For many homeowners, our lawns have become the crowning jewel of our property. We spend hours fertilizing, mowing, edging, and caring for our tender little grass babies. All of this TLC can make it even more disappointing when turfgrass diseases pop up for seemingly no reason.
Often, these diseases lurk beneath the surface, just waiting for the perfect conditions to attack your luscious grass blades. The good news is with some help and knowledge, you can be ready when these diseases attack!
Below, I have compiled a list of 9 common turfgrass diseases that may pop up in your home lawn. Hopefully, with this list, you can identify and treat any diseases you may find!
Brown Patch
Brown patch is a fungal disease that thrives in high temperatures and humidity.
Brown patch is a fungal disease. This fungus is a saprophyte, which feeds on decaying plant material such as thatch in your lawn. This turf disease will pop up when temperatures reach over 80 degrees and, more often than not, during periods of high humidity.
Brown patch can affect most cool-season grasses but is especially prevalent on ryegrass and tall fescue. Some warm-season grasses, like zoysia grass, can also struggle with brown patch.
Blades of grass infected with brown patch will begin to look wet, then quickly dry, wither, and turn dark brown. The infected areas appear in large round patches on your lawn that range from a few inches in diameter up to 3 feet in diameter. These brown rings will often have a darker grey ring around the outer edge.
Brown patch occurs in the summer months when humidity is high. Cutting back on irrigation can help keep this fungus at bay. Dethatching and aerating your lawn in the spring and collecting your grass clippings will help to keep any decaying plant matter off of your lawn, which this fungus loves to feed on.
You can also apply a preventative application of fungicide if you have dealt with brown patches in the past.
An application of a broad-spectrum fungicide can help to treat and control brown patches.
Granular fungicides can be found at your local hardware store, however calling in a lawn care service to spray and handle the brown patches might be ideal depending on how widespread the spots are.
Dollar Spot
Dollar spot resembles a brown patch but forms smaller spots that can merge if untreated.
Dollar spot is very similar to brown patch in appearance. However, the affected patches are much smaller in area, about the size of a silver dollar. If left untreated, many of these spots may appear and merge to create one more prominent spot.
Dollar spot is most active on warm spring or warm fall days with high humidity and cool nights. Each blade of grass will have a tan marking with red bands on either side of the tan mark. These blades of grass will make up small round spots that can range from the size of a quarter to the size of a silver dollar. In the morning dew, you may see white fuzzy mycelia on top of these spots. This is the fungus actively growing.
Good lawn care practices are the best way to prevent dollar spot patches from popping up in your lawn. Aerating and dethatching your lawn in the spring will bring sufficient airflow to both the leaf blades and the root systems to help keep fungal infections away.
Watering your lawn in the morning is another way to prevent dollar spot. This practice will allow water drops that may be sitting on the grass to evaporate before the evening temperatures set in.
Systemic fungicides and granular fungicides such as fungal control by bioadvanced can help treat this lawn disease. These products can be used to treat fungal diseases, as well as potentially prevent them.
Fairy Ring
Fairy ring is a beneficial soil fungus that enriches the soil and feeds grass.
Fairy ring is a fungal disease that primarily lives in the soil. The fungus will break down organic matter in your soil and create nitrogen as a byproduct, feeding your grass.
This disease is most prevalent in the primary growing season, and doesn’t significantly damage your lawn. Aside from the ring that may die out, the presence of a fairy ring is no big deal.
Fairy ring affects cool-season grasses such as Kentucky and annual bluegrass, perennial ryegrass, tall and fine fescue, and creeping bentgrass.
You may notice irregular or circular rings of grass that is deeper green, and growing taller than the rest of your lawn.
These rings can be small, or they can grow up to 30 feet in diameter. If you begin to experience drought or excessive heat, these seemingly healthy areas will die out leaving a ring of dead grass in your lawn. Occasionally you may see mushrooms appear on the surface in the shape of a ring.
Mowing your lawn regularly is a good way to keep the fairy ring from developing into an issue. Aside from this, make sure your lawn has good airflow by aerating and dethatching every year. Getting your lawn on a regular fertilization schedule will help to strengthen your lawn and keep.
There are no chemical treatments recommended for fairy rings. Try your best to prevent it! The good news is that it does not do too much damage, and will not completely ruin the appearance of your lawn.
Leaf Spot
Leaf spot disease can affect various parts of plants.
There are a few different types of leaf spots, but here, we will lump them together as one. This disease is most active in warm temperatures but survives in cooler temperatures, which makes this disease a bit tricky to keep in check.
Typically, leaf spot diseases only affect the leaf blades. However, an aggressive infestation may affect the crown and root of the plant, which can lead to more significant damage.
While you are inspecting each leaf blade you will first see deep red or purple spots on each blade. As these spots grow and age the center will become tan or straw-colored. As the temperatures heat up the entire blade may turn tan.
Aerate and dethatch your lawn yearly. Another great way to keep leaf spots in check is by keeping your lawn on a watering schedule. If you have an irrigation system this is easy to do. What you want to avoid is lengthy dry periods on your lawn. When you begin to water again after a dry period you can intensify the disease.
If you have identified a leaf spot infestation, hold off on fertilizing your lawn. This will limit the amount of growth your grass will put out while you are treating the disease.
Melting Out
Melting out is a fungal disease resembling leaf spot, prevalent in Kentucky bluegrass lawns.
