Brown patch lawn disease is one of the most destructive of all turf lawn diseases. It sneaks up on you and destroys large areas of turf virtually overnight when the weather conditions are just right.

Brown patch lawn disease isn’t picky; it attacks a wide variety of grass types, and really likes the lawns receiving large amounts of fast release nitrogen fertilizer.

Learn more about how lawn disease develops and tips to prevent it.

Brown Patch Loves Hot Summer

“Brown Patch is the most damaging turf grass disease”

Brown patch is really a summer lawn disease that’s caused by a fungus called Rhizoctonia. The disease begins to show growth when temperatures reach 65°, but the most active growth of brown patch lawn disease occurs at temperatures of 80-85° when humidity levels are very high.

The fungi survive the winter in plant debris (thatch) and enter the leaf tissue through wounds caused by mowing and through the pores (or stomata) when daytime temperatures get into the 70s. Infected turf grass can go quite a while without showing damage because it’s actively growing. But, if the daytime temperatures reach the mid 80s and nighttime air temperatures stay above 70°, the grass will be under stress. Then, lawn disease damage can become visible almost immediately.

Once started, brown patch lawn disease spreads fast. Brown patch damage first appears as circular areas of brown and dead grass surrounded by a narrow, dark ring. This dark, smoke ring is not always visible, but is more likely to appear in the early morning when there’s dew on the grass. Brown patch lawn disease grows out from a central point, so these circular areas can enlarge rapidly. Brown patch circles range from a few inches in diameter to several feet, and are not always true circles. Sometimes the patches grow together, creating large irregular dead areas. Diseased turf first appears water soaked with leaf edges showing a wavy or wilted pattern, but soon dies completely and mats down, creating a sunken effect.

Cultural Management: Preventing Brown Patch Lawn Disease

Since high levels of fast release nitrogen increase disease activity, Spring-Green uses a correct blend of fertilizers for lawn fertilizing during the warmer months. Mow less frequently during periods of hot and humid weather, this reduces stress and limits the movement of grass disease by being carried on your feet or mower. If possible, increase light and air penetration, or movement, by pruning overhanging trees and shrubs. During cooler seasons, open up the thatch layer with power core aeration. If these cultural cures fail, a preventative fungicide lawn treatment program may have to be applied to control this most damaging of lawn diseases.


  • Brown patch is the most damaging of all turf grass diseases
  • Brown patch lawn disease becomes most active when day temperatures are over 85° and night air stays above 70°
  • Because infected plants may appear healthy, brown patch damage can occur very fast when conditions are right
  • Avoid high levels of nitrogen in fast release form; it encourages brown patch development

Learn more about grass facts and keeping your lawn healthy and green. At Spring-Green, we take brown patch lawn disease seriously because we know the damage it can cause. If you ever suspect this disease of infecting your turf, please contact your neighborhood Spring-Green lawn service.

Learn more about…

Lawn Patch Ring Diseases

Dollar Spot

Fairy Rings

What Causes Brown Spots On Lawns During The Fall?

Shades of brown are a common sight in the fall season, from the fallen leaves that crunch under our feet to the bare tree branches that hang above our heads.

But brown spots in the grass during fall? They sure do stick out like a sore thumb! Plus, they can cause concern about the health of your lawn.

If you’re wondering what the deal is with the brown patches on your lawn, read on for a potential explanation.

Why Does Grass Turn Brown In Fall?

The short answer is lawns are either turning brown because winter is on its way, or there’s a different issue like a disease or poor maintenance.

Let’s get into more detail to figure out what’s going on with your lawn.

I have brown spots in my grass shaped like circles

Chances are, that’s brown patch disease. Brown patch can appear in lawns in early fall if it’s humid and temperatures are about 70 degrees and up.

