Conquering lawn fungus infections

Written by Ian Thompson

Ian holds a Masters in Turf Management from Sydney University, has over 20 years experience working as a golf course Superintendent, turf manager, product formulation and development. We call him our resident Lawn genius.

Great results with a lawn fungicide comes from a deeper understanding. If you can understand why the disease is affecting your lawns, the reasons for their development, and effective treatment options you’re on the path to a healthy and vibrant lawn.

The Types of Fungus Affecting Lawns

Understanding the types of fungus that affect lawns is crucial for effective prevention and treatment. The two primary categories of lawn fungus include leaf diseases, which affect the blades of grass, and root diseases, which target the essential underground structures.

Leaf Diseases

Leaf diseases manifest as unsightly spots, discoloration, or wilting on the grass blades. Common culprits include gray leaf spot, dollar spot, and various other leaf spots that can mar the once-pristine appearance of your lawn.

Root diseases

Root diseases, on the other hand, attack the vital below-ground structures, hindering the grass’s ability to absorb nutrients and water effectively.


The 3 Most Common Reasons for Lawn Fungus

Understanding the factors that contribute to the development of lawn fungus is key to implementing effective prevention strategies. If you don’t act to remove these then you’re going to enter into an endless disease cycle.

To understand diseases we must understand the concept of the “disease triangle,” which states that the presence of disease is the result of an interaction between the susceptible host (the grass), the pathogen (the fungus), and the environment, all needing to be present for disease to occur


Susceptible host

Both a nutrient-deficient lawn and an overly fed lawn are susceptible to fungal attacks. Grass requires a balanced supply of essential nutrients like nitrogen, phosphorus, and potassium for healthy growth and resilience against diseases. An imbalanced or inadequate nutrient profile weakens the grass, making it more susceptible to fungal infections. A nutrient deficient lawn is under stress and therefore more susceptible to lawn diseases like dollar spot, especially just after rain. Whilst a lawn with excessive new growth can often shade itself, keeping moisture on the leaf making grey leaf spot very common.


Weather Conditions


Weather plays a significant role in the development and spread of lawn fungus. Fungi thrive in humid, warm conditions. Poor air circulation and prolonged periods of high humidity create an environment conducive to fungal growth. Additionally, abrupt changes in temperature or extended periods of rain can contribute to the onset of various lawn diseases.



A mix

Just like humans, when stressed or weakened grass is more prone to diseases. Environmental stressors, such as compacted soil, excessive foot traffic, inadequate sunlight or water, can compromise the grass’s natural processes, making it more susceptible to fungal attacks. Addressing any stressors and promoting overall lawn health is crucial in preventing and managing fungal infections.


Treating Lawn Fungus

Effectively treating lawn fungus involves a multi-faceted approach, combining cultural practices and, if necessary, the application of fungicides. Here are best strategies for treating lawn fungus:


Cultural Practices

Implementing cultural practices is the foundation for preventing and managing lawn fungus. As you have learnt about the disease triangle, ensuring proper lawn health removes the susceptible host from the triangle. So review what could be leading to your lawns health issue, fertilise if it’s hungry, water if it’s dry, if it’s staying wet all day look at improving air circulation and reducing shade by trimming overhanging branches. Mow the lawn at the recommended height for your grass type, and irrigate in the morning to allow the grass to dry before these can all minimise the risk of fungal growth.

If your lawn is in terrible condition or seems to be going backwards then sometimes treatment with a fungicide is an advisable option.


Impala Fungicide

Impala fungicide is a broad-spectrum fungicide effective providing curative and preventative control against various lawn diseases, including leaf spots and root diseases. Its systemic action allows it to be extremely effective. When applying Impala, follow the manufacturer’s instructions carefully to ensure optimal results. This fungicide provides a protective barrier against fungal infections and aids in the recovery of an already affected lawn. We recommend this as the best option and when tank mixed with Lawnganics Vitalise it provides a strong curative fungicide with a nutritional product which helps boosts the natural defensive mechanisms of the plant.


Chlortan Fungicide

Chlortan fungicide is another effective tool in the fight against lawn fungus. It targets a broad range of fungi, offering curative action. As with any fungicide, proper application and adherence to guidelines are crucial for success. Chlortan can be particularly useful when dealing with leaf spot fungal infections.


In conclusion, understanding the types of fungus affecting lawns, the reasons for their development, and effective treatment options is essential for maintaining a healthy and vibrant lawn. By adopting proactive cultural practices and utilising targeted fungicides like Impala and Chlortan, homeowners can effectively manage and prevent the impact of common lawn fungi, ensuring their outdoor spaces remain a source of pride and beauty.

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