Is your lawn brown and patchy?
If so, the problem could be grubs.
Left untreated, a grub infestation can destroy your grass. Fortunately, you don’t have to live with these pests forever.
Here at Smith’s Pest Management, we provide grub control services to help San Francisco Bay Area homeowners deal with grubs.
This blog will share our top tips for getting rid of grubs in your vegetable garden, flower beds, outdoor potted plants, or yard. These treatment tips are also effective for fleas and chiggers in your yard.
Let’s dive in.
What are Grubs, and How do They Damage Lawns?
Grubs are the larval stages of different beetle species, including Japanese beetles, June beetles, and European chafers.
These pests have soft, white bodies with a set of legs near their heads. When disturbed, they curl into a C shape.
Dormant during the winter, grubs become active when the weather starts to warm up. During the spring and early summer, grubs eat the roots of grass and other foliage and organic matter, causing extensive plant damage.
As lawn grubs turn into adult beetles, they leave the soil to mate and lay eggs. Adult beetles have a 1–3-year lifecycle.
Adult beetles lay their eggs near their feeding sites in July and August, creating new grubs that dig into the soil and eat grass roots, perpetuating the infestation.
Fortunately, it is possible to control grubs with methods like milky spore disease, which we’ll discuss more later in this post.
6 Signs of Grub Damage in Your Lawn
Not sure whether you have grubs in your yard or not?
Here are a few sure-fire signs that will help you identify grub damage:
- Yellowing grass. As grubs consume the roots of turfgrass, the grass turns spongy and yellow. If you tug at it, it will roll back like a carpet.
- The presence of other pest species. Skunks, raccoons, and other digging pests love to eat grubs and will destroy your lawn searching for them. This damage can be as expensive and difficult to fix as grub damage itself.
- Increasing numbers of moths or beetles. If you’ve noticed many moths or beetles flying around at grass level, it could signify that you have a serious grub problem.
- The appearance of drought. If your yard looks drought-stricken, despite regular watering, the problem could be grubs. Grub damage often looks like drought, but additional watering won’t fix it.
- Brown, patchy grass. Before the grass begins to yellow and pull up, it will turn brown and patchy. This damage will appear in random spots around the lawn.
- The presence of white grubs. Use a spade to cut a square foot section of turf, about 2-4 inches deep. Pull back the square and inspect the soil below. If you see grubs, you’ve got an infestation–even if you haven’t noticed damage in your lawn.
It can be tough to identify what grub damage looks like, especially since it often resembles other types of damage, like drought.
However, keeping an eye out for these six signs can help you stop grub damage in its tracks.
How to Get Rid of Grubs in Your Yard Naturally: 7 Treatment Options
If you’ve got grubs in your yard, you’re probably wondering how to get rid of them naturally–without harsh pesticides.
Fortunately, you’ve got options.
Here are a few methods we recommend:
1. Introduce natural predators to eat the grubs
Grubs have plenty of natural predators. While predators like raccoons and moles will damage your yard, others won’t.
Birds like chickadees, blue jays, and robins, for example, love grubs and will happily eat them all day long. Backyard chickens will also graze the yard and pick up grubs.
To use birds as a natural control method for grubs, make your yard as attractive as possible for the winged visitors.
Add bird feeders, birdbaths, and birdhouses around your yard. This will attract beneficial bird species and help keep your yard’s grub populations in check.
Pros: Easy, non-toxic, safe for households with kids and pets.
Cons: Birds may damage vegetable gardens or potted plants.
2. Limit moisture
Grubs need moisture to survive and thrive. As such, one easy way to decrease their numbers is to create an artificial drought.
If your lawn can go dormant and recover once you start watering it again, stop irrigating your yard for a few weeks in July. This will kill eggs and young grubs and reduce the grub population.
Pros: Easy, non-toxic.
Cons: Going too long without water kills the lawn; this is only effective if your yard isn’t receiving water from natural sources like rain.
3. Use milky spore
Milky spore is a bacterial disease that targets the larval stage of Japanese beetles. An eco-friendly, non-toxic, natural option, milky spore is an excellent way to control white grub populations.
