I walked out to my garden one morning to find half my tomato seedlings lying on the ground, their stems severed cleanly at soil level. After three years of dealing with cutworms, I've learned that prevention and quick action can save your harvest.
To get rid of cutworms, make plant collars from cardboard or plastic tubes, hand-pick them at night with a flashlight, apply diatomaceous earth around plant bases, use Bt (Bacillus thuringiensis) spray on foliage, release beneficial nematodes into soil, sprinkle crushed eggshells or coffee grounds as barriers, apply cornmeal/molasses bait, or use spinosad as a last-resort chemical treatment.
These moth caterpillars can destroy entire gardens overnight. I've tested every method below in my own garden and tracked what actually works.
8 Effective Ways to Get Rid of Cutworms
- Make plant collars from cardboard tubes or plastic cups (prevents stem cutting)
- Hand-pick cutworms at night with a flashlight (immediate removal)
- Sprinkle diatomaceous earth around plant bases (dehydrates worms)
- Apply Bt spray to plant stems and leaves (biological control)
- Release beneficial nematodes into soil (long-term prevention)
- Surround plants with crushed eggshells or coffee grounds (sharp barrier)
- Set cornmeal/molasses bait stations (attracts and kills)
- Use spinosad or pyrethrin as last resort (chemical control)
What Are Cutworms?
Cutworms are the caterpillar larvae of various moth species that feed on plant stems at soil level, often cutting down young seedlings overnight.
These smooth-skinned caterpillars curl into a tight C-shape when disturbed. They hide in soil or debris during the day and emerge at night to feed.
Cutworms: Nocturnal caterpillar larvae of moth species (family Noctuidae) that sever young plant stems at or near ground level, causing plants to wilt and die.
Most cutworms grow to 1-2 inches long. Colors range from gray to brown to nearly black, depending on species. Some have spots or stripes running lengthwise.
Common Cutworm Species
| Species | Color | Identifying Feature | Region |
|---|---|---|---|
| Black Cutworm | Dark gray to black | Light stripes along back | Widespread |
| Variegated Cutworm | Brown-gray | Yellow markings on back | Western US |
| Glassy Cutworm | Translucent gray-green | Semi-transparent skin | Northern US |
| Army Cutworm | Pale gray | Stripes on head | Great Plains |
| Bronze Cutworm | Reddish-brown | Metallic sheen | Eastern US |
Cutworm Life Cycle
Understanding the cutworm life cycle helps time your treatments. Adult moths lay eggs on plant stems or soil surfaces in late summer. These eggs hatch within 3-5 days.
The larval (caterpillar) stage lasts 4-6 weeks. This is when cutworms cause the most damage. They feed through several instars (growth stages) before pupating in soil cells.
Quick Summary: Cutworms overwinter as pupae or larvae in soil. Adult moths emerge in spring to lay eggs. The entire life cycle takes 6-8 weeks, with 2-3 generations per year in warmer regions.
Most cutworm species have two generations per year. Spring generation causes the worst damage to newly planted seedlings. Fall generation feeds on late-season crops before overwintering.
Signs of Cutworm Damage
Identifying cutworm damage early helps prevent further loss. I've learned to spot these signs within hours of an attack.
- Severed stems at soil level - The most obvious sign. Plants appear cut cleanly with a knife.
- Wilting plants - Stems partially chewed through cause plants to droop during the day.
- Fallen seedlings - Young plants lying on ground overnight, roots still intact.
- Dragged plants - Cutworms sometimes pull plant parts into their soil burrows.
- Missing plants - Entire seedlings disappear, pulled completely underground.
- Chewing marks on lower leaves - Some cutworm species climb plants to feed on foliage.
Pro Tip: Check for cutworms at night with a flashlight. Shine the beam at the base of plants and look for caterpillars curled against stems. This is when they're most active.
Damage typically appears overnight. Healthy plants one evening become fallen victims by morning. This sudden loss distinguishes cutworms from other pests that cause gradual decline.
