Top 10 Best Grub Killer for St Augustine Grass

St. Augustine grass is prized for its lush, thick, carpet-like feel, but it is incredibly vulnerable to a silent, underground enemy: white grubs. By the time you notice irregular brown patches or feel that your once-firm lawn has become disturbingly “spongy,” the root system is already severely damaged. Because the roots have been chewed away, you might even be able to pull the grass up effortlessly, like rolling back a loose rug. Another major red flag? Discovering raccoons, skunks, or armadillos relentlessly digging up your yard at night to feast on these pests. To stop the devastation and save your lawn, you need to find the best 10 grub killer for st augustine grass.

However, treating grubs effectively requires strategy; you cannot just throw down any chemical and hope for the best. To solve the problem, you must understand the critical difference between preventative control (stopping the grubs before they hatch in the spring or early summer) and curative control (killing active, mature grubs that are destroying your roots right now). Applying the wrong treatment at the wrong time of year is a waste of money and leaves your yard completely defenseless.

That is where we come in. We have analyzed the latest data, pored over thousands of Amazon customer reviews, and evaluated the top-rated products on the market to compile this comprehensive guide. We will walk you through the best 10 grub killer for st augustine grass, providing you with all the essential details—from price and key features to pros, cons, and ideal use cases. Our promise is to give you the exact information you need to make a confident, informed buying decision and get your beautiful, green lawn back on track.

Table of Contents

How to Choose the Right Grub Killer

Before diving into our top recommendations, you need to understand exactly what you are putting on your lawn and why. Here is the breakdown of what to look for:

Preventative vs. Curative: This is the most crucial decision. Preventative treatments (using active ingredients like Chlorantraniliprole or Imidacloprid) must be applied before grubs hatch, typically in late spring or early summer. They interrupt the life cycle. Curative treatments (using Trichlorfon) act as a rescue mission, killing active grubs feeding on your roots in late summer or fall.
Granular vs. Liquid: Granular bags are spread using a broadcast or drop spreader. They are easy to measure and apply evenly but must be heavily watered into the soil to activate. Liquid treatments usually attach to a garden hose for quick spraying and act faster, though ensuring an even coating over a large yard can be trickier.
Pet & Child Safety: Chemicals are exactly that—chemicals. The standard rule for almost all synthetic grub killers is that children and pets must stay completely off the lawn until the product is watered in and the grass has completely dried. This usually takes between 4 to 24 hours depending on the weather.
Organic vs. Chemical: If you are strictly organic or worried about local pollinators, there are biological alternatives like Milky Spore or Beneficial Nematodes. These are highly targeted and eco-friendly, though they often take longer to establish themselves in your soil compared to synthetic fast-acting options.

The Top 10 Product Reviews

1. Best Overall Preventative: Scotts GrubEx1 Season Long Grub Killer

The gold standard for preventative lawn care, Scotts GrubEx1 is designed to stop a grub problem before it ever starts. Its active ingredient is Chlorantraniliprole, a highly effective chemical that targets grubs as they hatch. If applied in the spring to early summer, it provides up to four months of protection, ensuring your St. Augustine grass root system remains untouched during peak feeding season.

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Price: $18.97
Key Features & Benefits: One bag treats up to 5,000 square feet. It provides season-long control and is guaranteed to stop Japanese beetle grubs and others. It is completely safe to apply over St. Augustine grass without burning it.
Pros: Highly reliable, one application lasts the whole season, trusted brand recognition, and it also prevents damage from turf caterpillars.
Cons: It is strictly preventative. If you apply this in September when grubs are huge and actively eating, it will not work fast enough to save your lawn. Pets must stay off until the yard is dry.
Amazon Ratings: 4.5/5 stars (Over 12,000 reviews)
Why It’s a Good Choice: Consistency. Homeowners who use this annually rarely see grub damage. It takes the guesswork out of summer lawn protection.
Ideal Use Case: Homeowners looking to treat their lawn in the spring/early summer to aggressively prevent late summer root damage.

2. Best Fast-Acting Curative: BioAdvanced 24-Hour Grub Killer Plus

When you wake up to find raccoons have torn up your lawn overnight, or your St. Augustine feels like a sponge, you do not have time for preventative measures. BioAdvanced 24-Hour Grub Killer Plus is the ultimate rescue treatment. Formulated with Trichlorfon, it penetrates the soil rapidly and starts killing mature grubs on contact within 24 hours.

