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If you have St. Augustine grass, grub damage can show up quickly as thinning patches, wilting, or spongy turf in spring and early summer. Choosing the right grub killer for St. Augustine grass matters because this turf type can be sensitive to certain treatments and cultural stresses. You want a product that controls larvae effectively without harming the grass or disrupting beneficial soil life. This guide covers our seven shortlisted options that are suited to the St. Augustine use case. We evaluated each on factors such as control window, turf safety, and ease of application so you can choose a product that fits your lawn care schedule. Read on to see how the options compare and what to consider for treating grubs in St. Augustine lawns.
Top Picks at a Glance
| Best Overall The best all-around choice for most situations | BioAdvanced Season Long Grub Control Plus Turf Revitalizer Granules, 24 lb |  |
| Best Quality Built to a higher standard if you want something more solid | The Andersons DuoCide Lawn Insect Control Granules (18 lb) |  |
| Best Value The sweet spot between price and what you get | BioAdvanced Season Long Grub Control Granules, 10 lb |  |
| Best Budget The cheapest option that still gets the job done reliably | Sevin Insect Killer Granules II, 10 lb |  |
| Highest Rated A top-rated pick with lots of positive feedback | The Andersons GrubOut Plus Lawn Food 17-0-3 (40 lb) |  |
| Most Popular A crowd favorite that many people choose with confidence | Scotts GrubEx1 Season-Long Grub Killer (covers 5,000 sq. ft.) |  |
| Best Seller A high-volume bestseller chosen again and again | Ortho BugClear Lawn Insect Killer, 20 lb. |  |
BioAdvanced Season Long Grub Control Plus Turf Revitalizer Granules, 24 lb
| Unit Count | 384 Ounce |
|---|---|
| Item Form | Granules |
| Target Species | Insects |
| Item Weight | 24 pounds |
| Active Ingredient | Imidacloprid 0.25% |
This 2-in-1 granular product creates a season-long protective zone in the soil to control white grubs and several other lawn pests with a single application from spring through late summer. You spread it across turf, around trees and shrubs, or in ground covers at the recommended rate and the active ingredient targets grubs, mole crickets, billbugs and European crane fly larvae before they cause visible damage. The included 6-0-1 root booster supplies low-level nutrients aimed at strengthening root systems so damaged or thin areas can recover more quickly. For homeowners with St. Augustine grass, the single-application convenience and multi-pest coverage make it practical for routine grub prevention and lawn recovery projects. Important limitations are that it contains the insecticide imidacloprid so you must follow label restrictions for application timing, rates, and any local use exclusions, and it is a preventive/early-season tool rather than a rapid repair product for large, already-dead turf areas.
Best for: Homeowners who want a straightforward, preventive treatment to protect and gradually revitalize their St. Augustine lawn with one seasonal application.
Less Ideal for: People needing immediate restoration of large dead patches or those who avoid neonicotinoid insecticides should consider other options.
- Single spring-to-late-summer application provides season-long grub protection
- Controls multiple soil-dwelling pests beyond white grubs
- Contains a 6-0-1 root booster to help strengthen and recover stressed turf
- Suitable for use on lawns, ground covers, flower beds, and around trees and shrubs
- Contains the insecticide imidacloprid which requires following label precautions and local regulations
- Not an instant fix for areas where turf is already dead or severely damaged
Verdict: A convenient single-application granular that prevents grubs and helps strengthen St. Augustine turf for seasonal protection and gradual recovery.
The Andersons DuoCide Lawn Insect Control Granules (18 lb)
| Item Form | Granule |
|---|---|
| Coverage | 9000 sq ft |
| Active Ingredients | bifenthrin |
| Unit Count | 288 Ounce |
The Andersons DuoCide is a granular lawn insect control product designed to kill pests both above and below the turf with a single application. You spread the DG granules evenly over the lawn and water them in so the active ingredients move into the soil and the turf surface, which targets grubs, ticks, fleas, fire ants, mole crickets and many other listed pests. The formula combines bifenthrin and carbaryl, giving broad-spectrum knockdown and residual activity that suits season-long problem control when applied according to label directions. The 18 lb bag covers up to 9,000 square feet, so it is practical for large yards and properties where professional‑level performance is the priority. Important limitations are that it contains professional insecticides and requires careful handling and protective gear, and it is not labeled for sale in California, so users must follow all safety and local-use restrictions. Expect effective, long-lasting pest reduction when used as directed and integrated with proper watering and turf care.