Your lawn likely has brown patch if:

  • There are brown patches roughly shaped like circles that are up to several feet wide
  • In the center of the patch, the grass is green, creating a doughnut-like look

There are a few things you can do to relieve your grass of brown patch disease:

  • Only water your lawn if it’s dry. When you do water, plan to do it in the morning
  • Mow your lawn at the proper height (the sweet spot is 2-4 inches) and aerate your lawn if it has lots of thatch—a layer of dead grass that builds up between the soil and live grass
  • Talk to your local arborist about a fungicide to treat brown patch

My entire lawn turned brown in fall

If you live in a warm climate, there’s likely no need to worry. Warm-season grasses like zoysiagrass or bermudagrass turn brown in fall season to prep for winter. As temperatures cool down, warm-season grasses go dormant to protect themselves from winter elements, and then they’re back in action come springtime.

As long as your lawn is pretty evenly brown, and not covered in blotchy brown patches, you don’t need to be concerned.

I have bare brown patches of grass

That could happen for a number of reasons, like low mowing, heavy foot traffic or sunburned spots that are still lingering after summer. Overseeding helps restore lawns with problem areas. Depending on where you live, it might be best to overseed in fall right when you spot an issue. But first, check here to find out the best time to overseed the lawn in your region.

How To Proactively Prevent Brown Patches On Lawns

Staying on top of proper lawn care can really make a difference in the look and health of your lawn. If you want to get ahead of the game and stop brown spots before they start, look to these lawn care essentials:

  • Water a few times a week for a total of one inch of water per week. Always try to avoid over-watering your grass so you don’t create a moist, fungus-friendly environment. A good rule of thumb is to water in the morning so the grass blades can take the day to dry off
  • Mow to keep your lawn at a height of 2-to-4 inches. The best mowing height depends on the season
  • Fertilize the grass to keep it green and in good health. But, be careful not to cause fertilizer burn

The Best Time to Apply Lawn Treatments

The 2-to-3 weeks before winter elements kick in is the best time to treat your lawn with fertilizer. Read all about the benefits of fertilizing your lawn in fall here.

Brown Spots On Lawn & Other Signs of Summer Lawn Stress

Some simple detective work can uncover the culprits behind brown summer lawns. Learn what to look for when lawn brownouts occur and what to do to keep grass healthy.

Drought Stress

Like any plant, grass reacts to summer’s high temperatures and lack of water with wilting, browning, or even death. Here’s how to detect drought stress:

  • Locate a brown patch, and pull on the grass. If it won’t pull easily from soil and is firmly rooted, it’s likely brown due to drought.
  • Push a screwdriver into soil in brown and green lawn areas. If the blade slips easily into green lawn and won’t penetrate brown, soil is dry. In rocky soil, dig a small hole to check soil moisture.
  • Look at the lawn as a whole. When drought is the culprit, brown patches appear randomly and in rough patterns. Lawn near a sprinkler head may be green, while lawn further away is brown. Grassy areas in shade remain greener when parts in full sun turn brown due to drought. Lawn in low spots will remain green while higher areas turn brown.
  • Learn early signs of drought stress. Footprints remain on grass after it’s walked on. Kentucky Bluegrass develops a grayish cast, while other grasses become darker hued. Grass blades may also wilt.


During periods of hot, dry conditions, both cool- and warm-season grasses can go dormant as a protective measure. If grass receives sufficient moisture, growth slows and blades remain green. During times of prolonged drought without irrigation, grass turns brown. If grass turns brown, don’t irrigate it unless you plan to continue watering the rest of the summer. When grass shifts out of dormancy, roots are depleted of food reserves, making plants susceptible to further stresses.

Don’t let newly-established lawns go dormant. With a limited root system, a new lawn might not survive dormancy without extensive injury.

It varies by region, but grass that’s completely dormant may take up to 3-4 weeks, as irrigation is provided, to turn green. Providing more water than a lawn needs doesn’t hasten awakening from dormancy. You also may have to reseed a lawn that has gone dormant, especially with cool-season grasses.


Lawns also turn brown during summer due to insect activity.

  • To determine if root-munching insects are present, pull firmly on brown grass. If it slips from soil and few or no roots are present, White Grubs may be to blame. To learn more about Grub control and how to identify a Grub infestation in your yard, read Dealing with lawn grubs.
  • Other insects eat grass blades, which causes lawn patches to appear as if they have been mowed too closely.

