Are Lawn Grubs Destroying Your Lawn?
You water. You mow. You fertilize. And yet, ugly brown patches start spreading across your lawn—and when you tug at the grass, it lifts like a welcome mat. If this sounds familiar, you may be dealing with grubs.
Lawn grubs, also known as white grubs, are the underground larvae of beetles like June bugs, Japanese beetles, and chafer beetles. These C-shaped pests feed on your lawn’s root system, silently damaging it from below. The result? Grass that can’t absorb water or nutrients, leading to wilting, dead patches, and costly repairs.
In South Florida’s warm, humid climate, these pests thrive nearly year-round. Knowing how to identify them—and when to treat them—can save your lawn before the damage becomes widespread.
Signs You Might Have a Grub Problem…
Before diving into treatments, it’s important to confirm whether grubs are the culprit. Look for these common signs:
Brown or Wilting Patches
Dead or thinning areas of grass that don’t improve with watering can indicate root damage caused by feeding grubs.
Spongy or Loose Turf
When the root system is destroyed, grass becomes easy to lift and may feel soft underfoot—almost like a new piece of sod.
Increased Animal Activity
Birds, raccoons, armadillos, and other wildlife often dig up lawns to feed on grubs beneath the surface.
Beetle Activity in Summer
Large numbers of beetles flying or crawling around your yard in June or July can be a warning sign that eggs are being laid in your lawn.
Grubs Visible in the Soil
The most definitive test is to dig up a square foot of turf, 2–4 inches deep, in an affected area. Finding more than five white, C-shaped grubs indicates a moderate to severe infestation.
Understanding the Grub Life Cycle (and Why It Matters)
Grubs follow a predictable life cycle. Timing your treatment around their most vulnerable stage—when they’re young and near the surface—makes your efforts more effective.
Here’s what the life cycle looks like in South Florida:
| Stage | Timeframe | What’s Happening |
|---|---|---|
| 🪲 Eggs | June–July | Adult beetles lay eggs in lawn soil |
| 🐛 Larvae (Grubs) | August–October | Eggs hatch into hungry grubs that feed aggressively on grass roots |
| 🪱 Pupae | Late Fall–Winter | Grubs go dormant deeper in the soil while developing into adult beetles |
| 🪲 Adults | Spring | Beetles emerge, ready to mate and restart the cycle |
Because South Florida’s climate is mild, grubs may remain active later into the year compared to other regions. That means fall is your best opportunity to intervene before damage becomes severe.
When to Treat for Grubs in South Florida
To protect your lawn, target grubs when they are young and actively feeding near the surface. Here’s a general seasonal guide:
| Timeframe | What’s Happening | What You Should Do |
|---|---|---|
| Late July – Early August | Beetles lay eggs in your lawn | Monitor beetle activity, prepare for treatment |
| August – September | Eggs hatch into grubs; active root feeding begins | Apply grub control treatments |
| October – Winter | Grubs move deeper and slow down | Focus on lawn repair and future prevention |
Preventive vs. Curative Grub Treatments
There are two main types of grub treatment options, each with a specific purpose and timing.
Preventive Grub Treatments
- Best Time to Apply: Late spring to early summer (before grubs hatch)
- How They Work: These products stay active in the soil and kill grubs as they hatch
- Common Ingredients:
- Chlorantraniliprole (e.g., Scotts GrubEx)
- Imidacloprid
Preventive treatments are ideal if you’ve had grub issues in the past or want to protect newly installed sod from damage.
Curative Grub Treatments
- Best Time to Apply: August through early October (when grubs are feeding)
- How They Work: These products kill existing grubs quickly
- Common Ingredients:
- Trichlorfon (e.g., Bayer 24-Hour Grub Killer Plus)
- Carbaryl
Curative options are best when you’ve confirmed an active infestation or see signs of root damage.
How to Apply Grub Control Properly
For maximum effectiveness, follow these application steps:
- Read the Label
Always follow the product instructions, including safety precautions and dosage. - Water Before Application
Moistening the soil beforehand helps products penetrate more effectively. - Apply Evenly
Use a spreader for granular products or a hose-end sprayer for liquid treatments to ensure even coverage. - Water After Application
Lightly water your lawn after applying the treatment to activate the ingredients and move them into the soil. - Keep Off the Lawn Temporarily
Avoid letting pets or children onto the treated lawn until it has dried and absorbed into the soil, usually within 24 hours.
Monitoring and Preventing Future Grub Damage
Even after treatment, continued vigilance will help keep your lawn healthy.
Conduct Regular Inspections
Check for signs of grub activity at the end of each summer. If you’re unsure, dig a small section of turf to investigate.
Maintain a Healthy Lawn
Healthy lawns tolerate grub damage better. Mow at the correct height, water deeply but infrequently, and follow a balanced fertilization schedule.
Aerate and Dethatch
Aerating annually reduces soil compaction and makes the lawn less attractive for beetles to lay eggs. Removing thatch also helps expose grubs to natural predators.
Watch for Beetle Activity
If you see large numbers of beetles in early summer, there’s a strong chance of grubs later in the season. That’s the time to consider preventive treatment.
When to Call a Professional Grub Control Service
If your lawn is showing widespread damage—large brown patches, peeling turf, or signs of multiple infestations—DIY solutions may not be enough.
Professional lawn care experts have access to commercial-grade products, soil testing tools, and customized treatment plans. They can also help you identify other issues that may be contributing to your lawn’s decline, such as fungal disease or poor drainage.
Let Floridist Restore Your Lawn
At Floridist, we specialize in science-backed lawn renovation and pest management. If grubs are taking over your lawn, we can help you stop the damage at the root and rebuild a lush, resilient yard.
Give us a call or text at 561-941-GROW to schedule a grub inspection or treatment. Let’s keep your lawn healthy and green—without the guesswork.