Fungal infections are usually the leading cause of lawn diseases. Whilst lawns naturally contain non-harmful fungi that work to maintain the quality and health of the lawn, fungal diseases are mostly caused by a change in environment or season.
These diseases can create brown, yellow, or white areas on a lawn in a circular shape. Without proper treatment, this disease can spread throughout the lawn and to other plants, flowers, and potentially trees.
Fortunately, lawn fungal diseases are generally simple to cure and treat. Some prefer the help of lawn care professionals, but early cases of lawn fungal disease can be treated with fungicides. Fungicides are designed to kill parasitic fungi and prevent regrowth, which can do wonders for eradicating those odd-looking patches on your lawn.
Here are the best fungicides for lawns!
OUR TOP PICK
The Spectracide Immunox Multi-Purpose Fungicide is our top pick because of its versatility. Some cases of lawn fungal diseases can, unfortunately, spread to nearby plants, vegetables, flowers, and shrubs. This fungicide spray concentrate is designed to cure and prevent such diseases. It can be used on vegetables, fruits, trees, shrubs, flowers, and lawns.
As for lawns, this fungicide works to both cure and prevent a range of fungal diseases including brown patch, summer patch, spring dead spot, copper spot, powdery mildew, rust, and more.
It is a spray concentration, so it requires a type of sprayer with water and the recommended amount of concentrate. Then, spray away! For flowers, shrubs, trees, berries, vegetables, and fruits, make sure to follow the instructions to treat fungal diseases in these specific areas.
It is recommended to not allow children, adults, or pets near the treated areas until the fungicide has dried. It is also advised to be cautious around vinyl sliding. Whilst this product is non-staining, there may still be a risk of staining on some areas, so it’s worth testing this on a small area before treating the entire area.
Once the concentrate has dried, this fungicide cannot be washed off by rain and will protect diseased areas for up to 2 weeks. It should be reapplied if it rains before the concentrate has dried completely.
As always, make sure to wear protective gear and to wash your hands thoroughly with soap and water!
- Multi-purpose - Can cure and prevent fungal diseases on lawns, shrubs, flowers, trees, fruits, vegetables, and more
- Easy application and use - Concentration requires water and form of spray pump, comes with easy-to-follow instructions for the chosen area
- Not affected by rain - Once dry, fungicide doesn’t wash off by rain and can protect diseased areas for up to 2 weeks
- Garden sprayer not included - Spraying device must be purchased separately
Best Affordable Granular Fungicide
Scotts is a reputable and trusted brand in the fungicide and lawn care world. This granular lawn fungicide can be used to cure and prevent fungal diseases - it is actually recommended to put on the lawn prior to signs of infection to act as a protective barrier.
This is a granular lawn fungicide that requires a separate spreader to spread the product. The size of your lawn will determine the coverage amount, which is calculated on the Scotts My Lawn app.
One bag of this fungicide can treat up to 5000 square feet of lawn. Scotts also sell a range of spreaders for this function.
This fungicide is ideal for treating a range of over 26 fungal diseases including brown patch, red thread, powdery mildew, summer patch, yellow patch, and more.
As it works as both a treatment and preventative, this is ideal for application in spring when diseases are most likely to occur. The lawn will need another application within 2 weeks to a month depending on the quality of the lawn.
- Affordable - Granular fungicides are generally more expensive, but this is a good budget option
- Treats multiple diseases - Can treat and protect the lawn from 26 fungal diseases
- Long-lasting - Lasts up to 28 days before reapplication
- Don’t use handheld spreader - Spreader must be purchased separately and should not be a handheld spreader to avoid skin contact
Best Fungicide for Lawn and Landscape
Fungal diseases aren’t always exclusive to lawns. Flowers, trees, shrubs, and other plants can all be affected by fungal diseases. It is, therefore, important to find a fungicide that is appropriate for treating and protecting a range of lawns and landscapes.
The Bonide BND150 spray fungicide is ideal for controlling a range of diseases in a variety of garden areas. This versatility is ideal in a fungicide, as it can protect a rose bush from rust as well as a lawn from brown patch.
Not only does this product work as a treatment and a preventative, but it can also be used to encourage fast growth. Ideal for newly planted lawns and flowers!