Insects that attack lawns during summer include White Grubs, Chinch Bugs, Sod Webworms, Army Worms, and Cranberry Girdler. Check with your local Cooperative Extension System office to learn which pests plague which grass types in your area, the best methods for insect control, and how to deal with an insect infestation.

Cultural Practices

Fertilizing cool-season grasses during summer, cutting grass too short and overwatering can weaken turf to the point that the grass becomes thin, exposing soil to weed seeds and insects.

A lawn that’s frequently used for parking or does not receive regular aeration is more likely to have compacted soil, which produces poorly-rooted grass that struggles to survive even when moisture is plentiful. Avoid heavy foot and vehicle traffic on lawns during drought.

Lawn Diseases

Summer is also the time when many lawn diseases attack, and lawns that are stressed due to drought are more susceptible to disease organisms. Other conditions that predispose a lawn to disease include consistently watering after dark and mowing with a dull blade that tears grass. The jagged, torn edges create more openings for disease organisms to enter grass blades.

How to Identify and Control Brown Patch

When lawn disease strikes, your dreams of a thick, beautiful lawn may seem to slip out of reach. But the solution to your problems can be as simple as disease I.D. and changes in your lawn care routine. Most common lawn diseases start with fungal pathogens that can’t flourish unless conditions favor their growth. With proper lawn disease identification and disease-fighting culture, you can control disease and enjoy a healthy lawn.

Brown patch disease strikes lawns from late spring through summer months, continuing into fall. All parts of the grass plant — from roots to blade tips — are affected by this disease. Bermudagrass,perennial ryegrass, and tall fescue are common brown patch targets. The disease often attacks fine fescues and Kentucky bluegrass as well.1,2

  • Symptoms and signs: Brown patch may show itself as early as spring green-up, especially in Bermudagrass lawns. Sunken, circular patches of dead, tan grass appear, measuring up to 3 feet in diameter. The patches expand up to 20 feet wide, ringed with smoky, grayish margins of wilted, dark, dying grass.
  • Contributing factors: High humidity combined with hot temperatures during spring and fall favor the development of brown patch disease. Overfertilizing, overwatering, heavy thatch buildup, and mowing too short contribute to the disease.
  • Cultural control: Fight brown patch disease with good water management to avoid overwatering. Water early in the day, so grass dries well by night. Avoid excessive nitrogen fertilizer, and dethatch if your thatch layer is more than 1/2 inch thick. Follow guidelines for proper mowing to avoid mowing too short.

When cultural controls fail to manage fungal lawn diseases, a lawn fungicide can help. As with garden fungicides, early treatment is key to preventing fungal pathogens from germinating and spreading. Many effective fungicides are available only to lawn professionals. Your local county extension agent is an excellent source for information on lawn fungicides and their use for lawn diseases.

For any type of lawn disease, choosing disease-resistant grass varieties plays an important role in disease prevention and control. Superior grass varieties such as purebred Pennington Smart Seedgrasses are backed by decades of industry-leading research and breeding to provide you with the finest in sustainability-enhancing lawn grasses with outstanding disease resistance.

By being proactive and providing your lawn with the care it needs, you can restore balance and enjoy a thick, healthy lawn again. Pennington is here to help with timely, expert lawn advice and premium seed and lawn care products, so you can know the satisfaction of a disease-free lawn you’re proud to call your own.

Pennington with design and Smart Seed are trademarks of Pennington Seed, Inc.


  1. NextGen Turf Research, “Disease Overview: Turfgrass Disease,” April 2016.
  2. Bruneau and Lucas, “Diseases of Warm-Season Grasses,” North Carolina State Extension, August 1995.

Photo credit: William M. Brown Jr., (CC BY 3.0 US)

Solved! What to Do About Lawn Fungus


Q: My lawn was so lush and green last year but this year it’s full of unsightly brown patches that won’t green up no matter how much I water my yard. How can I get rid of the patches and get my beautiful lawn back?