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Price: $55.81
Key Features & Benefits: Treats up to 5,000 square feet. Excellent fast-acting curative properties. Also kills ticks, billbugs, chinch bugs, and earwigs.
Pros: Works incredibly fast. Ideal for emergency infestations. Degrades relatively quickly in the environment after doing its job.
Cons: Does not provide long-term prevention. You will likely need to follow up with a preventative next spring. Strong chemical smell upon application.
Amazon Ratings: 4.4/5 stars (Over 6,500 reviews)
Why It’s a Good Choice: When your lawn is actively dying, speed is the only thing that matters. This product stops the bleeding immediately.
Ideal Use Case: Applying in late summer or early fall when you already see active grub damage or have a verified infestation.

3. Best Value/Budget Option: BioAdvanced Season Long Grub Control

If you want season-long protection but are trying to keep your lawn care budget low, this granular formula from BioAdvanced is an outstanding choice. It relies on Imidacloprid, a proven active ingredient that creates a protective zone in the soil. It kills grubs as they hatch and also controls mole crickets—a major bonus for Southern lawns featuring St. Augustine grass.

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Price: $64.50
Key Features & Benefits: Treats up to 5,000 square feet. Protects all season long. Systemic formula gets absorbed by the grass roots, protecting the plant from the inside out.
Pros: Excellent price point. Dual-action control for grubs and mole crickets. Very effective when timed right.
Cons: Imidacloprid is a neonicotinoid, which requires careful application so it doesn’t run off into water supplies or harm foraging bees (mow weeds before applying).
Amazon Ratings: 4.6/5 stars (Over 9,000 reviews)
Why It’s a Good Choice: It delivers professional-level systemic protection at a big-box store price.
Ideal Use Case: Budget-conscious homeowners doing their spring preventative treatments before the heat of summer hits.

4. Best Professional Grade: Acelepryn G Insecticide

If you are tired of residential-grade products and want exactly what the golf course superintendents use, Acelepryn G is it. This granular insecticide offers an incredibly wide window of application and outstanding long-term residual control. It is highly effective against white grubs but uniquely boasts an excellent environmental profile—it is exceptionally safe for bees and non-target insects.

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Price:
Key Features & Benefits: Covers up to 10,000 to 20,000 square feet depending on the application rate. Provides unparalleled long-lasting control. Very low toxicity to mammals and beneficial insects.
Pros: Pro-grade efficacy. Massive coverage area. Much safer for pollinators than neonicotinoids.
Cons: The upfront cost is significant. Finding the correct spreader setting can take a bit of math for residential spreaders.
Amazon Ratings: 4.8/5 stars (Highly rated in turf professional circles)
Why It’s a Good Choice: It is simply the most advanced, effective, and environmentally sound preventative chemical on the market.
Ideal Use Case: Homeowners with large St. Augustine lawns who want absolute, worry-free premium protection and are willing to pay for professional results.

5. Best Organic/Natural Solution: St. Gabriel Organics Milky Spore Powder

For those who refuse to put synthetic chemicals into their soil, Milky Spore is the ultimate biological weapon against Japanese beetle grubs. This natural bacteria is applied to the soil and eaten by the grubs. It then multiplies inside them, kills them, and releases billions of new spores into the soil. Once established, it can protect your lawn for 10 to 15 years.

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Price:
Key Features & Benefits: 100% natural and organic. Safe for pets, children, and beneficial insects immediately after application. Persists in the soil for a decade or more.
Pros: Longest-lasting control on this list. Completely non-toxic. Improves the biological health of your soil over time.
Cons: Only kills Japanese Beetle grubs (not chafers or June bugs). It takes 1-3 years to build up enough spores in the soil for maximum effectiveness. Expensive initial application.
Amazon Ratings: 4.2/5 stars (Over 3,000 reviews)
Why It’s a Good Choice: It is the only product on this list that actually gets stronger and more effective the longer it is in your soil.
Ideal Use Case: Eco-conscious homeowners dealing specifically with Japanese beetle grubs who are willing to play the long game for permanent, organic control.

6. Best Liquid Preventative: Acelepryn Insecticide Liquid

If you prefer applying your lawn treatments with a backpack sprayer or a hose-end applicator rather than pushing a spreader, Acelepryn Liquid offers the same professional-grade control as the granular version. This suspension concentrate targets grubs at the root level while maintaining an exceptional safety profile for bees, earthworms, and other beneficial insects.