Best for: Buyers who prioritize professional-grade, broad-spectrum pest control for medium to large lawns and want a single application solution for both surface and soil pests.
Less Ideal for: Homeowners seeking organic or low-toxicity pest control, owners of very small or containerized lawns, or anyone unable to follow safety precautions for concentrated insecticides.
- Broad-spectrum control targeting more than 50 common lawn pests including grubs, ticks and fire ants
- Dual active ingredients (bifenthrin and carbaryl) for contact and soil activity
- DG granule formulation disperses quickly and is moved into the soil with watering
- Large coverage per bag suitable for up to 9,000 sq ft, good for large lawns
- Contains strong insecticides that require protective equipment and careful handling
- Not available for sale in California
Verdict: Choose DuoCide when you need a single, professional‑strength granular treatment that controls a wide range of lawn pests across a large yard.
BioAdvanced Season Long Grub Control Granules, 10 lb
| Unit Count | 160 Ounce |
|---|---|
| Item Form | Granules |
| Target Species | Insects |
| Active Ingredients | Lambda-cyhalothrin |
BioAdvanced Season Long Grub Control is a granular insecticide formulated to protect lawns from grubs and a long list of surface and soil pests with a single seasonal application. You apply it with a rotary or drop spreader across the lawn, then water lightly to activate the product and create a protective band in the turf. The formula lists lambda-cyhalothrin as the active ingredient and is marketed to kill grubs plus pests such as chinch bugs, mole crickets, ants and ticks, which makes it useful whether damage originates belowground or above. For homeowners managing St. Augustine grass, a single-treatment approach reduces repeat applications and chore time. Limitations to note are that it is a chemical treatment requiring careful application to avoid non-target exposure and it does not list precise application rates for every turf type on the label text provided here, so follow label directions closely. This product is best used as a preventive seasonal treatment rather than a spot fix for established heavy infestations.
Best for: Homeowners who want a low-effort, preventive grub treatment for their lawn and prefer a single seasonal application to reduce maintenance time.
Less Ideal for: People seeking organic or non-chemical grub solutions or those needing an immediate curative treatment for a severe, existing infestation.
- One seasonal application designed to provide season-long control
- Targets a broad range of lawn pests above and below the soil
- Granular form works with common spreaders for even coverage
- Activates with light watering to form a protective barrier
- Contains a synthetic pyrethroid active ingredient that requires careful handling and runoff avoidance
- Label details for turf-specific rates are not included in the provided product text
Verdict: Choose this product if you want a one-application, season-long granular treatment to prevent grubs and a wide range of lawn pests with minimal repeat applications.
Sevin Insect Killer Granules II, 10 lb
| Item Form | Granules |
|---|---|
| Target Species | Insects |
| Active Ingredients | Zeta-Cypermethrin, Bifenthrin |
| Item Weight | 10 pounds |
Sevin Insect Killer Granules II is a 10 pound granular insecticide designed for broadcast application to lawns, gardens, and around ornamental plants and edibles. You apply it with a broadcast or belly spreader, water it in immediately, and it works by contact to kill insects both above and below the soil surface, with protection that can last up to three months. The product lists active ingredients Zeta-Cypermethrin and Bifenthrin, and is labeled for use on a long list of fruits and vegetables plus turf, which makes it handy for one product to treat multiple areas. Its granular form is easy to spread and avoids mixing liquids, and the directions include specific rates so you can treat sized areas efficiently. Important limits are safety and pollinator concerns: do not spray open blooms and follow label precautions to avoid inhalation or skin contact. Also, it is a broad-spectrum synthetic insecticide, so gardeners seeking strictly organic or targeted beneficial-friendly options should consider alternatives.
