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Identifying Common Lawn Diseases

Identifying Common Lawn Diseases Header Image

So, you think your lawn has a disease outbreak. Researching what may have potentially caused damage to your lawn is smart on your end.

Not only is it a great idea to take preventative steps to keep disease outbreaks from happening, it’ll also greatly benefit you to learn and use a few identification strategies. If you have a better idea of what to look for in your lawn, you’ll be quicker to act and more likely to treat issues with the appropriate solutions.

It’s always a good idea to learn as much as possible about a topic before spending money on something you don’t understand. Your lawn is a living organism, so certain mistakes can cause consequences that may kill or severely damage it.

To keep this from happening, we dive into some of the most common lawn diseases. Although turfgrass diseases can be hard to accurately identify, the below information can help you get a better idea of what might be going on. The best way to accurately identify your lawn’s issue is by submitting a sample to your local extension office or agency.

Regardless, it’s good to know the basics about lawn diseases. Most lawn diseases are caused by a form of fungus. The fungi need to obtain energy as a means of feeding off of either dead organic matter (and convert the nutrients in dead organisms into energy) or find and take over a host plant.

Some common locations you will find fungi in your lawn will be under dead leaves, the shade or in excessive thatch.

Fungi spread through spores, which are easily transferred through wind, rain, mowing and simply walking through a fungi outbreak.

For fungus to spread and be present, there needs to be three main factors, also known as the disease triangle:
a) a host, living or dead organic matter (thatch and leaves),
b) the right environmental conditions, such as shaded, moist areas to grow in,
c) and the pathogen.

All three must be present for the fungus to grow and spread. Learn more about the disease triangle and what a fungus is here.

Now, let’s take a look at some of the most common lawn diseases. Be sure to refer to our grass-specific care guides for overall best maintenance practices for your grass type.


Anthracnose
Photo Credit: https://nuturf.com.au/problem/anthracnose/

Pathogen: Colletotrichum graminicola/Colletotrichum cereale

Appearance/Symptoms:

  • Reddish-brown to brown spots surrounded by a yellow halo,
  • Over time, these spots expand and cause yellowing and death of the grass blade,
  • Once this has affected several blades, it will cause yellow spots throughout the lawn,
  • Small, black, cushion-like structures with black spines extending from the cushion,
  • Affected areas may spread by mowing.

Affected Grasses:

  • Mostly centipede grass but can affect any warm season grass. It can also affect annual bluegrass and bentgrass.

Time of Year:

  • During the spring where there are warm temperatures and moisture.

Recommended Cultural Treatment/Prevention:

  • Fertilizer without excessive amounts of nitrogen; consider a slow-release nitrogen fertilizer instead,
  • Fertilizer with equal amounts of potassium and nitrogen,
  • Early morning irrigation without excessive watering. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Aerate if you have compact soils,
  • Dethatching,
  • Remove dead leaves and litter from the lawn and garden,
  • Use a balanced fertilizer program like Lawnifi®.

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, chlorothalonil, fenarimol, fludioxonil, metconazole, myclobutanil, propiconazole, thiophanate methyl, triadimefon, trifloxystrobin or triticonazole.

Read product labels thoroughly before application.

Bipolaris Leaf Spot (Helminthosporium Leaf Spot)
Photo Credit: https://www.canr.msu.edu/ipm/diseases/leaf-spot

Pathogen: Bipolaris, Drechslera and Exserohilum spp. (previously classified as Helminthosporium fungi)

Appearance/Symptoms:

  • Spots that range from tiny to expanded lesions,
  • Brown or purple leaf blades,
  • Purple shade of color on the lawn once it expands,
  • Some areas may turn black,
  • No distinct patterns or patches.

Affected Grasses:

  • Can affect all warm season turfgrass but mostly affect bermuda grass.

Time of Year:

  • Due to the fact that this disease is caused by different species that thrive in different temperatures, bipolaris leaf spot can occur any time of the year but usually shows up during wet periods around the fall or winter.

Recommended Cultural Treatment/Prevention:

  • Reduce shade,
  • Aerate,
  • Find a balanced fertilizer program like Lawnifi,
  • Fertilizer without excessive amounts of nitrogen; consider a slow-release nitrogen fertilizer instead,
  • Fertilizer with equal amounts of potassium and nitrogen,
  • Mow at a higher mowing height,
  • Remove dead leaves and litter from the lawn and garden.

