How do you kill worms in the yard without harming grass? The short answer is that you first need to figure out if the “worms” are actually pests like grubs or cutworms, and then use methods that target those specific pests while keeping your grass healthy. Not all worms in your yard are bad; earthworms are good for the soil. When dealing with harmful insects that look like worms, like grubs or cutworms, you can use natural steps or carefully chosen bug killers (insecticide for lawn) applied at the right time. Keeping your grass strong with good care is also a big help in preventing lawn worms and other lawn damaging insects.
Let’s look closer at how to handle those unwanted lawn pests.
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Not All Worms Are Bad Guys
Before you try to get rid of any worms in your yard, it’s super important to know what kind you have. Many people see any squirming thing in the dirt and think it’s a problem. But some “worms” are actually helpers! This is the first step in lawn worm identification.
Earthworms Help Your Lawn
Earthworms are the heroes of your soil. They are long, often reddish-brown worms you might see after rain. They tunnel through the soil, which does amazing things for your grass:
- They loosen hard dirt. This lets air and water get down to grass roots easily.
- They eat dead leaves and grass. This breaks down old stuff and makes the soil richer.
- They leave behind worm castings (their poop). This is like free fertilizer for your grass.
Trying to kill earthworms would actually hurt your lawn in the long run. They are a sign of healthy soil. When people talk about killing worms in the yard because their grass looks bad, they usually mean a different kind of pest.
Who Are the Bad Guys?
The “worms” that cause damage to lawns are usually not true earthworms. They are most often the young forms (larvae) of certain insects. The two most common troublemakers are grubs and cutworms. These are common lawn damaging insects that fall under the umbrella of turf insect management.
- Grubs: These are probably the most common “lawn worm” pest. They are the larvae of beetles like the Japanese beetle, June bug, or European chafer. Grubs are white, C-shaped, with brown heads, and have six legs near their heads. They live in the soil and chew on grass roots.
- Cutworms: These are the larvae of certain moths. They are caterpillars, usually brown or gray, that curl up in a C-shape when you touch them. They live just above or below the soil surface and chew on grass blades or stems at the base, often cutting them right off.
Dealing with grubs (grub control lawn) is different from dealing with cutworms. Identifying which pest you have is key to picking the right way to kill them without hurting your grass or beneficial earthworms.
See If You Have Pest Worms
How can you tell if grubs or cutworms are the reason your grass looks sad? They leave clues. Recognizing these signs is part of effective lawn pest control.
Look at Your Grass
Pest worms cause specific kinds of damage:
- Dead Patches: Grubs eat the roots. When roots are gone, the grass can’t get water and turns brown and dies in patches. These patches might start small but can grow.
- Spongy Feel: If you walk on the brown patches caused by grubs, the ground might feel soft and spongy because the grass isn’t anchored by roots anymore.
- Grass Pulls Up Easily: A sure sign of grubs is being able to lift patches of dead or dying grass easily, like lifting a piece of carpet. There will be very few roots holding it down. You might see the grubs wiggling underneath.
- Chewed Blades: Cutworms chew grass blades, often near the soil line. You might see blades that look like they’ve been cut unevenly or look shorter in spots. This damage often shows up overnight.
- Animal Digging: Birds, raccoons, skunks, and other animals love to eat grubs. If you see your lawn being dug up, especially in patches, animals are likely looking for grubs. This is a big sign you have a grub problem.
Dig a Little Bit
To know for sure what’s going on, you can do a simple check:
- Pick a spot where your grass looks damaged or where you suspect pests.
- Use a shovel or trowel to cut a square piece of turf about 6 inches on each side and about 2-4 inches deep.
- Carefully lift the grass piece and turn it over.
- Look through the soil and roots for grubs (white C-shapes) or cutworms (brown/gray caterpillars).
- Count how many pests you find in that 6×6 inch square.