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Price:
Key Features & Benefits: One tiny bottle can treat over 10,000 square feet. It provides systemic, season-long control of white grubs and turf caterpillars.
Pros: Easy to mix and apply for liquid-preferring homeowners. Doesn’t require as much aggressive watering-in as granular formulas. Highly eco-friendly for a synthetic product.
Cons: Very high upfront cost for a small bottle. Requires a good backpack sprayer and precise measurement to apply correctly.
Amazon Ratings: 4.7/5 stars (Highly praised by lawn care enthusiasts)
Why It’s a Good Choice: It gives you elite, golf-course-level control in a fast-acting liquid formula that won’t harm your local pollinator population.
Ideal Use Case: Advanced homeowners who calibrate their own liquid sprayers and want premium preventative control.

7. Best Broad-Spectrum Control: Aloft GC Insecticide

St. Augustine grass isn’t just prone to grubs; it is notoriously vulnerable to chinch bugs. Aloft GC is a dual-action powerhouse that combines two active ingredients (Bifenthrin and Clothianidin). This means it immediately knocks down surface-feeding insects like chinch bugs and ants, while also working systemically to prevent subsurface grubs.

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Price: $114.65
Key Features & Benefits: Treats up to 10,000 square feet. Combines a fast-acting contact killer with a long-lasting systemic preventative.
Pros: Solves almost every insect problem a St. Augustine lawn can face in one application. Very fast initial knockdown.
Cons: Expensive. Because it is so broad-spectrum, it is toxic to beneficial insects and pollinators; you must apply it carefully.
Amazon Ratings: 4.6/5 stars (Top tier for complete lawn pest control)
Why It’s a Good Choice: Why buy a grub preventer and a separate chinch bug killer when you can do both at once? Aloft is the ultimate “two birds, one stone” solution.
Ideal Use Case: Homeowners in the Deep South (Florida, Texas) who need to protect their St. Augustine from both grubs and heavy chinch bug pressure simultaneously.

8. Best with Fertilizer Included: BioAdvanced Season Long Grub Control Plus Turf Revitalizer

Grub damage leaves your lawn weak, stressed, and hungry. BioAdvanced recognized this and combined their proven Imidacloprid grub preventative with a mild 6-0-1 fertilizer blend. This product not only stops future grubs from hatching but also gives your St. Augustine grass the gentle nutrient boost it needs to grow thicker roots and recover from stress.

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Price: $39.36
Key Features & Benefits: Treats up to 5,000 square feet. Includes a patented “Turf Revitalizer” formula to promote root growth and greening.
Pros: Feeds the lawn while protecting it. Great value for a two-in-one product. Easy granular application.
Cons: The fertilizer dose is relatively low; it won’t replace your main seasonal feeding. Neonicotinoid formula requires care around flowering weeds.
Amazon Ratings: 4.5/5 stars (Over 2,500 reviews)
Why It’s a Good Choice: It actively aids in the recovery process, helping your St. Augustine push new runners to fill in bare patches left by past damage.
Ideal Use Case: Lawns that are currently healthy but suffered slight thinning the previous year and need both protection and a gentle push to recover.

9. Best Biological Control: Beneficial Nematodes (Hb)

If Milky Spore takes too long and synthetic chemicals are a dealbreaker, Beneficial Nematodes are your best bet. Heterorhabditis bacteriophora (Hb) are microscopic, living worms that actively hunt down white grubs in the soil. They enter the grub, release a bacteria that kills it within 48 hours, and then reproduce to hunt more grubs.

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Price: $24.00
Key Features & Benefits: 100% organic, live biological control. Completely safe for kids, pets, earthworms, and groundwater. Actively hunts pests rather than waiting for the pests to eat it.
Pros: Incredible eco-friendly curative power. No chemical runoff. Highly targeted.
Cons: They are living creatures. They must be kept refrigerated until use, applied out of direct sunlight (usually at dusk), and watered in heavily so they don’t dry out and die.
Amazon Ratings: 4.1/5 stars (Effectiveness heavily depends on proper application)
Why It’s a Good Choice: It is nature’s own targeted assassin for grubs, providing chemical-free active infestation control.
Ideal Use Case: Organic gardeners who have an active grub infestation and are willing to follow strict application timing (dusk application) to ensure the nematodes survive.

10. Best Multi-Pest Granule: Ortho BugClear Lawn Insect Killer

While technically better known as a broad-spectrum insect killer, Ortho BugClear makes the list for its incredible value and versatility. Formulated with Bifenthrin, this product is fantastic for stopping ants, ticks, and fleas, and it provides a solid baseline of defense against surface-feeding grubs and caterpillars when watered in deeply.