Recommended Chemical Treatment/Prevention:

  • Fungicides with chlorothalonil, fludioxonil, iprodione, mancozeb, myclobutanil, propiconazole, pyraclostrobin, trifloxystrobin, triticonazole or vinclozolin.

Read product labels thoroughly before application.

Brown Patch

Pathogen: Rhizoctonia, mostly Rhizoctonia solani but sometimes Rhizoctonia zeae

Appearance/Symptoms:

  • Large patches of dead grass,
  • Thin, circular patches of brown grass,
  • Brown, tan or yellow in color.

Affected Grasses:

  • Most common in tall fescue located in the southeast where temperatures are warmer,
  • Ryegrass,
  • Bentgrass,
  • Bluegrass.

TIme of Year

  • Mid to late summer when temperatures are hot and humid.

Recommended Cultural Treatment/Prevention:

  • Aerate,
  • Remove shade,
  • Avoid excessive nitrogen applications,
  • Find a balanced fertilizer program like Lawnifi,
  • Early morning irrigation without excessive watering. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water.
  • Remove dead leaves and litter from the lawn and garden.

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, chlorothalonil, fludioxonil, flutolanil, iprodione, Junction®, mancozeb, metconazole, myclobutanil, polyoxin D, propiconazole, pyraclostrobin, thiophanate-methyl, thiram, triadimefon, trifloxystrobin, triticonazole or vinclozolin.

Read product labels thoroughly before application.

Cercospora Leaf Spot
Photo Credit: https://www.lsuagcenter.com/articles/page1494951763101

Pathogen: Cercospora fusimaculan

Appearance/Symptoms:

  • Starts as narrow, dark brown leaf spots,
  • They eventually turn into longer lesions with tan centers surrounded by a darker color.

Affected Grasses:

  • St. Augustine grass.

Time of Year:

  • Spring and summer

Recommended Cultural Treatment/Prevention:

  • Avoid excessive nitrogen applications,
  • Early morning irrigation without excessive watering. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Remove dead leaves and litter from the lawn and garden.
  • Find a balanced fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Fungicides with myclobutanil or thiophanate-methyl. Neem oil is also a great preventative, but doesn’t treat the currently existing cercospora leaf spot.

Read product labels thoroughly before application.

Dollar Spot

Pathogen: Sclerotinia homoeocarpa

Appearance/Symptoms:

  • Small, bleached round spots,
  • Spots range between 5–6 inches in home lawns,
  • Tan-ish color that looks similar to straw,
  • Leaves begin to die after becoming girdled on the surface,
  • You may also see short, fuzzy, mycelium forming on the turf.

Affected Grasses:

You may find dollar spot on a wide variety of turfs. The most common are:

  • Perennial ryegrass,
  • Kentucky bluegrass,
  • Bermuda grass.

Time of Year:

  • The infestation levels are much higher in the spring season as compared to other times of the year. However, temperatures need to exceed a particular barrier for this.

Recommended Cultural Treatment/Prevention:

  • Keep the lawn clean,
  • Don’t cut the grass too short,
  • Dethatch and aerate,
  • Avoid excessive nitrogen applications,
  • Early morning irrigation without excessive watering. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Remove dead leaves and litter from the lawn and garden,
  • Find a balanced fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Fungicides with chlorothalonil, fluoxastrobin or azoxystrobin for controlling dollar spot in your lawn.

Read product labels thoroughly before application.

Fairy Ring

Pathogen: Chlorophyllum spp., Marasmius spp., Lepiota spp., Lycoperdon spp. and others.

Appearance/Symptoms:

  • Patches, rings, or arcs of dead grass,
  • Dark green in color,
  • Grows faster than surrounding turfgrass,
  • Mushrooms or puffballs that grow in arcs or rings.

Affected Grasses:

  • All grasses can be affected by fairy ring.

Time of Year:

  • Fairy ring appears around lumber, tree stumps, logs or other organic matter are located. Rainy weather may also contribute to this disease’s appearance.

Recommended Cultural Treatment/Prevention:

  • Dethatch,
  • Aerate,
  • Early morning irrigation without excessive watering. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Remove dead leaves and litter from the lawn and garden,
  • According to Elliot and Harmon, “If the soil under this dead grass is dry but the soil under healthy grass next to it is wet, then it is necessary to aerate or break up the soil under the dead grass (using a pitchfork). Then a soil-wetting agent can be applied and the ring (and only the ring) watered daily to rewet the soil and encourage turfgrass recovery.” Click to view PDF.