A: It sounds as if you might have a case of the lawn fungus known as “brown patch” on your hands. It’s just one of a number of fungal diseases that can wreak havoc on turf grass. Other types may appear as rings of mushrooms, streaks in the lawn, slimy areas, spots on individual leaf blades, discoloration, or powdery blotches. Keep in mind that your lawn is a living entity, and it naturally contains millions of fungi spores, most of which will never cause problems. Under adverse circumstances, however, such as long rainy seasons, droughts, overwatering, and substandard lawn care, fungi can spread out of control, leaving you with a blighted lawn. The good news is that you can treat many cases of lawn fungus—and prevent future cases—just by following good lawn care practices. And, for particularly stubborn cases, you may find a solution via the application of a topical fungicide.


Water your lawn early in the day. Healthy lawns need approximately an inch of water weekly, but the sooner the grass dries up after watering, the less chance it has of developing lawn fungus. By watering early in the morning, your lawn has the entire day to dry.

Sharpen your mower blades. Dull mower blades tear off the tops of the grass leaves instead of cutting them. Ragged, frayed blades of grass are more susceptible to developing fungal disease than those with sharp, clean cuts. Mower blades should be sharpened in the spring before the mowing season starts. If you have a large lawn, you may want to sharpen your mower blades a second time during the summer.

Remove no more than one-third of the grass height when mowing. Cutting away more of the grass stresses and weakens it, increasing the risk of a fungal disease. Fescue, the most common turf grass, should be mowed approximately 3.5 inches high. Bermuda grass does well if mowed at 2 inches high, and zoysia grass at 2.5 to 3 inches high. Removing no more than one-third of the grass may mean mowing more frequently during times of quick growth, but it will help keep your lawn healthy, and a healthy lawn is a strong deterrent to lawn fungus.

Don’t over- or under-fertilize. If your grass doesn’t have the nutrients it needs, it won’t develop a strong root and leaf system, but if you apply too much fertilizer, you will encourage rapid blade growth that the roots cannot support. Both are mistakes that stress the grass and increase the risk of disease. Choose a fertilizer for your specific type of turf grass (fescue, Bermuda, etc.) and use a fertilizing applicator that you can regulate to dispense the exact amount of product recommended by the fertilizer manufacturer.

Dethatch to remove dead grass. Over time, dead grass can build up at the soil level, choking out healthy grass blades and increasing the risk of lawn fungus. Dethatching is the process of removing the dead grass, which can be done manually by raking it away with a special dethatching rake. It’s a time-consuming process, however, and if your yard is large, you may want to rent a power dethatching rake from a lawn-and-garden center. Dethatching attachments are also available for some types of riding mowers.

Aerate your yard to loosen compacted soil. Compacted soil can result from heavy clay content or from driving over your yard, which can compress the soil. The condensed soil restricts healthy grass development and reduces drainage, both of which can lead to the growth of lawn fungus. The simplest option is to hire a landscape company to aerate your yard, but if you’re DIY-inclined, you can rent a powered aerator from a landscape center and get to work. Aerating removes small plugs of soil, loosening the ground, and increasing circulation around grass roots. Lawns with soil heavy in clay will benefit from annual aeration, while other lawns should be aerated once every two to four years to maintain optimum health.

Check and amend your soil. Most types of turf grass grow the best in well-drained soil with a pH level between 6 and 7. To ensure that your grass has the correct nutrients and pH level, take a soil sample to your local Extension Office. The Cooperative Extension Service (CES) is a branch of the USDA that works in conjunction with state universities to research and advise citizens on the best agricultural practices in their regions. On the CES website, you can locate the Extension Office in your county. They will test your soil sample and give you explicit details about what type of soil amendments are necessary in order to make your lawn healthier. This service usually runs less than $20.

Apply a fungicide. If the preceding steps do not eradicate your lawn fungus problem, you may need to apply a topical fungicide. A broad-spectrum fungicide product will treat many types of fungus, but for the best results, take a sample of the diseased turf grass to an Extension Office, mentioned above, and request that the sample be tested to pinpoint the exact fungus that is causing the problem. You’ll receive detailed information that identifies the fungus and recommends the best type of fungicide for treating it.

