Large Patch and Spring Dead Spot Symptoms Showing Now

Large Patch

We are getting reports of Large Patch and Spring Dead Spot showing in lawns throughout the South and Southeast regions. These diseases were formerly called Brown Patch, a disease that affects cool-season grasses in the middle of the summer.

These diseases begin to infect turf in the fall and the symptoms show in the late spring to early summer as the lawns come out of winter dormancy. Brown Patch on cool-season grasses begins to infect the turf during periods of high heat and humidity and the symptoms immediately show on the lawn.

Large Patch Symptoms and Grasses Commonly Affected

Large Patch is mainly a disease of Centipede, Zoysia and St, Augustine lawns. Spring Dead Spot affects Bermuda grass. The infection begins to develop when soil temperatures drop to about 70 degrees in the fall. The symptoms may show in the fall, but more likely they will show during the spring of the following year, especially during cool, wet periods. The symptoms are very noticeable as these grasses start greening up.

Large patch is more likely to show up on lawns that receive excessive nitrogen fertilization in the fall and spring, have excessive thatch layers, have been overwatered or been mowed too low. Centipede grass is most susceptible to the disease, followed by Zoysia, St Augustine and Bermuda grass. Bermuda grass is rarely affected by the disease and will quickly recover if it does get the disease.

Spring Dead Spot can take 3 to 5 years to become established in a new Bermuda grass lawn. If left untreated, the disease will become more severe each year. The disease attacks all parts of the plant, but does not kill it directly, but allows the plant to become more susceptible to freeze injury during the winter.

Prevention and Treatment

Following good cultural practices of proper mowing, deep and infrequent watering, proper lawn fertilization and annual core aeration will help prevent the disease from occurring. Avoid fertilizing the lawn after the middle of September and don’t fertilize until the grasses begin greening up in the spring.

There are fungicides that work very well on these diseases, but require two applications in the fall, 30 days apart, when soil temperatures drop to below 70 degrees. If you think that your lawn may have Large Patch or Spring Dead Spot, contact your local Spring-Green office to have your lawn checked. They can help develop a program that will benefit your lawn and help to prevent the re-occurrence of Large Patch.

If you have any questions, contact your local neighborhood lawn care professional at Spring-Green.

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.

Is it Too Late to Apply Nitrogen Fertilizer to Warm Season Grasses?

 

nitrogen fertilizer

The simple answer if you are reading this in late August or early September is “No.”  This decision is based on several different factors.  A general rule is to apply the last nitrogen fertilizer to a lawn that contains warm-season turfgrasses two months before the first frost. Unless you live in the deep south, the last application of a fertilizer that contains a high amount of nitrogen would be September 15 at the latest. If you live in the more northern areas, you run the risk of turf damage and lawn disease development if nitrogen is applied after September 1st.  Of course, these are based on averages, so there is a little “wiggle” room, but not much.

 

Applying Nitrogen Fertilizer to Warm Season Grasses

Centipede, St. Augustine, Hybrid Bermuda and Zoysia grass are the most common warm season grasses and they usually go dormant in the late fall.  Applying a high rate of nitrogen after the middle of September for the more moderate warm-season areas will increase the shoot and leaf growth while the plant is slowing its growth.

It is important that these grasses have a chance of “harden-off” before going dormant.  If pushed to grow, the tender new growth is more susceptible to freeze damage.  These succulent shoots are prone to being attacked by a common cool-season disease called Large Patch.

Another problem with fertilizing later in the fall is that it may increase the number of cool-season weeds that germinate. Weeds like henbit, common chickweed and Shepherd’s Purse are considered winter annuals and will grow and spread while the desired grasses have slowed down growing.

Determining Nitrogen, Phosphorus and Potassium in Fertilizer

The three numbers on a bag of fertilizer indicate the percentage by weight of nitrogen, phosphorus and potassium in the bag. The number one nutrient needed by turf is nitrogen. Here is a chart that provides the amount of nitrogen each turf type needs for the entire growing season.

Warm Season Grass#’s of Nitrogen Per Year
Hybrid Bermuda5 to 6 lbs.
Common Bermuda4 to 5 lbs.
Centipede Bermuda1 to 2 lbs.
St. Augustine grass (sun)3 to 4 lbs.
St. Augustine grass (shade)1 to 2 lbs.
Zoysia grass3 to 4 lbs.

 

If you haven’t applied the recommended amount of nitrogen to your lawn this year, don’t try to catch up now.  In regards to the other two nutrients, phosphorus and potassium, they are required, but they are usually found in an abundant amount in the soil. The only way to tell if the lawn needs either of these two nutrients is to have your soil tested.  Most cooperative extension services offer this service at a low fee of less than $25.00 per sample.

If you live within the area that has a first frost date of mid-October, try to fertilize between Labor Day and the end of September, depending whether you are in the northern or southern parts of that zone. If you are not sure, contact your neighborhood lawn care professional at Spring-Green.