Best for: Homeowners and lawn caretakers who want an affordable, easy-to-apply granular insecticide that protects turf and edible gardens with a single product.
Less Ideal for: Gardeners focused on organic or pollinator-friendly pest control or those who need ultra-targeted biological controls should look elsewhere.
- Covers lawns, ornamentals and 175+ listed fruits and vegetables with a single product
- Granular form is easy to apply with a broadcast or belly spreader and does not require mixing
- Provides contact kill against over 100 insect pests and can protect up to three months
- Clear application instructions and specified rates for treating defined square footage
- Contains synthetic pyrethroid active ingredients that can harm beneficial insects if used on open blooms
- Requires careful handling to avoid inhalation or skin contact and to protect children and pets
Verdict: A cost-conscious, easy-to-use granular insecticide that protects lawns and edible gardens from a wide range of common pests.
The Andersons GrubOut Plus Lawn Food 17-0-3 (40 lb)
| Item Form | Granules |
|---|---|
| Target Species | Insects |
| Special Features | organic |
| Unit Count | 640 Ounce |
The Andersons GrubOut Plus Lawn Food 17-0-3 is a granular lawn product that combines fertilizer with an insect control agent so you can feed turf and prevent or treat grub damage in a single application. It is typically broadcast over established lawns or applied as a spot treatment around ant mounds and then watered in immediately. Key features include a 17-0-3 nutrient ratio for basic turf feeding, labeled timing windows for preventive grub control, and instructions for spot treatments of ants and other insects. In practice this product simplifies seasonal lawn care by reducing the need to buy a separate grub treatment while delivering routine nitrogen to maintain green, thick grass. Important limitations are state sale restrictions that exclude several states and the need to follow label timing and watering-in directions precisely for effective grub control. Also it is a large 40 pound bag intended for whole-yard use rather than small urban lawns or container plantings.
Best for: Homeowners who prioritize reliable, season-long grub prevention and want a single product to both feed and protect established turf, especially for whole-yard applications.
Less Ideal for: Gardeners with very small lawns, container plantings, or buyers located in states where the product is restricted should choose a different, legally available treatment.
- Two-in-one formula combines turf fertilizer with grub and insect control
- Professional-grade nutrient ratio designed for established lawns
- Can be used preventively or applied when grub damage is first noticed
- Instructions include spot-treatment guidance for ants and other pests
- Not available for sale in several states so regional legality must be checked
- Requires immediate watering-in after application for effectiveness
Verdict: If you want dependable combined turf feeding and preventative grub control for an established lawn, this single 2-in-1 granular product makes seasonal maintenance simpler and more reliable.
Scotts GrubEx1 Season-Long Grub Killer (covers 5,000 sq. ft.)
| Item Form | Granules |
|---|---|
| Target Species | Insects |
| Active Ingredients | Chlorantraniliprole |
| Unit Count | 229.6 Ounce |
Scotts GrubEx1 is a granular, season-long insecticide intended to protect turf by killing grubs and other soil-feeding larvae before they damage roots. It is applied to a dry lawn in spring or early summer using a broadcast or drop spreader and then watered in to carry the active ingredient into the root zone. The product lists chlorantraniliprole as the active ingredient and claims up to four months of control after one application, which makes it a low-maintenance option for routine lawn care. It also controls caterpillars, May/June beetle larvae, billbugs, and suppresses chinchbugs, so it addresses multiple common pests in one treatment. Practical benefits include one-year application limits and clear spreader settings recommended by the manufacturer, which simplify dosing. Limitations are that it must be watered in after application to activate, it is for an annual application only, and it targets soil-dwelling larvae rather than surface-feeding insects, so additional products may be needed for other pest problems.
Best for: Homeowners who prioritize predictable, low-effort grub prevention and want a reliable, season-long solution they can apply as part of routine lawn maintenance.
