Large Patch & Take-All Root Rot: Warm Season Grasses Patch Lawn Diseases

Summertime is for baseball games, playing in the park, taking bike rides and enjoying picnics with friends and families. It’s also the time for patch lawn diseases to become more noticeable in yards.

The patch diseases that can affect warm season grasses such as Bermuda, St. Augustine, Centipede and Zoysia, and affect much of the South and South East lawns include: Large Patch and Take-all Root Rot. These lawn diseases are present in the United States where weather is hot and humid. Although it may be too late to prevent these lawn diseases, there is still time to help your lawn recover from the effect of Large Patch and Take-all Root Rot.

Large Patch Lawn Disease

The prime conditions for Large Patch to occur on warm season grasses include: Zoysia, Centipede, St. Augustine, and Bermuda when the weather turns cool and wet in late summer and into fall. Large Patch, also sometimes referred to as Brown Patch, is active from the late summer through the following spring when grasses are growing slow and preparing to go dormant for the winter. The symptoms go unnoticed until the following spring when lawns start coming out of dormancy.

Large Patch disease favors soil temperatures of about 70˚ and during extended periods of overcast and rain. At first, the grass blades will turn reddish-brown and large patches will begin to develop that turn a yellow-brown color. When the disease is most active, the outer edge of the patch may have a noticeable red or orange color.

Large Patch in Alabama
Damage by Large Patch can last a long time. Infection occurs when the turf is growing slowly, such as when it is going into dormancy in the fall, during cooler temperatures during the winter or during spring green up. Large Patch is not active when temperatures exceed 86°F. Often turf will recover during the summer, but the recovery time can take several weeks. This is a disease that can be controlled with properly timed applications of a fungicide labelled to control Large Patch. Two applications in the fall and one application in the spring can offer effective large patch control.

Take-All Root Rot Lawn Disease

Take-all Root Rot will often cause root decline in most warm-season turfgrasses. In the past, this disease had several names; Bermuda grass decline, Centipede grass decline and St. Augustine grass decline. It is the number one disease that affects St. Augustine grass. Like Large Patch, it is more common in wet areas with either sandy soils or hard, compacted soils.

The patches take on either an irregular or regular circular shape. Symptoms start as grass blades tuning light green to yellow. Stolons often turn black and begin to rot. These symptoms can be confused with other problems, such as plant parasitic nematodes. If the disease is not controlled or if corrective cultural practices are not put into play, the blighted areas will remain and other unwanted grassy weeds or broadleaf weeds will move into the areas.

Treatment for Warm Season Grass Lawn Diseases

Both diseases can be helped with 2 disease control applications, spaced a month apart, applied in the fall when soil temperatures drop below 65°F. Following good cultural practices, including a core aeration in the summer, will help the turf to recover. If you suspect your lawn has one of these patch diseases, contact your neighborhood lawn care professional at Spring-Green.