Melting out is a cool weather fungal disease that closely resembles leaf spot. This is a disease that very strongly favors Kentucky bluegrass, making it very prevalent in home lawns.
The blades of grass will be spotted. From a distance, the infected area may look almost black, or straw-colored. This all depends on the amount of nitrogen in your lawn. It may be difficult to differentiate between leaf spot and melting out. The main difference is that melting out attacks your lawn in the spring and fall, while leaf spot is most active in the heat of summer.
Raising the mowing height during the cooler seasons will alleviate stress on your grass and help to keep this fungus in check. Regular fertilization is very helpful, especially in the cool months of the spring. Be careful when fertilizing in the fall as this could promote too much growth of your grass.
Fungicides such as iprodione or chlorothalonil are the best chemical treatments for melting out.
Powdery Mildew
Powdery mildew affects ornamental plants and lawns, with the turfgrass strain causing significant damage.
You read that right. Not only can powdery mildew go after our ornamental plants, but it is also common on our lawns.
While powdery mildew on plants does not kill them or damage anything but their appearance, the strain of powdery mildew found on turfgrass can be detrimental.
Powdery mildew is most common on cool-season grasses, especially Kentucky bluegrass. The symptoms of this disease can pop up anywhere from April- October but are most likely to be seen in humid temperatures.
Powdery mildew will appear like white or grey dust on the blades of your grass and is most common in shady parts of your yard.
Planting the right type of grass for your yard is crucial to keeping powdery mildew at bay. Perennial ryegrass is a great option for shady yards. Sunlight and increased airflow are also great watts to keep this fungal disease away. Pruning tree branches can help to improve airflow near your grass. Aerating and dethatching can allow your roots to breathe and will create an environment that powdery mildew does not like.
Powdery mildew can be tricky to treat because it is quick to resist fungicides. Enlist the help of a lawn care company if you wish to spray. However, prevention is the best method.
Red Thread
This fungal disease forms circular red or tan patches.
Red thread is a fungal disease that can affect many home lawns. These red or tan infected patches can be circular and reach up to 5 inches. This disease is common at any point in the growing season but is most prevalent when humidity is high.
Red thread affects all cool-season grasses, mainly perennial ryegrass, Kentucky bluegrass, and fine fescue.
Pink or red threads or webbing will present themselves on your grass blades. When your grass is wet the fungus may look shiny, whereas when the grass is dry it may look like your grass has browned out.
Red thread can be a sign of turf that is lacking nitrogen. Be sure you are giving your lawn an adequate amount of fertilizer throughout the year. Do your best to keep your lawn well-watered throughout the summer months. Collect your lawn clippings if you think you may have any fungal diseases, this can prevent spreading.
Typically this disease is not severe and does not require chemical treatment. Treat with a generic lawn fungicide or contact your local lawn care company for help!
Snow Mold
Two types of snow mold, grey and pink, appear due to wet conditions.
There are two common types of snow mold: grey snow mold and pink snow mold. You will notice the symptoms of this fungal disease in the spring when snow is melting away.
The cause for this disease is warm soil, with lots of snow or leaf litter sitting on top of the grass and keeping it wet for a prolonged period.
When your grass become visible after the snow melts grey snow mold will appear as a grey or light brown patch, but will only affect the leaf blades. These patches can range from 3 inches to 24 inches in diameter.
Pink snow mold can affect the crown of the plant which will cause much more damage to your turf. The symptoms of pink snow mold are similar to grey although you may find that the patches have a hint of pink or copper to them. These patches will also be smaller, growing to a diameter of only 10 inches.
Keeping your grass free of snow or wet leaf litter is the best way to prevent this disease. However, if you are not concerned with having a perfect lawn you do not need to worry about this too much. If you wish, applying a fungicide before snowfall is a good way to keep the disease under control.
Treating snow mold should be done using fungicides such as propiconazole, or other granular lawn fungicides.
Summer Patch
Summer patch is a destructive fungal disease that targets the root system of your grass.
Summer patch, as its name indicates, is most destructive in the warm summer months. This fungal disease lives in the soil and affects the roots of your grass plants without much notice before the large patches appear.
Summer patch affects cool season grasses such as fine fescue and Kentucky bluegrass.
Once the weather warms up, look for larger patches of straw-colored grass. These patches could be 3 feet in diameter each, and they can group together taking over a large portion of your lawn.
Unlike many other turfgrass diseases, summer patch is a disease of the roots rather than the leaf blades. This makes aerating your lawn very important. Keeping your lawn a bit longer, 3 inches in height should suffice, you will encourage deeper root growth which will strengthen the overall plant’s ability to fight this disease. Water your lawn in the afternoon, and lightly each day depending on rainfall.
Using a systemic fungicide from your local hardware store may help. However, some of these fungicides require a professional application and it may be safer to call in your local lawn care company.
Final Thoughts
Lawn care has a reputation for being tricky and challenging. This can be true, but there are simple ways to keep your lawn looking beautiful while limiting the time you spend working in your yard. Aerating and dethatching are simple enough to do yourself, but many lawn care and landscaping companies would be happy to perform these services for you.
Take time to make sure the grass seed you sow in your lawn is suitable for your growing conditions. There are grass seeds for drought tolerance, shade tolerance, and even tolerance to some diseases. Planning will help you greatly in the long run!