Finding just one or two grubs or cutworms is usually not a big deal. A healthy lawn can handle a few. But if you find 5-10 or more grubs per square foot (roughly two 6×6 squares), that’s a sign of a problem that could cause serious damage and might need treatment. For cutworms, seeing a few can be enough to cause visible damage, especially to shorter grass. This simple test helps you confirm your lawn worm identification.
Why These Pests Are a Problem
Grubs and cutworms aren’t just unpleasant to look at. They actively harm your lawn, which is why people seek solutions for killing grubs in lawn and other treatments.
They Eat Grass Roots
Grubs are the primary root-eaters. They live in the soil and feed on the root system of your grass. This prevents the grass from taking up water and nutrients. As the roots disappear, the grass weakens, turns yellow or brown, and eventually dies. Severe grub infestations can kill large areas of your lawn, requiring expensive repair or replacement. The damage is often worst in late summer and early fall when grubs are large and hungry.
They Chew Grass Blades
Cutworms, on the other hand, usually feed on the upper part of the grass. They hide in the soil during the day and come out at night to feed. They often chew through grass blades or young stems right near the soil surface. This can make the grass look uneven or patchy, like someone gave it a bad haircut. In severe cases, they can cause significant thinning of the lawn.
These pests are definite lawn damaging insects, and dealing with them is a necessary part of lawn pest control if you want healthy, green grass.
When to Deal With Pest Worms
Timing is everything when it comes to effective lawn treatment for pests, especially grubs and cutworms. Applying treatments at the wrong time wastes your effort and money and can hurt good bugs.
Grub Time
The best time for grub control lawn efforts depends on the type of product you use:
- Preventative Treatments: These stop grub eggs from hatching or kill very young grubs. They are the most effective way to prevent grub damage. You need to apply these before the eggs hatch, usually in late spring or early summer (often May, June, or early July), depending on your location and the specific beetle. The product label will give the best timing.
- Curative Treatments: These kill larger, actively feeding grubs. They are used when you already see signs of grub damage in late summer or early fall. These work best in late summer or early fall (August to October) when grubs are big but still near the surface and actively eating. As the weather gets cold, grubs move deeper into the soil and are harder to reach with treatments. Treating in spring for last year’s grubs is usually not very effective as they are turning into beetles or are deep in the soil.
So, for grub control, think early summer for prevention and late summer/early fall for fixing a problem.
Cutworm Time
Cutworms are typically a problem in the spring and early summer when they are young caterpillars. They can also be an issue in the fall in some areas. You’ll usually see damage fairly soon after they start feeding. Treat when you first notice cutworm activity or damage.
Timing your lawn treatment for pests correctly means you use less product and get better results. It also reduces the risk to beneficial insects and earthworms who might not be active at that specific time.
Use Nature to Fight Pests
Killing grubs in lawn and other pests doesn’t always mean reaching for strong chemicals. Many natural lawn pest control methods can be very effective and are better for the environment, pets, and beneficial insects. These methods are a great way to prevent lawn worms by creating an unhealthy place for pests to live.
Healthy Lawn, Fewer Pests
A strong, healthy lawn is much better at fighting off pests and recovering from damage than a weak one. This is a key part of preventing lawn worms through good turf insect management.
Water Right
Deep, less frequent watering is better than shallow, frequent watering.
* How: Water long enough for moisture to go down 4-6 inches into the soil. Check by sticking a screwdriver or probe into the ground after watering.
* Why it helps: This encourages grass roots to grow deeper, making the plant stronger. It also makes the top inch or two of soil drier between waterings, which is less inviting for beetles to lay eggs and can dry out young grubs or cutworms.
Cut Right
Proper mowing height makes a big difference.
* How: Mow your grass at a taller height, usually 3-4 inches depending on the type of grass. Don’t cut off more than one-third of the grass blade at a time.
* Why it helps: Taller grass blades create shade for the soil, keeping it cooler and holding moisture better (deeper down). This again encourages deep roots and makes the environment less favorable for many pests. It also provides habitat for beneficial insects.
Feed Right
Feeding your lawn helps it grow strong roots and bounce back from stress or damage.