Recommended Chemical Treatment/Prevention:

  • Most fungicides have not been proven effective, although they may inhibit the fungus. An effective fungicide treatment hasn’t been determined yet.
Gray Leaf Spot

Pathogen: Pyricularia grisea

Appearance/Symptoms:

  • Oblong spots on the leaf blade,
  • Spots with tannish centers and a darker ring around the border.

Affected Grasses:

  • Most commonly on St. Augustine grass but occasionally may also be found infecting tall fescue, bermuda grass, centipede grass and ryegrass in home lawns.

Time of Year:

  • When temperatures are between 77–86 degrees Fahrenheit. It is most severe during rainy, humid periods.

Recommended Cultural Treatment/Prevention:

  • Reduced Shade,
  • Early morning irrigation without excessive watering. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Remove dead leaves and litter from the lawn and garden,
  • “The timing of any atrazine application should be chosen carefully, since this chemistry can stress the grass especially when temperatures may climb above 85°F. Atrazine applications made before or during disease-favorable conditions increase the likelihood of severe gray leaf spot symptom development. Spot-treating trouble areas with the herbicide could also be considered.” Click to view PDF.
  • Find a balanced fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, pyraclostrobin, fluoxastrobin, thiophanate methyl, propiconazole or myclobutanil.

Read product labels thoroughly before application.

Gray Snow Mold
Photo Credit: https://hort.extension.wisc.edu/articles/lawn-disease-quick-reference/

Pathogen: T. incarnata and T. ishikariensis

Appearance/Symptoms:

  • Needs at least 60 days of snow coverage to develop this disease,
  • Forms circles or patches at least 3 feet in diameter or more,
  • Turf appears white or gray and matted.

Affected Grasses:

  • Bentgrass,
  • Bluegrass,
  • Fescue,
  • Ryegrass.

Time of Year:

  • Winter or when excessive snow is present.

Recommended Cultural Treatment/Prevention:

  • Mow until growth of the grass stops,
  • Don’t apply nitrogen right before cold temperatures,
  • Improve drainage,
  • Dethatch,
  • Aerate,
  • Remove dead leaves and litter from the lawn,
  • Prune trees and shrubs to increase airflow,
  • Reduce foot traffic,
  • Try to remove snow before it melts.

Recommended Chemical Treatment/Prevention:

Read product labels thoroughly before application.

Helminthosporium Leaf Spot (Bipolaris Leaf Spot)

Pathogen: Bipolaris, Drechslera and Exserohilum spp.

Appearance/Symptoms:

  • Spots that range from tiny to expanded lesions,
  • Brown or purple leaf blades,
  • Purple shade of color on the lawn once it expands,
  • Some areas may turn black,
  • No distinct patterns or patches.

Affected Grasses:

Time of Year:

  • Due to the fact that this disease is caused by different species that thrive in different temperatures, bipolaris leaf spot can occur any time of the year but usually shows up during wet periods around the fall or winter.

Recommended Cultural Treatment/Prevention:

Recommended Chemical Treatment/PRevention:

  • Fungicides with chlorothalonil, fludioxonil, iprodione, mancozeb, myclobutanil, propiconazole, pyraclostrobin, trifloxystrobin, triticonazole or vinclozolin.

Read product labels thoroughly before application.

Large Patch

Pathogen: Rhizoctonia solani

Apperance/Symptoms:

  • Size of damage ranges from a few inches to several yards,
  • Large circles of thin, damaged grass,
  • Can also take the shape of irregularly-shaped patches,
  • Produces bronze-colored borders where the affected grass and healthy turf meet.

Affected Grasses:

  • Large patch can affect all warm season turfgrasses, particularly centipede grass and seashore paspalums. However, it can also be spotted in St. Augustine and zoysia lawns. When large patch affects zoysia grass, it can sometimes be referred to as zoysia patch.

Time of Year:

  • Large patch disease typically occurs in the fall, but may not be spotted until early spring when the lawn begins to come out of dormancy.

Recommended Cultural Treatment/Prevention:

  • Dethatch,
  • Avoid Excessive Nitrogen,
  • Improve drainage,
  • Water lightly and in the early morning. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water.

