Weeds are a common threat to a beautiful lawn, but you should also worry about fungus. Lawn fungus can spread quickly and draw vital nutrients from the grass. 

Here is a closer look at how to identify fungus and stop the threat from taking over.

How to Identify Fungus on your Lawn

Brown patches on grass are just one sign that your lawn is dealing with a fungus problem. You may also notice stringy red threads, mushrooms, and other forms of fungus and fungal diseases.

Understanding common fungal threats can help you identify the issue in your lawn. Some of the most common types of fungus and fungal diseases include:

  • Red thread
  • Fusarium 
  • Dollar spot disease
  • Fairy ring disease
  • Lawn rust
  • Mushrooms

Red thread, lawn rust, fusarium, and other fungal diseases can create brown, orange, or reddish-orange patches in your turf. A brown patch may also be a sign of weak grass instead of a fungal infection. 

Red Thread

Red thread can create brown patches on your lawn. You may also notice reddish-pink threads growing on the tips of the leaves. Red thread fungus typically appears in wet, humid conditions and affects finer fescues grasses most frequently.

lawn disease treatment


Fusarium is a fungal disease that typically spreads due to contaminated garden equipment or infected plants transplanted to a garden or lawn. It may cause your grass to turn yellow and gradually die.

Dollar Spot Disease

Dollar spot disease makes your grass appear dead in small circular patches. You may also notice cobweb-like growth. Dollar spot tends to occur due to excessive moisture but can also be mistaken for drought stressed turf.

Fairy Ring Disease

Fairy ring disease may create rings of brown, wilted grass, or dark green grass. This is more commonly a problem with compacted soil, as the soil prevents water from reaching the grass. It is caused by rotting organic matter in the soil that releases spores, turning the soil hydrophobic.

Mushrooms can also appear in these dry patches.


Lawn Rust

Orange-red growth on your grass blades may indicate lawn rust. It occurs more frequently in areas with high humidity and extended wet periods, especially in the Autumn. It can be a sign of compacted soil.


Mushrooms and large toadstools are also a nuisance in your turf. Luckily, they are rarely a threat to your lawn.

Mushrooms may indicate that your soil is healthy. Yet, people often mow over mushrooms to maintain a cleaner-looking lawn. However, a ring of mushrooms may be a sign of fairy ring.


Common Causes of Fungus in Grass

Fungal diseases and fungal growth typically occur in excessively moist conditions. Your lawn may become saturated with water due to a variety of reasons, such as:

  • Improper mowing
  • Overwatering
  • Compacted soil
  • Excess fertiliser

Addressing these causes helps reduce the risk of fungal growth and protect against brown patches on lawns. 


Overwatering promotes fungal diseases by creating the right conditions for fungus to grow. Excess water is especially a problem if the soil is compacted. 

If you need to water your lawn, do so in the morning. Watering in the morning gives the grass all day to soak up the water.

Compacted Soil

Compacted soil keeps the water from draining properly, which also adds to the moisture content. To avoid excess moisture, aerate your soil with a plug aerator. Plug aerators remove plugs of soil instead of pressing a spike into the ground, which can compress the soil even more. 

Excess Fertiliser

Avoid over fertilising your lawn. Excess fertiliser leads to excess growth, requiring you to mow more frequently. Always follow the manufacturer’s instructions to avoid over applying the fertiliser.

How to Treat Brown Patches in Lawn

Proper mowing, watering, and fertilising help limit the risk of fungus in grass. However, if you already have brown patches or other fungal issues, you need to address the problem to keep it from spreading.

Some fungal diseases can continue to spread until they destroy a lawn. Use the following steps to treat the problem:

  • Use a fungicide to kill the fungus
  • Collect grass clippings when you mow
  • Avoid excess foot traffic on the lawn
  • Repeat the treatments if the fungus returns

The fungal disease may not go away on its own. Apply a fungicide to kill the fungus and begin restoring the health of your grass.

Use a Commercial Fungicide to Kill Fungus

You can use store-bought fungicide or a natural fungicide. Store-bought options come in two styles – contact and systemic.

Contact fungicide is a liquid that coats the blades of grass and kills fungus on contact. Systemic fungicide typically comes in small granules that you spread across the soil. 

Many fungicides are designed as all-purpose fungus killers while others are designed to target specific types of fungi. Always read the label to ensure that the product can treat your problem.

Use a Natural Fungicide to Kill Fungus in Grass

You can also use natural fungicide instead of a commercial product. Natural treatments include:

  • Baking soda and water
  • Neem oil 
  • Compost tea

Mix one tablespoon of baking soda and  5 litres of water. Spray the solution on your lawn every three days until the fungus dies.

Neem oil is also an effective fungicide. Mix four tablespoons of neem oil with 5 litres of water. Spray every few days until the problem is gone.

To use compost tea, use four cups of tea per gallon of water. Compost tea is made from tap water combined with a few cups of organic compost.

Continue to Monitor for Fungal Diseases

After treating the problem, continue to monitor your turf for signs of fungal infections. Some fungal diseases are seasonal and may return the following year, requiring you to repeat the treatment. In the meantime, maintain correct mowing techniques.

If possible, collect grass clippings as you mow. Collecting clippings minimises the spread of fungal diseases, as most types of fungi are easily distributed throughout a lawn. Avoiding excess foot traffic also cuts down on the spread of fungal diseases.


Spotting a brown patch or other fungal threat on your lawn does not mean that you need to kill the grass and start over. You can attempt to treat fungal diseases using commercial or natural fungicide. 

Along with killing the fungus, remember to treat your lawn well. Aerate the soil in autumn, avoid trimming the grass too short, remove dead grass, and avoid over watering or over fertilising.