* How: Use a balanced fertilizer based on a soil test. Fertilize at the right times for your grass type (often spring and fall).
* Why it helps: Healthy, well-fed grass is simply more able to tolerate some root feeding or blade chewing without dying. It can regrow faster.
Good Bugs and Tiny Critters (Nematodes)
Beneficial nematodes are microscopic worms (different from earthworms!) that live in the soil. Certain types of nematodes are natural enemies of grubs and cutworms. They hunt down the pest larvae in the soil and kill them.
- How they work: You buy them in a package (usually a powder or sponge). You mix them with water and apply them to your lawn using a sprayer or watering can. Once in the soil, they actively search for pests.
- When to use: Apply grub-killing nematodes in late summer or early fall when grubs are present. Apply cutworm-killing nematodes when you see cutworm activity.
- Tips for success:
- Buy from a good source and use them soon after you get them (they are alive!).
- Apply in the early morning or late evening when it’s cooler and less sunny. UV light can harm them.
- Water the lawn before applying nematodes so they can move easily through moist soil.
- Water again lightly after applying to wash them off grass blades and into the soil.
- Keep the soil moist for about a week after applying.
Nematodes are a great natural lawn pest control method because they only target certain insects and don’t harm earthworms, pets, or people. They are a core part of killing grubs in lawn naturally.
Milky Spore Powder
Milky Spore is a natural bacterium ( Paenibacillus popilliae) that specifically kills the grubs of Japanese beetles. It’s a slower method but can offer long-term control.
- How it works: Grubs eat the bacteria in the soil. The bacteria multiplies inside the grub, killing it. The dead grub releases more bacteria into the soil, which can then infect more grubs.
- When to use: It can be applied any time the ground is not frozen, but applying it when grubs are actively feeding (late summer/early fall) can help spread it faster.
- Tips for success:
- It only works on Japanese beetle grubs. If you have other grub types, it won’t work.
- It takes time (months or even a few years) to build up enough in the soil to provide widespread control.
- It’s very safe for everything else – earthworms, pets, people, other insects.
Milky Spore is a good option if Japanese beetles are your main grub problem and you are patient. It’s a form of biological lawn treatment for pests.
When You Need More Help
Sometimes, natural methods aren’t enough, especially if you have a very bad infestation or widespread damage already happening. In these cases, you might consider using an insecticide for lawn pests. Using these products safely and correctly is vital for successful lawn pest control without harming your grass or the environment.
What Are Lawn Pest Treatments?
Insecticides for lawns are chemicals designed to kill insects. They come in different forms, like granules you spread or liquids you spray. They work in different ways, depending on the active ingredient.
How They Work
- Contact Killers: Some insecticides kill insects when the pest comes into direct contact with the treated surface (like grass blades or soil).
- Systemic Killers: Some are taken up by the grass roots and move into the plant. When pests eat the treated grass or roots, they are poisoned.
- Ingestible Killers: Some products must be eaten by the pest to work (like grub baits or some granular products).
Picking the Right One
This is crucial for effective and safe lawn treatment for pests.
- Preventative vs. Curative:
- Preventative: These contain active ingredients like imidacloprid, clothianidin, or chlorantraniliprole. They are applied earlier in the season (late spring/early summer) to kill grubs shortly after they hatch or prevent them from developing. These are very effective at preventing grub damage but won’t do much against large grubs causing damage now. They often last a long time in the soil.
- Curative: These contain active ingredients like trichlorfon or carbaryl. They are faster-acting and designed to kill larger, actively feeding grubs in late summer or fall when you see damage. They don’t last as long in the soil as preventatives.
- For cutworms, look for products specifically labeled for cutworms. Active ingredients like permethrin or carbaryl are often used. Apply in the evening when cutworms are active.
- Read the Label: Always read the product label carefully before buying and before applying. The label is the law! It tells you:
- What pests the product kills (Does it kill grubs? Cutworms? Both?).
- The active ingredient.
- When to apply it (timing is key!).
- How much to use.
- How to apply it (granules or liquid).
- Safety precautions (wear gloves? stay off lawn?).
