How to Prevent and Treat Lawn Diseases

Lawn diseases are caused by fungi that infect the grass and cause various symptoms, such as discolouration, patches, spots, rings, or mould. Lawn diseases can affect the appearance, health, and quality of your lawn, and may even kill the grass if left untreated.

In this article, you will learn about the common types of lawn diseases, how to identify them, and how to prevent and treat them with Handy Andy Lawn Care’s expert tips.

Key Takeaways

Lawn diseases are caused by fungi that infect the grass and cause various symptoms, such as discolouration, patches, spots, rings, or mould.
Lawn diseases can be prevented by following good lawn care practices, such as mowing, watering, fertilising, aerating, and removing thatch.
Lawn diseases can be treated by applying fungicides, improving drainage, removing infected grass, and overseeding.
Handy Andy Lawn Care can help you diagnose and treat lawn diseases, as well as provide regular lawn maintenance and service.

Common Types of Lawn Diseases

There are many types of lawn diseases, but some of the most common ones are:

Brown patch: This disease causes circular or irregular patches of brown, dead grass surrounded by a dark ring. It usually occurs in warm and humid weather, and affects cool-season grasses, such as ryegrass, fescue, and bluegrass.
Dollar spot: This disease causes small, circular spots of tan or straw-coloured grass that are about the size of a coin. It usually occurs in warm and dry weather, and affects all types of grasses, especially those that are low in nitrogen.
Fairy ring: This disease causes rings or arcs of dark green grass, mushrooms, or dead grass. It usually occurs in moist and fertile soil, and affects all types of grasses. The fungi that cause this disease live in the soil and feed on organic matter, such as wood or thatch.
Fusarium patch: This disease causes small, circular patches of yellow, brown, or pink grass that may have a white or pink mould on the surface. It usually occurs in cold and wet weather, and affects cool-season grasses, such as bentgrass, ryegrass, and fescue.
Leaf spot: This disease causes small, oval or circular spots of purple, brown, or black on the grass blades. It usually occurs in warm and humid weather, and affects all types of grasses, especially those that are stressed by drought, heat, or mowing.
Powdery mildew: This disease causes a white or grey powdery coating on the grass blades, especially on the shaded areas. It usually occurs in cool and humid weather, and affects cool-season grasses, such as bluegrass, fescue, and ryegrass.
Red thread: This disease causes patches of pink or red grass that may have thin, thread-like structures on the tips of the grass blades. It usually occurs in cool and wet weather, and affects cool-season grasses, such as fescue, ryegrass, and bluegrass.
Rust: This disease causes small, yellow or orange pustules on the grass blades that may rub off on your hands or shoes. It usually occurs in late summer or autumn, and affects all types of grasses, especially those that are low in nitrogen or water.
Slime mould: This disease causes patches of white, yellow, or black slime or mould on the grass blades. It usually occurs in warm and wet weather, and affects all types of grasses. The slime or mould is actually a type of fungus that grows on the surface of the grass, and does not harm the grass itself.
Snow mould: This disease causes patches of white, pink, or grey mould on the grass after the snow melts. It usually occurs in cold and wet weather, and affects cool-season grasses, such as bluegrass, fescue, and ryegrass.

How to Prevent Lawn Diseases

The best way to prevent lawn diseases is to follow good lawn care practices, such as:

Mowing: Mow your lawn regularly, but not too short or too often. The ideal height for most grasses is between 2.5 and 3.5 inches. Mowing too short can stress the grass and make it more susceptible to diseases. Mowing too often can remove too much leaf tissue and reduce the photosynthesis of the grass. Use a sharp blade to avoid tearing the grass and creating wounds for the fungi to enter. Also, avoid mowing when the grass is wet, as this can spread the fungal spores.
Watering: Water your lawn deeply, but not too frequently. The ideal amount of water for most grasses is between 1 and 1.5 inches per week, depending on the soil type and weather conditions. Watering too frequently can create a moist and humid environment for the fungi to thrive. Watering too shallowly can cause the roots to grow near the surface and make the grass more vulnerable to drought and heat stress. Water your lawn in the morning, so that the grass can dry before the night. Avoid watering in the evening, as this can leave the grass wet and prone to diseases.
Fertilising: Fertilise your lawn moderately, but not too much or too little. The ideal amount of nitrogen for most grasses is between 2 and 4 pounds per 1000 square feet per year, depending on the grass type and soil test results. Fertilising too much can cause excessive growth and make the grass more susceptible to diseases. Fertilising too little can cause nutrient deficiency and make the grass more vulnerable to stress. Fertilise your lawn in the spring and autumn, when the grass is actively growing. Avoid fertilising in the summer, as this can increase the heat and drought stress of the grass.
Aerating: Aerate your lawn annually, or as needed, to improve the soil structure and drainage. Aeration is the process of removing small plugs of soil from the lawn, creating holes that allow air, water, and nutrients to reach the roots. Aeration can help reduce soil compaction, thatch accumulation, and waterlogging, which can all contribute to lawn diseases. Aerate your lawn in the spring or autumn, when the grass is actively growing. Avoid aerating in the summer, as this can stress the grass and expose the roots to heat and drought.
Removing thatch: Thatch is the layer of dead and living organic matter that accumulates between the soil and the grass. Thatch can be beneficial, as it can provide insulation, cushioning, and nutrients to the grass. However, too much thatch can be harmful, as it can prevent air, water, and nutrients from reaching the soil, create a favourable environment for fungi, and harbour insects and pests. Thatch can be removed by raking, dethatching, or aerating. The ideal thickness of thatch for most grasses is between 0.5 and 1 inch. Thatch can be removed in the spring or autumn, when the grass is actively growing. Avoid removing thatch in the summer, as this can stress the grass and expose the soil to heat and drought.

How to Treat Lawn Diseases

If your lawn is infected by a disease, you can treat it by applying fungicides, improving drainage, removing infected grass, and overseeding. Here are some tips on how to treat lawn diseases:

Applying fungicides: Fungicides are chemicals that can kill or inhibit the growth of fungi. Fungicides can be effective, but they should be used as a last resort, as they can also harm the beneficial microorganisms in the soil, and may have negative effects on the environment and human health. Fungicides should be applied according to the label instructions, and only on the affected areas. Fungicides should be applied when the weather conditions are favourable for the disease, and when the grass is actively growing. Fungicides should be applied with caution, and only after identifying the type of disease and consulting a professional.
Improving drainage: Drainage is the ability of the soil to allow excess water to flow away from the surface. Drainage can be improved by aerating, adding organic matter, or installing drainage systems. Improving drainage can help reduce the moisture and humidity that favour the fungi, and prevent waterlogging and root rot. Drainage can be improved in the spring or autumn, when the soil is moist and workable. Avoid improving drainage in the summer, as this can dry out the soil and stress the grass.
Removing infected grass: Infected grass is the grass that shows the symptoms of the disease, such as discolouration, patches, spots, rings, or mould. Infected grass can be removed by raking, mowing, or digging. Removing infected grass can help prevent the spread of the disease.
Overseeding: Overseeding is the process of sowing new grass seeds over the existing lawn, to fill in the bare or thin areas, and improve the density and diversity of the grass. Overseeding can help restore the health and appearance of the lawn, and introduce more disease-resistant grass varieties. Overseeding can be done in the spring or autumn, when the soil temperature and moisture are optimal for seed germination. Overseeding should be done after aerating, dethatching, or mowing, to ensure good seed-to-soil contact. Overseeding should be followed by watering, fertilising, and mowing, to ensure good seed establishment.

Conclusion

Lawn diseases are a common problem that can affect the beauty and quality of your lawn. However, with proper lawn care and maintenance, you can prevent and treat lawn diseases effectively. By following the tips in this article, you can keep your lawn healthy and green all year round.

If you need professional help with diagnosing and treating lawn diseases, or with regular lawn service and maintenance, you can contact Handy Andy Lawn Care. We are a trusted and experienced lawn care company that can provide you with the best lawn solutions for your needs.