This is a convenient pre-mixed substance with a hose-end sprayer, so all you need to do is attach the sprayer to a garden hose. The fungicide lasts up to 4 weeks and does not wash away from rain or sprinklers.
- Easy to use - Simply attach the sprayer to a garden hose for convenient application
- Suitable for lawns and landscapes - Ideal for treating a range of diseases on multiple surfaces, including lawns, flowers, trees, and shrubs
- Growth stimulator - Product works as a treatment, preventative, and encourages growth
- Pre-mixed product - Some may prefer to control the concentration of their fungicide
Best Fungicide for Brown Patch
Another granular fungicide, this product is most ideal for treating and preventing brown patch.
Often mistaken for a dry patch of grass, brown patch is a fungal disease caused by humid and hot temperatures. Whilst this fungicide works best for treating brown patch, it is also suitable for around 20 other lawn diseases.
Not only can this fungicide be used on yard lawns, but it is also suitable for golf lawns, outdoor turf areas, sports fields, and more. This is ideal for preventing and treating fungal diseases on a range of public lawn areas to keep everyone, and the lawn, safe.
Whilst some may shy away from granular fungicides, this product’s granules are shaped to minimize and prevent excessive dust. They are also lightweight granules, which are designed to cover a wide area of lawn.
- Ideal for brown patch - Treats and prevents over 20 fungal diseases, especially brown patch
- Suitable for a range of lawns - Ideal for yard lawns and public turf lawns
- Great for humid areas - Designed to target brown patch in particular, this is ideal for hot and humid environments
- Dollar Spot disease - Not suitable for controlling or treating Dollar Spot disease
Best Fungicide for Insect Control
Any garden owner will know that insects can be as pesky as fungal diseases. Unfortunately, not all fungicides are designed to kill harmful insects in the same way that they are designed to kill lawn diseases. This fungicide, however, is an exception.
Not only can this product kill and protect your lawn against diseases such as brown patch and rust, but it can also kill more than 20 harmful insects when in contact.
This is ideal for maintaining the quality of both your lawn, flowers, shrubs, and trees. Of course, regular insects are great for the general maintenance of a garden, but harmful insects can be a pain to get rid of.
This fungicide/insect repellent is a ready-to-spray product that only needs to be attached to a garden hose to work. It can treat up to 2,500 square feet of lawn and should be reapplied every 2 weeks.
- Easy to use - Simply connects to a garden hose to cover diseased areas
- Insect repellent - Kills and protects against both lawn diseases and harmful insects
- Suitable for multiple surfaces - Protects lawns, shrubs, bushes, trees, flowers, and more
- Short lifespan - Only lasts up to 2 weeks before reapplication
Best Fungicide for Lawns Buying Guide
Fungicides are a great way to kill harmful fungal pathogens without damaging the quality of the lawn or other areas.
It is important to know the different types of lawn diseases that could affect the health of your entire garden, and how fungicides can work to improve it.
Types of Lawn Disease
There are many different types of lawn disease, but here are the most common ones.
Brown patch is the most common lawn disease which occurs during humid and hot environments.
It is identified by a large, roughly circular area of dry brown grass. The ring of the irregular circle might have patches of emptiness if the disease has been active for a long time.
Another common disease, powdery mildew can occur on lawns, shrubs, bushes, flowers, and more.
It occurs in areas of poor ventilation and wet weather and appears white and dusty in areas. Luckily, it doesn’t cause long-term damage.
Rust on a lawn looks like irregular yellow patches. As you walk through active rust areas, you may see dusty bits of yellow on your shoes as the disease flakes off the grass blades. This can be caused by humid, wet areas.
Red thread isn’t necessarily the most damaging disease, but it will make your lawn more susceptible to pests and other diseases. As the name suggests, red thread can be identified by a red-ish patch of grass.
At a closer glance, the blades will look yellow or bleached. Red thread thrives in warm days and moist evenings.
Snow mold comes in either gray snow mold or pink snow mold diseases. Gray snow mold occurs underneath the snow, whilst pink snow mold can occur in cold and wet environments.
This usually occurs in spring when the snow has begun to melt. Both are identifiable by the color in their names.