How to Tell The Difference Between Dead and Dormant Grass

Brown grass can be a confusing sight to see on your property.

But before you can address this problem, you need to know what’s causing it — and if the grass is still alive.

It’s difficult to tell if your grass is dead or just dormant. Grass that is dead will not come back, but there are steps you can take to have a lush, green lawn again.

On the other hand, dormancy is a natural protection mechanism for grass to withstand weather changes.

So you’re wondering how to tell the difference between dead and dormant grass?

Here are five ways you can tell — and improve your lawn in the process.

Try the Tug Test

You may not be able to see a real difference between dead and dormant grass, but there is a test you can perform to get an answer.

Find a section of brown grass, grab some in your hand and pull. If the grass comes out easily with no resistance, it is dead.

Dead grass isn’t coming back, so you’ll need to take steps to regrow your lawn. You can replace the grass by seeding or sodding — or installing a new type of landscaping material such as mulch, rocks or groundcover.

To seed your lawn, first mow the grass (collecting the clippings) shorter than normal so the seeds can better reach the ground. You should also add soil amendments to give the seeds a healthy environment to grow before spreading the seeds.

Laying sod can be a strenuous task. You’ll need to first remove the dead grass and prep the soil before laying the new sod.

Whether you seed or sod, you’ll need to continue to water and feed the lawn after installation to ensure healthy growth.

Look for Patterns

Is your entire lawn brown, or are there distinct patches of brown grass?

When your whole lawn is the same brown color, the grass may be dormant. However, if there are areas or circles of brown grass, that can point to these spots being dead.

Before you count this grass out, you’ll need to rule out possible pests and disease that can cause similar symptoms. Work with a professional to have the area and soil tested to find the cause of the brown turf.

Consider Temperature Changes

The temperature and weather conditions will greatly affect your lawn’s appearance.

Cool-season grasses will go dormant during prolonged heat periods, while warm-season grasses will go dormant during the winter. The grass is still alive and will become green again when the correct temperature returns.

If you want your grass to remain green year round regardless of the temperature, you can plant a mixture of cool- and warm-season grasses.

Follow Watering Schedule

Excessive heat and dry conditions can also cause the grass to become dormant, but that can lead to the grass dying if the proper steps aren’t taken. That can make it difficult to know if the grass is still alive.

You can get a better idea of what’s causing the brown color by following a consistent watering schedule. Watering will help dormant grass become green again, while dead grass will remain brown.

Turn to a Professional for Help with Your Lawn

It can be hard to decipher between dead and dormant grass — and even more difficult to know what you should do to treat the problem.

Hiring a lawn care company can help you figure out what’s going on with your lawn and how to best treat it.

In 2018, Michael Hatcher & Associates, Inc. acquired a Memphis-based lawn care company, Master Lawn.

This new brand name and focused division of our organization treats plants, trees and turf for unwanted pests, which can include spray services for ants and ticks, diseases and weeds throughout Memphis and the Mid-South.

Revive Dead or Dormant Grass with These Easy Steps

By Marty Ross

When heat and drought set in, lawns may turn brown and appear lifeless. However, they may not be dead, but conserving resources until conditions improve. For both cool and warm climate lawns, seasonal dormancy is normal.

The best way to make sure your lawn bounces back from a period of dormancy is to continuously take care of it. A lawn that is well-watered, free of weeds, and mowed properly will experience less dormancy with faster recovery times.

How to Revive Brown Grass

  • Water
  • Naturally, rain will revive a brown lawn. However, if rainfall is insufficient watering the lawn deeply once a week will help your lawn to spring back to green. With Gilmour’s Pattern Master Circular sprinkler, you can customize the spray area so you water only the lawn and not the sidewalk. Set up a timer on your spigot, so the sprinkler will come on for 15-20 minutes per watering session. The best time to water is early in the morning between 6 a.m. and 10 a.m., when it’s usually less windy and when temperatures are low.

