Best Fungicide for St Augustine Grass 2023: Buyer Guide

Best Fungicide for St Augustine Grass

5 Best Fungicide for St Augustine Grass to Get a Healthier Lawn in 2023: The good thing is that fungal diseases are curable. You can take many measurements to control this. However, the most efficient method is to apply a good fungicide. Have your St Augustine grasses turned brown or yellow? The most probable reason is a fungus attack. It is really heartbreaking to see your lawn like this.

St Augustine grasses are not like every other grass. Hence, finding the best fungicide for St Augustine grass can be challenging.

Well, our expert team has done the research and tests to save you from trouble. Continue reading till the end to find the five best fungicides for St Augustine grasses. But first, let’s learn more about fungal disease to avoid any mistreatment.

Identifying Different Fungal Disease

Before you purchase any fungicide, you need to identify the disease. Various fungal diseases can attack your St Augustine Grass. Using the wrong product may cause disaster on your lawn.

We have discussed some of the most common fungal diseases for St Augustine Grass and how to identify them:

Brown Patch

Rhizoctonia fungus causes the brown patch on St Augustine grass. This mostly happens during the summer. When your grass is affected by a brown patch, you will notice brown dots on the blades. Usually, it takes over some part of your lawn in a circular shape.

Brown patches can spread soon and may kill your grass. Use of fungicide that consists of thiophanate-methyl or propiconazole can be helpful against brown patches.

Grey Leaf

Grey leaf is another common fungal disease for St Augustine grasses. Pyricularia grisea is to blame for this. It starts with a brown dot on the blades. And then continuously gets bigger in grey color with a yellow halo around it.

Regular use of fungicide can help to cure this problem. Azoxystrobin and triadimefon work well against Grey Leaf.

Dollar Spot

Dollar spot is not very common to St Augustine grass. But that doesn’t mean it will not affect your lawn. Sclerotinia homoeocarpa fungus causes dollar spot. When it attacks your lawn, you will notice small circular patches about the size of a dollar coin. The discolored patches may take over a wide area soon. Any good fungicide can help fight the dollar spot.

Take-all Root Rot

Take-all root rot can be a common problem for St Augustine grasses in many areas. You will notice dead patches, small or large, around your lawn. This usually starts from roots, causing the root to turn black or brown. You may not notice it in the early stages. But when you see the dead patches, use a good fungicide ASAP.

Fairy Ring

Basidiomycetes may cause a fairy ring on your lawn. If you see irregular ring-like spots on your lawn, then it is a fairy ring. The color of the ring may be dark green or grey. Use fungicide from a good brand regularly to get rid of this fungal disease.

Besides these fungal diseases, some other diseases may also affect your St Augustine grasses. But that is a rare case. The fungicides we have listed can cure almost every fungal disease.

Types of Commercial Fungicides

When you are looking for fungicide for your lawn, you usually have two options. They are:


Granular fungicides are quite common and have been applied by people for a long time. You have to apply the granules all over the lawn well to get rid of the disease. They work pretty well to get rid of fungicides.

  • Highly efficient.
  • Do not get washed away by rain.
  • Stay active for a long time.
  • Labor-intensive application.
  • May cause odor.


The second option comes in liquid form. You can spray this fungicide and get rid of any fungal disease. Over time, the sprayer has become highly popular because of its convenient usability.

  • Easy application.
  • Less labor-intensive.
  • Do not need extra water to settle.
  • Works fast.
  • May wash away in heavy rain.

5 Best Fungicide for St Augustine Grass in 2023: Top Picks Reviewed

First, identify the disease and then decide whether you want granules or liquid. Now read the list below to find the best fungicides for st Augustine grass:

1. Scotts DiseaseEx Lawn Fungicide – Fungus Control: 


Scott DiseaseEx fungicide is an excellent product to get rid of almost 26 types of fungal disease. Whether it’s a brown patch or fairy ring, this fungicide gets you rid of them all. It comes in granular form and works efficiently.

Often people apply fungicide as a precautionary measurement. If you suspect your St Augustine grass is exposed to fungus, you can apply it beforehand. However, if you fail to prevent the fungus, that is not too late. As soon as you notice fungal disease, apply the Scott DiseaseEx.

Granular fungicides work better if you water them after application. Scott DiseaseEx follows the same principle. The producer claims it starts working within 24 hours after application. Moreover, it remains active for up to 4 weeks.

Check the description for the list of fungal diseases it cures. We highly recommend this, especially if brown patches attack your St Augustine grass.

  • It prevents and cures a wide range of fungal diseases.
  • Works fast.
  • Protects St Augustine grasses from disease for a long time.
  • Excellent for brown patches and grey leaves.
  • Need to apply every few weeks for best results.

2. BioAdvanced 701270A Effective Fungicide: 


The second one comes in a sprayer bottle. So, if you prefer to spray instead of spreading, then this one is a must-try product. This can cure dollar spots, brown patches, red thread, and other fungal diseases that may affect St Augustine grass.