Less Ideal for: People needing immediate knockdown of active surface pests or those who prefer treatments that can be applied multiple times per season should consider alternate products.
- Single application provides up to four months of grub control
- Covers 5,000 sq. ft. per 14.35 lb. bag, suitable for typical residential lawns
- Targets multiple turf pests beyond grubs, including caterpillars and billbugs
- Manufacturer gives specific spreader settings to simplify correct application
- Requires watering in after application to activate protection
- Designed for one application per year so it is not a quick fix for active heavy infestations
Verdict: Choose this product if you want a straightforward, single-application granular treatment that prevents grubs and several other lawn larvae for an entire season.
Ortho BugClear Lawn Insect Killer, 20 lb.
| Item Form | Granules |
|---|---|
| Target Species | Insects |
| Coverage | Treats up to 33,000 sq ft |
| Residual Control | Up to 6 months (ants), 3 months (other listed pests) |
Ortho BugClear Lawn Insect Killer is a 20 lb. granular treatment for lawns and landscape beds that targets ants, ticks, fleas, grubs, armyworms, and other listed pests. You apply it with a broadcast spreader, water it in, and the formula begins killing on contact within minutes for many pests while leaving a residual barrier that can last up to six months against ants and about three months for other insects. The product covers large areas—Ortho states this bag treats up to 33,000 sq ft—so it suits routine seasonal treatments on medium to large yards. Key practical benefits are simple application with a compatible spreader, quick knockdown of active insects, and multi-month protection that reduces how often you need to re-treat. Limitations to note are the granule format requires even spreading and immediate watering, performance varies by pest (some ants and fire ants are excluded) and it does not replace targeted grub-specific or professional treatments for heavy infestations.
Best for: Buyers who want an efficient, low-effort seasonal solution to reduce common lawn pests across large yards and minimize repeat treatments.
Less Ideal for: Homeowners needing a liquid or spot-treatment solution, those with small container or indoor gardens, or properties with severe, specialized infestations that need professional or targeted grub control.
- Fast contact kill for many listed lawn pests
- Long residual control up to 6 months for most ants and about 3 months for other insects
- Large coverage suitable for medium to very large yards
- Easy to apply using a standard broadcast spreader and water-in activation
- Does not control all ant species and excludes fire ants for fast action
- Granule format requires precise spreading and immediate watering to activate
Verdict: A practical, large-area granular treatment that quickly reduces common lawn pests and provides multi-month protection so you can treat less often.
Choosing the Right Grub Killer for St. Augustine Grass: Key Factors to Consider
Active Ingredient and Mode of Action
Knowing the active ingredient is the first step in choosing a grub killer. Different actives target grubs at different life stages and have varying onset speeds. Some ingredients kill larvae quickly after ingestion or contact, while others act more slowly but provide longer residual protection. Understanding mode of action helps you match treatment timing to grub life cycles and reduces the chance of repeated applications.
Active chemistry also ties directly to safety for St. Augustine grass and beneficial soil organisms. Certain ingredients are formulated with turf-safe carriers or in granular forms that minimize foliar exposure, which matters when treating established turf. Always check label directions to confirm the active is labeled for use on St. Augustine lawns and follow any crop or turf-specific precautions.
Timing and Treatment Window
Grub control is largely about timing. Most white grubs are most vulnerable as newly hatched larvae in late spring and early summer, and again for some species in late summer and fall. Applying a grub killer during the active feeding window increases efficacy and can reduce turf damage.
For St. Augustine grass, plan treatments to avoid peak turf stress from heat or drought. Some products work preventatively and are applied before larvae hatch, while others are curative and require visible grub activity to be effective. Choose a product whose labeled timing matches the grub species in your region and your lawn maintenance calendar.
Turf Safety and Stress Considerations
St. Augustine grass can be sensitive to high temperatures, excessive fertilizer, and some chemical treatments. A grub killer that is labeled safe for St. Augustine and has low phytotoxicity reduces the risk of brown patches after application. Consider how application timing intersects with seasonal stressors such as summer heat or recent aeration.
