So, what is the trouble with your turf, and how do you address it? The first step is to diagnose the problem.

Here are the classic culprits for brown patches on your lawn in the Washington, DC area:

  • Rhizoctonia, better known as Brown Patch Disease
  • Other fungal culprits: Red Thread Disease, Dollar Spot Disease, Leaf Spot Disease
  • Insect damage

Brown Patch Disease

Lack of water is not your problem! Fostered by high temperatures, humidity, and wet soil, Rhizoctonia—a fungal disease— exists in almost all soils and is a key culprit that affects the most dominant grasses in our region (the Transition Zone): tall fescue and fine fescue grasses. Brown patch disease occurs anytime during summer heat waves when the weather is hot and humid. Typically when nighttime temperatures stay above 70ºF and the humidity level is elevated above 50%, Rhizoctonia thrives. That is when the mycelium branch out from the soil or thatch and infect the grass plants which make up your lawn and brown patch disease develops.

While it seldom destroys a lawn, it can cause a thinning of the turf canopy, helping weeds to invade.

Other Fungal Culprits

Other fungal culprits include Red Thread Disease, Dollar Spot Disease, and Leaf Spot Disease.

Red Thread/Pink Patch are common in late spring. They are easily spotted by the reddish gelatinous fungal growth that appears on leaf blades and sheaths. Dollar Spot disease can affect many species of turf grass but is uncommon in tall fescue lawns. It begins as small “silver dollar” size spots which can coalesce into larger areas. Dollar Spot is most common in lawns that have poor nutrition due to poor fertilization practices. Leaf Spot disease first infects grasses in early spring and develops into small brown spots on leaves and stems and quickly enlarges and spreads into larger areas that “melt out.” It thrives in areas with excessive nitrogen levels and is stressed by extended periods of drought, heat and humidity.

Insect Damage

Insects can also cause damage and brown spots in lawns. Sod webworms, cutworms, armyworms, chinch bugs, billbugs, and grubs are all potential culprits. Root feeding insects, such as grubs, do their damage below ground by feeding on the roots of plants, causing wilting and other drought-like damage, consequently making your green grass turn brown; this typically happens in late summer and early fall. Blade feeders, such as sod webworms and chinch bugs, do their damage above ground by consuming blades of grass. Chinch bugs cause wilting and death of grass plants by feeding on their juices while injecting a poison that kills the grass, typically on fine fescue, bluegrass and Zoysia grass in full sun.

Call in the experts

The key to managing brown patches is using proper fertilization and knowing which brown patches are temporary and which are serious threats to your lawn’s health. Before beginning any treatment, it is imperative to diagnose the cause of the brown patches on your lawn. It can be quite tricky getting to the root of the problem, so calling in the experts is highly recommended.

Complete Lawn Care can help you determine exactly what ails your lawn and keep it colorful and vibrant during the summer, and year round. Contact us today for a free analysis and estimate!