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, chlorothalonil, fludioxonil, flutolanil, iprodione, Junction®, mancozeb, metconazole, myclobutanil, polyoxin D, propiconazole, pyraclostrobin, thiophanate-methyl, thiram, triadimefon, trifloxystrobin, triticonazole or vinclozolin.

Read product labels thoroughly before application.

Leaf Rust

Pathogen: Puccinia spp.

Appearance/Symptoms:

  • Light yellow spots appear on grass blades during initial phases,
  • In later stages, orange spots appear that run alongside grass blade veins,
  • Orange spots will rub off if you touch them.

Affected Grasses:

  • St. Augustine, zoysia and occasionally ryegrass.

Time of Year

  • Usually occurs from late fall to early spring and shows up the most once temperatures begin warming up again.

Recommended Cultural Treatment/Prevention:

  • A balanced fertilizer program,
  • Reduced shade,
  • Early morning irrigation without excessive watering. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Find a balanced fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, mancozeb, mancozeb plus copper hydroxide, metconazole, myclobutanil, propiconazole, pyraclostrobin, triadimefon, trifloxystrobin and triticonazole.

Read product labels thoroughly before application.

Necrotic Ring Spot
Photo Credit: https://www.canr.msu.edu/ipm/diseases/necrotic-ring-spot

Pathogen: Ophiosphaerella korrae

Appearance/Symptoms:

  • Initial light green patches,
  • Eventually creates rings of brown grass with healthy grass in the middle,
  • These brown rings may turn tan or appear sunken over time,
  • Ring sizes can range from a few inches to several feet over time,
  • Roots, crowns and lower stems appear black or brown from rot,
  • Usually appears 2–3 years after the sod has established.

Affected Grasses:

  • Cool season grasses and primarily Kentucky bluegrass.

Time of Year:

  • During the spring and fall with cool and wet weather.

Recommended Cultural Treatment/Prevention:

  • Water lightly and in the early morning. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Try raising your usual mowing height,
  • Find a balanced fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Thiophanate methyl and azoxystrobin fungicides provide the best curative management while fenarimol, myclobutanil and propiconazole work best preventively.

Read product labels thoroughly before application.

Pink Snow Mold
Photo Credit: https://bygl.osu.edu/node/1465

Pathogen: Microdochium nivale

Appearance/Symptoms:

  • pink, white, or tan patches of dead grass,
  • Matted leaf blades,
  • Damaged spots are surrounded by copper-colored rings in the margins,
  • 2 inches to 10 inches in diameter,
  • Mycelium, or a white, fluffy substance can be observed.

Affected Grasses:

Time of Year:

  • Winter or whenever snow is present or begins to melt.

Recommended Cultural Treatment/Prevention:

  • Continue to mow in the fall,
  • Find a balanced fertilizer program like Lawnifi,
  • Don’t apply nitrogen right before cold temperatures,
  • Improve drainage,
  • Dethatch,
  • Aerate,
  • Remove dead leaves and litter from the lawn,
  • Prune trees and shrubs to increase airflow,
  • Reduce foot traffic.

Recommended Chemical Treatment/Prevention:

  • Fungicides with metconazole, myclobutanil, propiconazole, tebuconazole, triadimefon, triticonazole, iprodione, thiophanate-methyl, fludioxonil, azoxystrobin, fluoxastrobin, pyraclostrobin, trifloxystrobin or chlorothalonil.

Read product labels thoroughly before application.

Powdery Mildew

Pathogen: Erysiphe graminis

Appearance/Symptoms:

  • White grayish spots,
  • Powdery-looking substance,
  • Overtime, it can expand and produce large white or gray spots.

Affected Grasses:

  • Kentucky bluegrass,
  • Fine fescue,
  • Perennial ryegrasses.

Time of Year:

  • When there’s warm, humid weather.

Recommended Cultural Treatment/Prevention:

  • Increase air circulation,
  • Reduce shade,
  • Water lightly and in the early morning. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water.
  • Remove dead leaves and litter from the lawn,
  • Find a balanced fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Fungicides with metconazole, myclobutanil, propiconazole, tebuconazole, triadimefon or triticonazole.

Read product labels thoroughly before application.

Pythium Blight

Pathogen: Pythium aphanidermatum, & Pythium spp.