Also account for any post-application restrictions like delayed mowing, irrigation requirements, or reentry intervals. Products that require heavy watering immediately after application may be harder to use during drought. Selecting a treatment with clear turf-safety guidance helps protect your lawn while addressing grub pressure.
Formulation and Application Method
Grub killers come in granular, liquid concentrate, and ready-to-use formulations. Granular products are often easier for homeowners to apply with a broadcast spreader and deliver localized soil contact. Liquids can be applied through a hose-end sprayer or pump sprayer for more uniform coverage but may require more precise mixing and calibration.
Think about how you like to work on your lawn. Granules are lower-mess and do not require immediate reentry after application, while liquids sometimes allow finer control of coverage and can soak in more quickly if irrigation follows. Application equipment compatibility, drift risk, and storage convenience are all practical concerns for routine lawn care.
Residual Activity and Reapplication Needs
Residual activity determines how long a product continues to protect turf from new grub infestations. Some treatments offer several weeks to months of residual control, which reduces the need for repeat treatments in a single season. Others provide a short window of control and may need follow-up applications.
Longer residuals are useful if your area has staggered grub hatch times, but they also increase exposure time for non-target soil organisms. Balance the convenience of residual protection with environmental considerations and label guidance about maximum annual application rates.
Watering Requirements and Environmental Safety
Many grub killers require irrigation after application to move the active ingredient into the root zone where grubs feed. The amount and timing of required watering vary by formulation. For St. Augustine grass, light but thorough watering helps the product reach larvae without overwatering turf and increasing disease risk.
Also consider runoff and local water protections. Avoid treating before heavy rain events that could wash product off the lawn. Products with clear, minimal irrigation requirements are easier to use responsibly in landscapes near waterways or storm drains.
When To Scout For Grubs In St. Augustine Lawns
Scout your lawn in late spring and late summer to catch grub activity early. Look for thinning turf, areas that pull up like a loose carpet, or birds and raccoons digging for insects. Dig a little soil plug around an affected area to check roots and look for C-shaped white larvae.
Regular monitoring helps you decide whether a curative treatment is needed or if preventive timing is a better fit. Scouting also reveals whether damage is recent grub feeding or another turf problem such as root rot, disease, or irrigation issues.
- Inspect high-traffic and low-traffic areas; grubs often appear in patches where soil has been undisturbed.
- Check 10 to 15 small plugs across the lawn for a representative sample.
- Note the size of larvae to estimate their life stage and match timing to product labels.
Preventive Versus Curative Strategies
Preventive applications are aimed at newly hatching larvae and are often applied in late spring or early summer depending on region. These treatments reduce the chance of visible turf damage but require accurate timing and may not be necessary every year.
Curative treatments are applied when grubs are already present and causing damage. These often act faster on visible larvae and are the better choice when scouting shows active feeding. Consider soil temperature and moisture because those factors influence grub activity and product uptake.
- Use preventive products if your lawn has a history of heavy grub pressure.
- Choose curative options if you find multiple active larvae and visible turf decline.
Safe Application Practices For Warm-Season Turf
Apply treatments during cooler parts of the day and follow label directions for temperature or humidity restrictions. Avoid applying during drought stress or when turf is already weakened from heat. When applying granular products, calibrate your spreader so coverage is even and avoid overlapping passes.
After application, follow recommended irrigation practices to move the active ingredient into the root zone without creating runoff. Keep pets and children off treated areas according to the product label and reentry instructions.
- Mow a few days before treatment rather than immediately after application.
- Keep application equipment clean and calibrated for even coverage.
- Store unused product in a cool, dry place away from pets and children.
Cultural Practices That Reduce Grub Pressure
Cultural care can lower the chance of severe grub outbreaks. Maintain deep, infrequent watering to encourage stronger roots and healthier turf that tolerates some feeding. Proper mowing height for St. Augustine grass helps shade soil and reduce egg-laying sites for some beetles.