Causes of Lawn Diseases
The majority of lawn diseases are caused by a change of weather and season conditions or an imbalance of fungi. As lawns naturally contain non-harmful fungi, this shouldn’t be killed upon sight as this fungus is there to maintain the health and nutrition of the lawn.
Harmful fungi, however, need to be taken care of before the disease spreads.
Different lawn diseases are caused by different weather conditions. For the most part, lawn diseases are caused by overwatering in wet environments. This can include melting snow, humid areas, and excessive use of sprinklers.
Much like how plants will develop root rot if they are left in a poorly ventilated and over-watered pot of soil, lawns will develop lawn diseases if their area is too moist.
How to Identify Lawn Diseases
Fortunately, lawn diseases are easy to spot, which makes treatment usually straightforward. It is important to understand the quality of your lawn depending on what type of grass you have, as this may indicate what diseases are more likely to occur.
For example, necrotic ring spots are more likely to damage Kentucky Bluegrass than other lawn types.
You will naturally notice irregular areas of discoloration or shape in your lawn. Some lawn diseases will appear in dark sludgy areas or areas of patchiness.
From then, you can do research on what the type of lawn disease looks like. This can be done by looking online or by hiring a professional if the case is serious.
How to Treat Lawn Diseases
Of course, fungicide is an ideal way to quickly kill lawn diseases and to prevent your lawn from developing more in the future. Some fungicides will offer growth stimulators and insect repellents as well, which is an added bonus to the maintenance of your garden.
As lawn diseases are mostly caused by excessive amounts of water or food, make sure to avoid overwatering or overfeeding your grass. On the other hand, underwatering and underfeeding your lawn can create an ideal haven for fungal diseases to thrive.
It is therefore important to get the balance right when you notice signs of fungal disease and to stop yourself from watering these areas.
For small areas of lawn disease, a fungicide isn’t necessary. Instead, your lawn will benefit from organic treatments such as compost tea or neem oil. Fungicide, after all, is designed to treat an expansive area of land. And, of course, if in doubt, hire a professional.
How to Avoid Lawn Diseases
Here are our top tips to prevent and avoid lawn diseases:
- Don’t overwater or overfeed a lawn
- Don’t repeatedly walk on snow on a lawn
- Provide good air circulation for small lawns by not covering the sides with tall trees and shrubs
- Keep your lawnmower blades sharp
- Nitrogen will provide green grass but will increase the chances of fungal diseases
- Use organic fertilizers and materials rather than artificial chemicals
- Choose a grass type that works well with your climate
- Fungicides can be used as a preventative measure to stop lawn diseases from growing, but they don’t need to be used all the time - remember, fungicides are harmful to touch and consume by humans and animals!
Can you put too much fungicide on your lawn?
Fungicides are high in chemicals that need to be concentrated with water because too much will cause more damage than good.
Whilst an excessive amount of fungicide will kill the fungal disease, it will also kill the surrounding area - potentially including nearby flowers, shrubs, and trees.
Is liquid or granular fungicide better?
It mostly comes down to personal preference. However, liquid fungicides are generally preferred for their convenience. Some liquid fungicides are pre-mixed whilst others are a concentrate, which makes it easier to control how much product is being used on the chosen area of lawn.
Granular fungicides work just as well, but they need to be applied to the lawn with a spreader and watered down afterward, which is less convenient than liquid fungicides.
How long does lawn fungicide take to work?
Lawn fungicides should begin to treat the diseased area within 24 hours. Results should be obvious after 3 or 4 weeks, where reapplication can occur if the disease is still prevalent.
If water touches the fungicide before it properly dries (whether from rain or a sprinkler), it should be reapplied. After it has dried, the fungicide will not wash off from water.
Does vinegar kill lawn fungus?
For small areas of lawn disease, vinegar is a useful home remedy. Vinegar is a handy treatment for mold and mildew inside a home from moist conditions such as a bathroom or kitchen, and the same applies to small diseased areas of lawns.
However, for larger areas of disease, vinegar might not be strong enough.
Will grass grow back after fungus?
If treated properly before and after the fungus has been cured, grass can grow back within 2 to 3 weeks.
Preventative measures would need to be taken to avoid regrowth of the disease, which includes not overwatering or feeding the area. In extreme cases, grass will take longer to grow back.