You can purchase milky spore at your local home and garden store and use an inexpensive milky spore dispenser to apply it to your yard.
For best results, you’ll need to apply milky spore a few times a year for about 2-3 years. Once the course of treatment is complete, the milky spore will act as a biological control for 15-20 years.
If you’re going to use milky spore successfully, you’ve got to pay careful attention to environmental conditions, including temperature, moisture, soil structure, pH, and soil type, since the spores are very sensitive.
Soil temperature is an especially crucial consideration, as the spores will take longer to develop in colder climates or during colder seasons. The ideal soil temperature for spore development is between 60° and 70 °F.
It’s also important to understand that milky spore only spreads when grubs are present in the soil. The more grubs, the faster the milky spore will get established.
Pros: Affordable, easy to apply.
Cons: The efficacy of milky spore disease is subject to variables including product variability, soil temperature and conditions, and grub resistance; it can take 2-3 years for spores to build up and become an effective pest control method; milky spore only kills Japanese beetle grubs.
4. Use neem oil or Azadirachtin
Azadirachtin is a component of neem oil. While many people think neem oil and Azadirachtin are the same things, neem oil contains very little Azadirachtin.
As such, people usually buy concentrated Azadirachtin to use on their lawns. According to one study, Azadirachtin application on Kentucky bluegrass killed Japanese beetles at 5x the product’s label rate.
Neem oil is another pest control option. Pure neem oil deters the grubs from feeding, growing, and laying eggs. For best results, mix neem oil with water (according to label directions) and spray the diluted solution on affected areas.
Pros: Both options are affordable; Azadirachtin is classified by the EPA as “relatively non-toxic” (which means it presents low toxicity to biocontrol agents, predators, and parasitoids), while neem oil is considered non-toxic, which means it won’t harm people or non-target organisms.
Cons: Both neem oil and Azadirachtin require regular reapplication; despite its efficacy at killing larval Japanese beetles, Azadirachtin won’t kill mature beetles or deter them from laying eggs.
5. Introduce beneficial nematodes
Nematodes are tiny parasitic worms that can be used to target and kill many garden pests, including grubs.
Commonly used alongside milky spore disease, beneficial nematodes are a safe, pet-friendly way to kill grubs. You can buy beneficial nematodes at your local home and garden center.
Once you’ve purchased them, apply the nematodes to your yard immediately (follow the application directions on the package the nematodes came in).
Apply them early in the morning or during the late afternoon and avoid placing them in areas of direct sun, which can make them less effective.
After applying the first batch, you’ll likely need to introduce a fresh crop of nematodes once or twice a year for about three years to establish the population.
Pros: Can be effective; long-term solution.
Cons: Ground controlling nematodes must be alive and shipped refrigerated; nematodes must be used immediately after opening the package; the application sprayer must be very clean and free of any other chemical residues from previous applications; if the lawn has been treated with insecticide in the last year there’s a very high likelihood that residual insecticide could harm or kill the nematodes; nematodes take a long time to get established.
6. Make a grub killer with borax
Borax is a common household cleaning ingredient that can be used to kill grubs.
However, it should be noted that borax contains boron, which builds up in the soil and can kill your lawn in high concentrations. With that in mind, use this method sparingly–if at all.
If you decide to use borax, add a tablespoon to a spray bottle filled with warm water. Apply the solution liberally anywhere you’ve noticed grub activity.
Pros: Effective for short-term use.
Cons: Borax grub killer can damage plants when used too frequently or in sensitive areas, like flowerbeds or vegetable gardens.
7. Dethatch and aerate your lawn
Dethatching and aeration make your lawn less attractive for grubs. Because thatch and dense, compacted soil provide a thick layer of shelter for grubs, removing thatch and aerating the lawn creates a less welcoming environment for the pests.
Additionally, these methods make it easier for milky spore disease, nematodes, and other natural solutions to penetrate the surface of the lawn and reach the grubs–killing them faster and more efficiently.
Pros: Safe, effective, good for the lawn.
Cons: Labor-intensive. Does not kill grubs.