  • Mow
  • Once grass starts to grow again, it’s okay to mow with your mower set to 3 ½ inches. Do not scalp the lawn to try to remove brown blades of grass. Let new fresh grass grow around them. Leave grass clippings on the lawn to fertilize the lawn naturally.

  • Weed
  • When soil is rehydrated and grass plants turn green, so will the weeds. Remove them by hand or spot-treat with a natural herbicide by following directions on the label.

Dormant Lawn FAQs

How can I tell if my grass is dormant (brown) or dead?

One way to determine if grass is dormant or dead is by tugging on the grass plants. If the plants pull out from the ground easily, they’re probably dead. If the roots hold fast when pulled, the plants are dormant. You will also see the difference when you start to water or when rain returns as moisture will revive brown grass. However, it will not bring dead grass plants back to life.

Why is my grass turning brown?

Grass turns brown in response to stress. Heat and drought put a lot of stress on grass during the summer. Even warm climate grasses may turn brown for a few weeks.

How long can a lawn go without water?

A healthy lawn can survive up to four weeks without water. If a drought persists, water with a Gilmour Flexogen Super Duty hose and Adjustable Wind-resistant Rectangular Sprinkler by following these tips.

What can I do to help my lawn before dormant periods?

Lawns should be watered deeply but infrequently, about once a week, for 20-30 minutes. Watering before summer dormancy will encourage grass plants to develop deep roots, giving them better access to moisture in the soil.

How can I protect my lawn when the grass turns brown?

You can take care of a brown lawn by limiting further stress on grass plants. Mow less often, or not at all, during a drought. If you do mow, set the mower height higher than normal at about 3 ½ inches. Tall blades of grass shade the soil, which reduces evaporation and retains moisture. When grass is dormant or beginning to grow again, it’s best not to walk on it.

What about fertilizing?

Do not fertilize a brown lawn. You do not want to promote leaf growth at a time when the roots have little access to moisture.

What about weeds? Are they dormant, too?

Some weeds may grow while the grass is dormant. Dandelions, for example, are perennial weeds with tap roots that reach into the soil for moisture. They can survive heat and drought. The best way to keep weeds in check is to maintain a healthy lawn. If you see weeds actively growing when your lawn is dormant, pull them by hand or spot-treat with an organic herbicide (follow directions on the label).

If hot weather and drought make your grass turn brown, just remember that brown lawns are not necessarily dead lawns. Good lawn care practices and a little patience are all you need.

Getty Images

My lawn was wrecked by last summer’s drought. I was going to renew it last fall, but then I got busy at work. Can I do it this spring, or should I wait until next fall and overhaul it then?

Go for it. Sure, it’s true that late summer and early fall are the ideal times to rejuvenate a patchy or threadbare lawn. Soil temperatures are high, which leads to quick germination of grass seeds, especially tall fescue. The new grass then gets a jump on weeds the following spring, crowding them out before they have a chance to gain a foothold. But even though you missed your chance last year, that doesn’t mean you have to put up with a lousy-looking lawn all summer.

First, determine how severe the damage is. It’s worth noting that a brown lawn isn’t always a dead lawn. Some turfgrasses, such as Kentucky bluegrass, go dormant during a drought. If that’s the case, and its root structure is sound, it will green up following a few spring showers. But until then, look among the brown, straw-like grass for any surviving green shoots that signal there’s life in your old lawn yet. If you’re resigned to the fact that less than half the lawn is salvageable, try to make it as presentable as you can through the summer, and then start over in the fall. The most effective way to reseed is to use a slit seeder. These resemble push mowers and feature circular blades that slice the soil before depositing seed directly into it. Work over the lawn in two passes, making the second application diagonally at 45 degrees over the first.

If half or more of the lawn looks decent, chances are good you can whip it back into shapebut get an early start. Use a rake to remove dead grass and roughen the soil, then apply new seed with a drop or rotary spreader. Be sure to press the seed into the dirt with either a lawn roller or gentle, evenly spaced footsteps. Also, try to keep the area moist, and fertilize it with a high-phosphorus seed-starting fertilizer.