BioAdvanced has a good reputation for producing pesticides and fungicides. You also can purchase their granular fungicide, which is listed in number five. As for the sprayer, it works excellent.

Spraying is convenient with the BioAdvanced. You may worry that rain may wash away the liquid. But its unique formula prevents such problems. Overall, it is one of the best spray fungicides for St Augustine grass.

  • Ready-to-use spray.
  • Protects grasses for up to one month.
  • Rainproof formula.
  • Excellent for brown patches and dollar spots.
  • The spray nozzle is not well designed.

3. Spectracide Immunox Fungus Plus Insect Control For Lawns: 


Spectracide is a popular brand for producing insecticides, fungicides, and other herbicides. The Immunox from them cures fungal disease as well as controls the insects in the lawn.

You can apply this spray formula fungicide on your St Augustine grass to cure brown patches, powdery mildew, and rust. It will also kill insects such as ticks, ants, fleas, etc., on the first contact.

Spectracide Immunox uses a unique formula to work well even during the rain. You may think that it will not work well against fungal disease as it’s focused on three problems. That is not the case. Apply it following the instructions on the user manual, and you will see results soon.

  • Multipurpose product.
  • Easy to apply.
  • Value for money.
  • Rainproof formula.
  • Average efficiency on St Augustine grass.

4. Dow AgroSciences 173917 Eagle 20EW Fungicide:



Have dead patches started to take over your lawn lately? Then Dow AgroSciences can help you to save your st Augustine grass. It cures around 15 fungal diseases with its strong formula. Dollar spots, brown patches, root rot; all will be gone after applying the Eagle 20E Fungicide.

It penetrates the root to kill different fungi efficiently. However, you need to apply this on a 7 to 14 days schedule for effective results. Check the instructions on the user manual for more details on this matter.

The AgroSciences Eagle 20E uses quite a strong formula. We suggest you wear masks and gloves while applying on your lawn. Overall, it is one of the best fungicides for St Augustine grass.

  • The extreme formula for maximum efficiency.
  • Cures the most common fungal diseases.
  • It prevents diseases from coming back.
  • Labor-intensive application.

5. BioAdvanced 701230A Fungicide: Ready-to-Spread Granules: 


As we already told you, BioAdvanced also offers granular fungicides. This one is also highly efficient, as the liquid one. Actually, most of the features of these fungicides are similar. It will cure most of the common fungal diseases that may attack St Augustine grass.

If it rains after applying BioAdvanced Granular Fungicide, it will help the granules to melt and start working. It may take a little time to take effect on the affected area. But if you hold patience, you will see the results.

Applying this once will protect your lawn for at least the next 30 days. Based on your preferences, you can either go for the liquid or the granules. Both work excellently.

  • Ready-to-spread granules
  • Good efficiency
  • Easy to spread
  • Works both in wet and dry lawns
  • Works slowly

Final Words: Best Fungicide for St Augustine Grass

These were some of the best fungicides you can use to save your lawn. We did not make a list long as all these options worked extremely well. If you are still confused about selecting the best fungicide for St Augustine grass, our experts may help you. We have two final recommendations for you.

Scotts DiseaseEx Fungicide: Best Granular Fungicide for St Augustine Grass

If you prefer granular fungicide, then we highly recommend Scotts DiseaseEx. It cures almost every fungal disease that may affect St Augustine grass. Follow the instructions properly, and you can get rid of fungus for a long time. Watering or rain will help the granules to work better after application.

BioAdvanced Effective Fungicide: Best Liquid Fungicide for St Augustine Grass

If you prefer to spray, then there is no alternative to the BioAdvanced sprayer fungicide. It helps prevent and cure various fungal diseases. Besides, protect st Augustine grass for up to one month after application. So, if you apply this product, you can expect to get your green lawn back.

Frequently Asked Questions

How do you get rid of the fungus in St Augustine grass?

Fungus is a major problem for St Augustine grass in lawns. The most effective way to deal with such a disease is to use anti-fungal products. There are many effective fungicides available in the market that you can purchase.

What does fungus on St Augustine look like?

What fungus will look on St Augustine completely depends on which type of fungus attacked the grass? Most of the time, you will see small or large brown patches. Proper treatment can cure St Augustine grass of fungal diseases.

Will St Augustine recover from the brown patch?

Brown patches are the most common problems for St Augustine grasses. The good thing is that brown patches are curable with the right treatment. If you use good fungicide properly, you can expect the grass to recover from the brown patch soon.

Can St Augustine grass be overwatered?

Regardless of the breed, overwatering your grass is always harmful. Hence, try to avoid overwatering St Augustine grass. It may cause root rot.

Elysha Murphy

I'm Elysha Murphy, the creator of Easier Gardening. I am very passionate about gardening, and love sharing everything I learn about them.

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