Incorporate practices such as aeration to improve root development and reduce thatch, which can harbor insect eggs and larvae. Healthy lawns are less likely to suffer severe damage and often recover faster after treatment.
- Water early in the morning and avoid overwatering in late afternoon.
- Adjust mowing height to the recommended range for St. Augustine to support root depth.
- Use aeration on compacted soils to encourage deeper roots and better biological activity.
Integrating Biological Controls and Beneficials
Biological options such as nematodes can complement chemical grub control and are especially useful in localized infestations or organic-minded programs. Beneficial nematodes target soil-dwelling larvae and pose low risk to turf and non-target organisms but usually require moist soil and precise application for success.
Biologicals may act more slowly than chemical curatives and are sensitive to UV exposure and desiccation. Use them when soil conditions and timing align, and consider them as part of a rotational strategy to reduce reliance on a single active ingredient.
- Apply biologicals in the evening or on overcast days to protect them from sunlight.
- Keep soil moist before and after applying beneficials for best establishment.
- Combine biologicals with cultural care for longer-term grub management.
How We Chose the Best Grub Killer for St. Augustine Grass
We prioritized products and formulations that balance effective grub control with proven turf safety for St. Augustine grass. Our editorial filters focused on control timing, active ingredient profile, application flexibility, and labeled turf compatibility to ensure treatments match common grub species and seasonal emergence in warm-season lawns. Key evaluation criteria included the active ingredient and documented efficacy against common white grubs, the product's safety record and explicit labeling for St. Augustine turf, the effective treatment window and residual activity, and ease of application including spreader or sprayer compatibility. We also judged how rapidly visible grub mortality typically occurs and whether the product requires irrigation or specific mowing restrictions. We excluded products without clear turf-label guidance, formulations intended only for ornamental beds, and treatments that demand intensive equipment beyond household spreaders or sprayers. Products were compared on practical gardener concerns: how they fit into a maintenance calendar, risk to desirable turf and soil life, and how straightforward the application is for homeowners.
FAQ
How do I know if grubs are the cause of my St. Augustine lawn damage?
Look for irregular brown patches that lift easily from the soil, plus animal digging. Dig a small plug and inspect for C-shaped white larvae in the root zone. If you find multiple larvae per plug, grubs are likely the cause.
When is the best time to treat grubs in St. Augustine grass?
Treat in late spring or late summer depending on your region and the grub species. Preventive treatments are applied before hatching, while curative treatments are used once larvae are present and active.
Can I apply a grub killer when the lawn is stressed from heat?
It is best to avoid treatments during peak heat or drought stress. Apply when turf is actively growing and not overly stressed, and follow label guidance about post-application irrigation to reduce the risk of further damage.
Are biological controls effective on St. Augustine lawns?
Biologicals like beneficial nematodes can be effective for localized infestations and fit organic programs. They require moist soil, careful timing, and protection from sunlight, and they often act more slowly than chemical curatives.
How much watering is needed after applying a grub killer?
Watering needs vary by product. Many granular treatments require light irrigation to move the active ingredient into the root zone, while some liquid formulations suggest immediate watering. Always follow label instructions to avoid runoff.
Will treating for grubs harm earthworms and beneficial soil life?
Some broad-spectrum insecticides can affect non-target soil organisms if used repeatedly. Choosing products labeled for turf safety and using targeted applications limits non-target impacts. Integrating cultural practices and biologicals also reduces reliance on chemical treatments.
Final Verdict
For St. Augustine grass, prioritize treatments that balance effective grub knockdown with clear turf-safety labeling and sensible application requirements. Time treatments to grub life stages, use formulations that match your application equipment and maintenance routine, and avoid treating during peak turf stress. Consider biologicals and improved cultural practices to reduce future outbreaks. Ultimately, choose a product that fits your timing needs, watering capacity, and willingness to rotate control methods. Focus on protecting root health and following label directions to preserve your St. Augustine lawn while addressing grub pressure confidently.