Remember to fertilize responsibly. Sweep or blow excess fertilizer from paved surfaces back onto the lawn and thoroughly water it immediately after applyingbut don’t overwater and create runoff. Watering the fertilizer into the ground starts the feeding process, and it prevents loose fertilizer from washing into lakes and streams, where it promotes algal blooms that suffocate fish and other species.

For the rest of the summer, follow typical healthy-lawn practices: Raise the mower up to the highest setting, mow with a sharp blade, mulch whenever possible to return nitrogen-rich grass clippings back to the lawn, and provide about 1 inch of water per week to the lawn.

Lawn disease requires the right combination of grass type, environment and pathogen. The detail above shows the grayish-white mycelium of gray snow mold covering a section of turf. The damage to your lawn can be extensive. (Photograph by Alan and Linda Detrick)
Fairy rings form in soil that’s high in woody organic matter. In moist conditions, the rings may be accompanied by mushrooms. (Photograph by Dr. Peter Landschoot) >
Cool-weather stripe smut displays black stripes of erupted spores on blades. Grass becomes dry and blades curl. (Photograph by American Phytopathological Society)
(Photograph by Alan and Linda Detrick) >
Brown patch features circular areas ranging from a few inches to several feet in diameter. Healthy green leaves may persist in brown areas. (Photograph by Dr. Peter Landschoot)
Pink snow mold develops from late fall to early spring, during moist cool weather, with or without snow cover. Pink mycelium is visible in sunlight. (Photograph by Dr. Peter Landschoot) >
Dollar spot affects low-nitrogen lawns–especially when the grass is stressed by drought and subject to heavy dew. (Photograph by American Phytopathological Society)
Rust appears on low-fertility, compacted or shady lawns, when growth slows due to hot, dry weather. (Photograph by American Phytopathological Society)

Lawn Diseases

Many different diseases can affect lawns in Florida, including rust, brown patch, take-all root rot, and several different types of leaf spots. Keep an eye on the overall quality of your lawn. If discolored areas appear, this may be a sign of disease.

However, brown or yellow areas can also be caused by other factors like drought or cold damage. Don’t apply any chemicals unless you know what’s really going on.

Large patch is a fungal disease that can affect zoysiagrass and St. Augustinegrass lawns. It shows up as round, discolored patches that expand over time. The borders of the patches are sometimes orange, and the centers appear brown and sunken. It’s also known as brown patch or rhizoctonia blight.

This disease often becomes a problem in spring, when cooler temperatures and damp weather create ideal conditions for the fungus. In summer the surrounding lawn may grow, filling in the dead patches, but if the disease isn’t controlled, the problem will return again in fall.

The best way to prevent large patch is to care for your lawn properly, since incorrect watering, mowing, or fertilizing practices all make your grass more susceptible to disease.

With recent summers full of rain, Florida homeowners need to be on the lookout for take-all root rot. This fungus naturally occurs on the roots of turf year-round in many lawns, but only becomes a problem with prolonged periods of rain or when a lawn is stressed.

The initial symptoms appear on the roots, but you’re unlikely to notice them. If the turf is not being correctly watered, fertilized, or mowed, symptoms will begin to show above-ground as irregular yellow or light-green patches. Then the grass will begin to thin and die. By this time, the damage is done, so your best bet is prevention—avoid overwatering and fertilizing too much or too often.

You can take a sample of grass from the affected area to your local Extension office for identification.

And remember that one of the best ways to prevent disease is to maintain your lawn properly. Follow the UF/IFAS recommendations for mowing, watering, and fertilizing to help ensure you have a strong, healthy, Florida-Friendly lawn.


  • Rapid Turfgrass Diagnostic Service

UF/IFAS Publications

  • Brown Patch
  • Homeowner’s Guide to Fungicides for Lawn and Landscape Disease Management
  • Florida Lawn Handbook: Disease Problems
  • Take-All Root Rot
  • Turfgrass Disease Management

Also on Gardening Solutions

  • How to Take a Turfgrass Sample

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