Appearance/Symptoms:

  • Dark patches,
  • Greasy/gray colored layers,
  • Light brown surface formation,
  • Cotton-like growth,
  • Patchy surfaces.

Affected Grasses:

  • Perennial ryegrass,
  • Creeping bentgrass,
  • Annual bluegrass,
  • Kentucky bluegrass,
  • Tall fescue,
  • Bermuda grass.

Time of Year:

  • During warmer seasons ranging between late spring and early summer.

Recommended Cultural Treatment/Prevention:

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, propiconazole, chlorothalonil, fluoxastrobin, mefenoxam, propamocarb, cyazofamid or fluopicolide.

Read product labels thoroughly before application.

Red Thread
Photo Credit: https://www.canr.msu.edu/news/pinkish_red_strands_in_grass_could_be_red_thread

Pathogen: Laetisaria fuciformis

Appearance/Symptoms:

  • Circular patches or rings,
  • A size of 6 inches to 3 feet in diameter,
  • Off-colored at first then turns yellow or tan,
  • Wilting,
  • Poor growing,
  • Sunken turf,
  • Outer edges may be orange,
  • Turf should be easy to pull up when infected,
  • Rotted roots, crowns or rhizomes.

Affected Grasses:

  • Creeping bentgrass,
  • Annual bluegrass,
  • Kentucky bluegrass,
  • Fine fescue.

Time of Year:

  • Spring and summer

Recommended Cultural Treatment/Prevention:

  • Follow proper irrigation practices,
  • Increase drainage,
  • Dethatch,
  • Aerate,
  • Water lightly and in the early morning. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water,
  • Find a balanced fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Fungicides with metconazole, myclobutanil, propiconazole, tebuconazole, triadimefon, triticonazole, iprodione, thiophanate-methyl, azoxystrobin, fluoxastrobin, pyraclostrobin, trifloxystrobin, flutolanil, penthiopyrad, chlorothalonil, fluazinam or mancozeb.

Read product labels thoroughly before application.

Slime Mold
Photo Credit: https://ohioline.osu.edu/factsheet/HYG-3074

Pathogen: Mucilago, Physarum, and Fuligo spp.

Appearance/Symptoms:

  • Small, round pustules,
  • Pustules can be various colors including purple, gray, white, yellow or orange,
  • This disease does not cause direct harm to the grass, but its coverage causes the yellowing of grass blades due to the shade it creates.

Affected Grasses:

Time of Year:

  • Warm, humid climates with rain in spring or summer.

Recommended Cultural Treatment/Prevention:

  • These molds usually disappear on their own within 2–3 days so no action is needed. If you want to get rid of it quickly because it looks unsightly, consider mowing or washing the grass with water.

Recommended Chemical Treatment/Prevention:

  • Chemical management is not typically recommended or needed.
Spring Dead Spot

Pathogen: one or more species of Ophiosphaerella

Appearance/Symptoms:

  • Bleached, sunken, circular patches on the ground,
  • Ranging between a few centimeters to large patches,

Affected Grasses:

  • Spring dead spot can show up in a number of turfgrasses but is most commonly found in bermuda grass.

Time of Year:

  • Damage occurs during the fall and winter; however, because the turfgrass is usually dormant, the damage doesn’t appear until the spring when the grass begins to green up again.

Recommended Cultural Treatment/Prevention:

  • Find a balanced fertilizer program like Lawnifi,
  • Aerate,
  • Dethatch,
  • Water lightly and in the early morning. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water.

Recommended Chemical Treatment/Prevention:

  • When searching for the best disease control for spring dead spot, there are many options to consider. For best results, you may consider using azoxystrobin or fluoxastrobin for controlling spring dead spot. Spectracide Immunox is labeled for treatment of spring dead spot but may not be as effective in severe cases.

Read product labels thoroughly before application.

Summer Patch
Photo Credit: University of Massachusetts Amherst.

Pathogen: Magnaporthiopsis poae

Appearance/Symptoms:

  • Circular patches or rings,
  • A size of 6 inches to 3 feet in diameter,
  • Off-colored at first then turns yellow or tan,
  • Wilting,
  • Poor growing,
  • Sunken turf,
  • Outer edges may be orange, 
  • Turf should be easy to pull up when infected,
  • Rotted roots, crowns or rhizomes.

Affected Grasses:

  • Creeping bentgrass,
  • Annual bluegrass,
  • Kentucky bluegrass,
  • Fine fescue.