- If it needs watering in after application.
- How long pets and people need to stay off the treated area.
Put it Down Safely
Applying insecticides correctly protects your lawn, yourself, pets, and the environment.
- Calibrate Your Spreader/Sprayer: Make sure you are applying the correct amount of product per square foot or acre, as directed by the label. Too little might not work; too much can hurt the grass or run off.
- Timing of Day: Apply granular products when the grass is dry, and then water them in as directed. Apply liquid sprays usually when the grass is dry, often in the late afternoon or evening when temperatures are cooler and beneficial insects like bees are less active.
- Weather: Don’t apply if heavy rain is expected soon, as it can wash the product away. Avoid applying on windy days, especially sprays, to prevent drift.
- Water In: Many granular and some liquid grub treatments need to be watered into the soil right after application to reach the grubs where they live and eat roots. Check the label!
- Keep Off: Follow the label’s instructions on how long pets and people need to stay off the treated area. This can range from a few hours until dry to 24 hours.
- Protect Water: Never apply near water bodies, storm drains, or on hard surfaces where the product can wash into streams or lakes.
Using insecticides is part of turf insect management. When done right, it can effectively deal with pest problems. When done wrong, it can cause more harm than good.
What to Know About Grubs
Grubs are a major target for lawn pest control and killing grubs in lawn is a common goal for many homeowners. Let’s look closer at these lawn damaging insects.
Their Life Story
Most lawn-damaging grubs have a one-year life cycle:
- Summer (June-July): Adult beetles (like Japanese beetles) fly around, feed on plants, and lay eggs in the grass, usually in moist, healthy soil.
- Late Summer/Early Fall (August-October): Eggs hatch into tiny grubs. They immediately start feeding on grass roots. They grow quickly. This is when preventative treatments are most effective (before they get big) or when curative treatments target them.
- Late Fall/Winter (November-February): Grubs burrow deeper into the soil to survive the cold. They stop feeding. Treatments applied now won’t work well.
- Spring (March-May): Grubs move back up towards the surface as the soil warms and start feeding on roots again, but usually less heavily than in the fall. They then change into pupae. Treating in spring for large grubs is less effective than fall.
- Late Spring/Early Summer (May-June): Pupae turn into adult beetles, which crawl out of the ground, and the cycle starts again.
How They Hurt Grass
As mentioned, grubs eat the roots. This root feeding disconnects the grass from the soil, causing brown patches that pull up easily. The damage is often worst in late summer and fall because the grubs are larger and eating more. Dry conditions can make the damage look worse because the weakened grass can’t handle the lack of water.
How to Get Rid of Them
Grub control lawn efforts need to align with their life cycle.
Natural Ways
- Beneficial Nematodes: Apply Heterorhabditis bacteriophora nematodes in late summer/early fall when grubs are feeding. Water well before and after applying.
- Milky Spore: If Japanese beetles are the problem, apply Milky Spore powder. It takes time to work but offers long-term control.
- Healthy Lawn: Good watering, mowing, and feeding make your lawn strong and less likely to have severe grub problems. Preventing lawn worms this way is the first line of defense.
Chemical Ways
- Preventative Insecticides: Apply products with imidacloprid, clothianidin, or chlorantraniliprole in late spring or early summer (June/July) to kill newly hatched grubs. Read the label for exact timing and how much water to use after application.
- Curative Insecticides: If you have active damage from large grubs in late summer or fall (August/September), use products with trichlorfon or carbaryl. Water these in right after applying. These work faster on bigger grubs.
Choosing the right method and applying it at the right time is key to killing grubs in lawn effectively without harming your grass or good bugs.
What to Know About Cutworms
Cutworms are another common “worm-like” pest that can damage your lawn. They are also considered lawn damaging insects.
Their Life Story
Cutworm life cycles vary depending on the species, but many have one or two generations per year.
- Spring/Early Summer: Moths lay eggs on grass blades or other plants.