2 Conventional Ways to Get Rid of Grubs
If you’re looking for a convenient way to get rid of grubs, you’re in luck.
There are two primary chemicals used to reduce lawn grub populations: carbaryl and trichlorfon.
Both effectively kill grubs and are generally considered the only options when high concentrations of grubs are found in the fall or early spring–before May.
Research indicates that these compounds will kill 20-80% of grubs when applied in September and 20-55% of grubs when applied in late October.
Here’s a breakdown of each:
Carbaryl is a short-lived carbamate compound that is effective at killing grubs. Current research suggests that carbaryl may be slightly more effective at killing certain species of grubs, like the European chafer grub, than trichlorfon.
Carbaryl begins to kill grubs 10-14 days after application. Unfortunately, research suggests that carbaryl is toxic to beneficial insects, honeybees, and other bees, so it must be used sparingly and only by professional pest management companies.
Trichlorfon is an organophosphate that starts killing grubs within about 1-3 days. The chemical breaks down after about 7-10 days. Like carbaryl, trichlorfon is most effective when applied in the early spring or fall.
What About Preventative Chemicals?
Both carbaryl and trichlorfon are insecticides used to reduce existing grub infestations. They work best, though, when combined with preventative treatments.
Products containing imidacloprid, thiamethoxam, or clothianidin, for example, will reduce 75-100% of lawn grubs when applied in June or July and watered with at least 0.5” of irrigation immediately after application.
How do Pest Control Experts Get Rid of Lawn Grubs?
Considering hiring our professional team to get rid of your lawn grubs?
Here’s what you can expect from our process:
1. Initial Evaluation
The first step of our grub treatment process is a comprehensive evaluation of your site. We’ll visit your property, look at the soil, dig up some of the bedding areas, and sift through the soil to confirm the presence of grubs and determine the species.
We also examine any other lawn damage caused by animals like raccoons or skunks, which can indicate the presence of grubs.
After we’ve determined the presence of the grubs, we’ll choose a treatment method. We may use beneficial nematodes and milky spore fungus or a liquid systemic insect product.
Regardless of which option we recommend, we’ll always make sure you’re getting the best treatment for lawn grubs for your needs.
We’ll ask that you stay off the lawn during the treatment and for a period after that to allow the product to sink into the soil.
We’ll run your irrigation system for about 20 minutes to expedite the process. After the lawn is dry, the area can be used as normal.
3. Follow-Up Treatment
Next, we’ll recommend follow-up treatments to kill grubs at different phases of their life cycles. We recommend annual touch-ups because Japanese beetle adults will come to lay eggs every year.
4 Lawn Grub FAQs
1. When is the best time to treat for grubs?
Grub control agents should be applied during early spring and late summer when your lawn shows signs of increased grub activity.
On the other hand, grub prevention agents should be applied during June-July–before the grubs hatch.
2. Will grass come back after grubs?
If the grubs have killed patches of grass, you’ll have to reseed the area to promote new growth.
We recommend watering it lightly, overseeding it with a quality turfgrass mixture, and keeping pets and kids off it until the grass is 2-3” tall.
3. How do I know if I have fungus or grubs?
Grub damage is most pronounced when the weather gets warm. Fungal damage, on the other hand, thrives when the temperature fluctuates.
Check for grubs or fungal damage by grabbing an area of damaged grass and pulling gently. If the roots are gone, it’s probably grub damage rather than a fungus.
4. Will grubs go away on their own or die in the winter?
Grubs hatch in late summer and begin to feed. They lay eggs that hatch and grow until mid-fall, at which point the grubs move deeper into the soil to survive the chilly winter season.
Are Grubs Taking Over Your San Francisco Bay Area Yard? We’re Here to Help!
Grubs can do severe damage to your yard. Fortunately, you don’t have to accept those brown, dead patches any longer.
Here at Smith’s Pest Management, our team knows how to get rid of grubs in Bay Area yards, gardens, and flower beds.
Using traditional and eco-friendly techniques, we’ll solve your grub problem and restore your beautiful, green yard.
Contact us today to schedule your pest control inspection or to request a free quote.