Time of Year:

  • Summer

Recommended Cultural Treatment/Prevention:

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, fluoxastrobin, flutriafol, fluxapyroxad, mefentrifluconazole, metconazole, myclobutanil, penthiopyrad, propiconazole, prothioconazole, pyraclostrobin, tebuconazole, thiophanate-methyl, triadimefon, trifloxystrobin or triticonazole.

Read product labels thoroughly before application.

Take-all Root Rot
Photo Credit: https://www.lsuagcenter.com/topics/lawn_garden/commercial_horticulture/turfgrass/turfgrass-diseases/take-all-root-rot

Pathogen: Gaeumannomyces graminis var. graminis

Appearance/Symptoms:

  • This disease is hard to spot because it attacks turfgrass roots underneath the soil’s surface—not the grass blades. Once the grass blades begin showing signs of stress, the disease has already pretty severely damaged the roots,
  • You may see yellow or light-green patches of turfgrass,
  • Roots become shot and rotted,
  • Grass will thin or become bare.

Affected Grasses:

  • Bentgrass, St. Augustine grass, bermuda grass and centipede grass are susceptible.

Time of Year:

  • During the summer or fall months or when areas receive excessive amounts of rain.

Recommended Cultural Treatment/Prevention:

  • Mow at the turfgrasses proper height,
  • Help your lawn fight stress with a fertilizer program like Lawnifi.

Recommended Chemical Treatment/Prevention:

  • Chemical treatments are rarely effective; however, there are fungicides that can help prevent this disease including azoxystrobin, myclobutanil, propiconazole, pyraclostrobin, thiophanate methyl and triadimefon. Applications should be made one month prior to when damage is seen above ground and should continue for another month after excessive rain has ended.

Read product labels thoroughly before application.

Zoysia Patch (Large Patch)
Photo Credit: https://turfmasterslawncare.com/2021/11/03/zoysia-patch-fungus-in-lawn/

Pathogen: Rhizoctonia solani

Appearance/Symptoms:

  • Size of damage ranges from a few inches to several yards,
  • large circles of thin, damaged grass,
  • Can also take the shape of irregularly-shaped patches,
  • Produces bronze-colored borders where the affected grass and healthy turf meet.

Affected Grasses:

  • Zoysia grass

Time of Year:

  • Large patch disease typically occurs in the fall, but may not be spotted until early spring when the lawn begins to come out of dormancy.

Recommended Cultural Treatment/Prevention:

  • Dethatch,
  • Avoid excessive nitrogen,
  • Improve drainage,
  • Water lightly and in the early morning. Consider conducting an irrigation audit to ensure your lawn is receiving the appropriate amount of water.

Recommended Chemical Treatment/Prevention:

  • Fungicides with azoxystrobin, chlorothalonil, fludioxonil, flutolanil, iprodione, Junction®, mancozeb, metconazole, myclobutanil, polyoxin D, propiconazole, pyraclostrobin, thiophanate-methyl, thiram, triadimefon, trifloxystrobin, triticonazole or vinclozolin.

Read product labels thoroughly before application.

Other Potential Issues

Sometimes it can be difficult to tell what exactly is causing damage to your lawn. Some of the suggestions below could be possible culprits. The best way to find out what’s causing issues in your lawn is by sending a sample into your local extension office.

Now that you understand more about lawn disease and the various shapes they can take, you can begin making proactive steps to prevent outbreaks. If your lawn has experienced disease around a certain time of year before, apply a disease control product at a preventive rate before disease takes hold. Learn more about preventive applications here.

If problems with a certain lawn disease persist, consider rotating fungicides with different active ingredients as the disease may have built up an immunity to one active ingredient over time. Be sure to read product labels thoroughly before application.

Providing your lawn with essential nutrients is vital to maintaining a healthy, strong lawn. Sod Solutions recommends the Lawnifi® Fertilization Program. Lawnifi gives your lawn what it needs in the form of nano-sized nutrients, exactly when it needs it in the form of easy-to-apply monthly applications from March through November.

It’s important to note that even with the use of an improved fertilizer program, the timely application of fungicide is still necessary for overall lawn health. If you fertilize your lawn with nitrogen before applying a fungicide and presently have a lawn fungus, that fungus will expand exponentially, which can be disastrous for your lawn.

Sources:

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