- Late Spring/Summer: Eggs hatch into caterpillars (cutworms). They feed on grass blades and stems, mostly at night. They hide in the soil or thatch during the day. This is when you usually see damage.
- Late Summer/Fall: Caterpillars finish feeding, burrow into the soil, and turn into pupae. Some species might have another generation of caterpillars.
- Winter: Pupae or sometimes adults or even larvae (depending on species and climate) overwinter in the soil.
- Spring: Adults emerge to start the cycle again.
How They Hurt Grass
Cutworms chew through grass blades or stems near the base. This can look like small, unevenly mowed patches or thinning areas. Because they feed at night, you might not see the pest, only the damage the next morning. Their feeding activity is part of why lawn treatment for pests might be needed.
How to Get Rid of Them
Managing cutworms is part of overall turf insect management.
- Find Them: If you suspect cutworms, you can check at night with a flashlight. You might see them feeding. You can also use a soap flush: Mix 1-2 tablespoons of dish soap in a gallon of water and pour it over a small area of suspected damage (about 1-2 sq ft). The cutworms should come to the surface within a few minutes.
- Natural Ways:
- Beneficial Nematodes: Some types of nematodes (like Steinernema carpocapsae) can help control cutworms. Apply them when cutworms are active and the soil is moist.
- Bacillus thuringiensis (Bt): This is a natural bacterium that kills certain caterpillars when they eat it. Look for products with Bt specific for turf caterpillars. Apply in the evening when cutworms feed. It’s safe for other animals and beneficial insects once dry.
- Healthy Lawn: A dense, healthy lawn can tolerate some cutworm feeding better and may recover faster.
- Chemical Ways:
- Look for insecticides labeled for cutworms. Active ingredients like permethrin, bifenthrin, or carbaryl are often used.
- Apply these treatments in the late afternoon or evening because cutworms feed at night.
- Avoid mowing for a day or two after application to let the product stay on the grass blades where cutworms will eat it.
- Follow all label instructions carefully.
Effective cutworm control relies on identifying the problem early and applying treatments when the pests are actively feeding.
Keep Everyone Safe
Using any method for lawn pest control, whether natural or chemical, requires thinking about safety. You want to kill the pest worms, not harm helpful creatures, pets, or people. This is a key part of responsible turf insect management.
Protect Good Bugs
Many insects in your yard are beneficial. Ladybugs eat aphids, some wasps attack pests, and bees pollinate plants. Earthworms are vital for soil health.
- Timing: Apply insecticides when beneficial insects are least active. For many, this is late afternoon or evening. Avoid applying during the peak flowering time of plants next to the lawn where bees might be.
- Targeted Products: Natural methods like nematodes or Milky Spore are highly targeted. Bt only affects caterpillars. These are safer for non-target insects.
- Spot Treat: If possible, only treat the areas where you see pests or damage, rather than your entire lawn.
- Read Labels: Labels often have information about toxicity to bees, fish, or other wildlife.
Protect Pets and People
Your family and pets use the lawn. Make sure they are safe after a lawn treatment for pests.
- Follow Re-entry Times: The product label will tell you how long you need to stay off the treated area. This might be until spray is dry, or a set number of hours (e.g., 12 or 24 hours). Follow this strictly.
- Store Products Safely: Keep all pest control products locked away, out of reach of children and pets.
- Wear Protective Gear: Wear gloves, long pants, and closed-toe shoes when mixing and applying pesticides.
- Clean Up: Wash your application equipment thoroughly after use. Wash your hands and clothes.
Care for the Earth
Pesticides can move off your lawn and into water systems or harm non-target animals.
- Avoid Runoff: Don’t apply before heavy rain. Avoid spraying or spreading onto sidewalks, driveways, or streets where products can wash into storm drains.
- Don’t Overuse: Only use the amount of product needed, as directed by the label. More is not better and can cause harm.
- Consider Alternatives: Always consider natural or cultural methods first as part of preventing lawn worms. Use chemicals only when necessary.
Safe use of any insecticide for lawn pests is just as important as choosing the right product and timing.