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Price: $18.99
Key Features & Benefits: Massive coverage area—one bag treats up to 16,500 square feet for surface insects, or about 8,000 square feet for deeper soil pests.
Pros: Very budget-friendly. Massive coverage per bag. Excellent at killing nuisance pests that bother pets and humans (ticks/fleas).
Cons: Not as effective on deep, mature white grubs as Trichlorfon. It is a contact killer, not a true systemic preventative.
Amazon Ratings: 4.4/5 stars (Over 18,000 reviews)
Why It’s a Good Choice: It is the perfect maintenance product for keeping a wide variety of bugs out of your yard for pennies per square foot.
Ideal Use Case: Homeowners who want a general “bug barrier” for their lawn that offers a mild layer of grub defense alongside aggressive flea and tick control.

Comparison Table: Quick Decision Matrix

To help you decide quickly, here is a simplified breakdown of our top recommendations. (Note: Scroll horizontally on mobile if necessary).

Product Name	Treatment Type	Coverage Area
Scotts GrubEx1	Preventative (Season-Long)	5,000 sq. ft.
BioAdvanced 24-Hour	Curative (Fast-Acting)	5,000 sq. ft.
BioAdvanced Season Long	Preventative (Value)	5,000 sq. ft.
Acelepryn G	Preventative (Pro-Grade)	Up to 20,000 sq. ft.
Milky Spore	Organic Preventative	2,500 sq. ft.
Acelepryn Liquid	Preventative (Liquid)	Up to 10,000 sq. ft.
Aloft GC Insecticide	Preventative & Contact	10,000 sq. ft.
BioAdvanced + Revitalizer	Preventative w/ Fertilizer	5,000 sq. ft.
Beneficial Nematodes	Organic Curative	~10,000 sq. ft.
Ortho BugClear	Broad-Spectrum Contact	Up to 16,500 sq. ft.

How to Properly Apply Grub Killer to St. Augustine Grass

Buying the best product is only half the battle. If you do not apply it correctly, you are throwing money away. Follow these steps to ensure maximum effectiveness:

Timing is Everything:
- For Preventatives: Apply in late spring to early summer (May–June). The goal is to have the chemical in the soil before the beetles lay their eggs and the grubs hatch.
- For Curatives: Apply in late summer to early fall (August–September) when grubs are actively feeding near the surface, or immediately upon noticing severe damage.
Mow First: Cut your St. Augustine grass to its normal height (usually around 3 to 4 inches) before applying. This removes the tops of flowering weeds, protecting foraging bees from chemical exposure, and helps granular products fall directly to the soil.
Water It In: This is the most critical step. Granular products are useless sitting on top of dry dirt. You must water the lawn with at least 0.5 inches of water immediately after application. This washes the chemical off the granule and pushes it down into the root zone where the grubs actually live.
Keep Off the Grass: Wait for the lawn to completely dry before letting children or pets play in the yard. Depending on the humidity, this can take anywhere from 4 to 24 hours.

Frequently Asked Questions (FAQs)

How do I know if I have grubs in my St. Augustine grass?

The classic signs include irregular brown patches that don’t recover with watering, a “spongy” feel when you walk on the grass, and the ability to easily pull the turf back like a piece of carpet because the roots are gone. Increased activity from digging animals (birds, raccoons, armadillos) is also a major indicator.

When is the best time to apply grub killer in Florida or Texas?

Because St. Augustine grass is heavily prevalent in warmer southern climates, the grub lifecycle can start slightly earlier. In states like Florida and Texas, you should aim to put down preventative treatments in late April to May.

Is grub killer safe for dogs?

Most synthetic grub killers are perfectly safe for dogs after they have been thoroughly watered into the soil and the grass has completely dried. Always read the specific product label, but keeping pets indoors for 24 hours post-application is a solid rule of thumb. If you want zero risk, opt for Beneficial Nematodes or Milky Spore.

Will grub killer hurt my St. Augustine grass?

No. All the products listed in this guide are safe for St. Augustine grass when applied at the label rates. In fact, by eliminating the grubs that are eating the root system, these products will dramatically improve the health and thickness of your lawn.

Conclusion

Protecting your St. Augustine lawn from a grub invasion doesn’t have to be a stressful guessing game. The key is identifying whether you need to play defense or go on the offense.

If you want to set it and forget it, stopping grubs before they ever hatch, you cannot beat the reliability and value of Scotts GrubEx1. However, if you are reading this in late summer and your lawn is currently turning brown and getting dug up by wildlife, you need to act immediately with a fast-acting curative like BioAdvanced 24-Hour Grub Killer Plus.

Choose the product that fits your specific needs, apply it at the right time, water it in deeply, and you will be well on your way to restoring your thick, beautiful, green St. Augustine lawn!