Stop Pests From Coming Back
Dealing with a pest problem once is great, but preventing lawn worms from becoming a major issue again is even better. Ongoing care is key to turf insect management.
Keep Your Lawn Strong
This goes back to the healthy lawn practices we talked about:
- Watering: Deep, less frequent watering promotes strong, deep roots that can better handle a little pest feeding and recover faster.
- Mowing: Keeping grass taller shades the soil, which can deter some pests and encourages healthier root growth.
- Fertilizing: Properly feeding your lawn keeps it thick and able to outcompete weeds and recover from minor pest damage. A thick lawn is less inviting for egg-laying pests.
- Aeration: Loosening compacted soil helps roots grow better and improves air and water flow, leading to healthier grass.
- Dethatching: Removing excess thatch (the layer of dead grass between green blades and soil) can reduce hiding places for some pests and improve water/nutrient movement.
These simple steps are powerful tools in natural lawn pest control and preventing lawn worms.
Watch Your Lawn
Regularly walking around your yard and looking closely at your grass helps you spot problems early. Early detection means you can often deal with a small issue before it becomes a big, damaging infestation.
- Look for early signs of brown patches or chewed grass blades.
- Watch for increased bird or animal digging.
- Check edges of pavement or garden beds where some pests like to hide.
- Knowing the life cycles of common lawn damaging insects in your area helps you know when to be most watchful (e.g., late summer for grub damage, spring/summer for cutworm damage).
Being observant is a simple yet effective part of lawn pest control and overall lawn treatment for pests.
Summing It Up
Dealing with “worms” in your yard is usually about identifying and controlling specific lawn damaging insects like grubs and cutworms, while protecting the good earthworms.
First, confirm you have pest worms by looking for signs like dead patches, spongy turf, or animal digging, and digging a small plug of grass to find them. Proper lawn worm identification is step one.
Next, decide on your approach. Natural lawn pest control methods like beneficial nematodes, Milky Spore, and maintaining a healthy lawn are great for preventing lawn worms and managing smaller problems. Healthy lawn practices like correct watering, mowing, and feeding build strong grass that resists damage and recovers better.
If you have a severe infestation or widespread damage, you might need to use an insecticide for lawn pests. Choosing the right product (preventative or curative) and applying it at the correct time of year is crucial for success, especially for grub control lawn efforts. Always read and follow label instructions exactly for application rates, timing, watering in, and safety precautions for people, pets, and beneficial insects.
Killing grubs in lawn and controlling other pests is an ongoing part of turf insect management and overall lawn treatment for pests. By understanding the pests, choosing the right methods, timing your treatments correctly, and keeping your grass healthy, you can protect your lawn and enjoy green, pest-free grass without causing unnecessary harm.
Common Questions About Lawn Pests
Q: Can earthworms hurt my grass?
A: No, earthworms are good for your grass! They help the soil by making tunnels, bringing air and water to roots, and breaking down dead stuff. They are not the pests that cause dead patches.
Q: When is the best time to treat for grubs?
A: For preventing grub damage, the best time is usually late spring to early summer (June/July) with a preventative product. If you already see damage from large grubs, the best time for a curative treatment is late summer to early fall (August/September).
Q: Are natural ways better than chemicals?
A: Natural methods like nematodes or Milky Spore are often safer for the environment, beneficial bugs, and pets. They can be very effective, especially for prevention or small problems. Chemical treatments can be faster-acting and might be needed for severe infestations. The “best” method depends on the situation, your goals, and your comfort level.
Q: Will rain wash away treatments?
A: It depends on the product. Granular products often need to be watered in to work, so light rain can be helpful. However, heavy rain shortly after applying some products can wash them away before they get into the soil or dry on the grass. Always check the product label for specific instructions about watering and rain.
Q: How do I know what pest I have?
A: Look at the type of damage (patches that pull up vs. chewed blades) and dig a small spot to see if you find grubs (white C-shapes) or cutworms (brown/gray caterpillars). Looking up pictures online based on the damage signs can also help with lawn worm identification.