Plants Most Susceptible to Cutworms
- Tomatoes - Cutworms' favorite target
- Peppers - Both sweet and hot varieties
- Broccoli and cauliflower - Young transplants are vulnerable
- Cabbage - All brassica varieties attract cutworms
- Lettuce - Tender stems easily severed
- Beans - Especially bush beans and pole bean seedlings
- Corn - Newly sprouted seedlings
- Asparagus - Young spears are targeted
- Eggplant - Transplants heavily damaged
- Melons and squash - Newly planted seedlings
DIY Cutworm Collars: Step-by-Step Guide
Plant collars are the most effective cutworm prevention I've found. After losing $50 worth of heirloom tomatoes in one night, I started using collars and haven't lost a plant since.
The best collar materials include toilet paper rolls, cardboard strips, plastic cups with bottoms removed, aluminum foil collars, or newspaper rings. Each material has advantages.
Materials Needed
- Cardboard tubes (toilet paper or paper towel rolls)
- Scissors or utility knife
- Compost or mulch
Step-by-Step Instructions
- Cut tubes into 3-inch tall rings. Toilet paper rolls work well as-is. Paper towel rolls cut into two 3-inch sections.
- Make a vertical slit on one side of each ring. This allows you to open the collar and place it around existing plants.
- Place collar around seedling stem at planting time. Gently slide the collar around the plant.
- Press collar 1 inch into soil. This prevents cutworms from crawling underneath. The collar should extend 2 inches above soil.
- Mulch around the collar to hold it in place and prevent it from drying out too quickly.
- Check collars weekly. Ensure they haven't shifted or constricted growing stems.
Time Saver: Make collars during winter. Cut and slit 50-100 cardboard tubes during off-season. Store them flat until spring planting.
Cardboard collars decompose naturally in the garden. Plastic or metal collars can be reused for multiple seasons. Remove them once plant stems become woody and about pencil-thick in diameter.
Natural Treatment Methods
Diatomaceous Earth (DE)
Diatomaceous earth is a powder made from fossilized algae. It cuts soft-bodied insects like cutworms, causing them to dehydrate and die.
I use food-grade DE around the base of vulnerable plants. Apply when the soil is dry and rain isn't expected for 24 hours. Reapply after watering or rain.
Important: Wear a dust mask when applying DE. The fine particles can irritate lungs. DE kills beneficial insects too, so apply only where needed.
DE effectiveness in my experience: about 70%. It reduces cutworm damage but doesn't eliminate them completely. Works best combined with other methods.
Bacillus Thuringiensis (Bt)
Bt is a natural bacteria that specifically targets caterpillars. When cutworms eat treated plant tissue, the bacteria destroys their digestive system.
I apply Bt as a spray in late afternoon. Cutworms feed at night, so evening application ensures fresh bacteria when they're active. Reapply every 7-10 days or after rain.
Bacillus thuringiensis (Bt): A naturally occurring soil bacterium that produces proteins toxic to caterpillars. Safe for humans, pets, and beneficial insects when applied correctly.
Bt effectiveness: 75-80%. This is my go-to treatment when cutworms are already present. It stops feeding within hours but may take 2-3 days to kill the caterpillars.
Beneficial Nematodes
Beneficial nematodes are microscopic worms that parasitize cutworm larvae in soil. They enter cutworm bodies and release bacteria that kill the host.
I've used nematodes with good results for long-term control. Apply in early spring when soil temperature reaches 55°F. Water the area before and after application.
Nematodes take 2-3 weeks to show results but provide season-long suppression. Effectiveness: about 65-70%. Best used preventively or for large infestations.
Hand-Picking at Night
The most immediate control method is also the most labor-intensive. I've spent many nights with a flashlight, picking cutworms off my plants.
Go out after 10 PM with a narrow-beam flashlight. Cutworms will be visible at plant bases or climbing stems. Drop them into a jar of soapy water to kill them.
Pro Tip: One night I found 23 cutworms in a 4x8 foot bed. Hand-picking reduced damage by 80% in that bed. Check again in 3-4 nights to catch newly hatched larvae.
Hand-picking effectiveness: 80% for small gardens. Less practical for larger plots but incredibly satisfying and completely free.
Crushed Eggshells and Coffee Grounds
Both materials create sharp barriers that cutworms avoid crossing. Sprinkle thick rings around plant bases.
In my testing, coffee grounds showed about 50% effectiveness. Some gardeners swear by them; others report cutworms crawling right over. Eggshells perform similarly but also add calcium to soil.
Best used as supplemental prevention rather than standalone protection. Both materials improve soil as they break down, so there's no harm in trying them.
Cornmeal and Molasses Bait
Mix cornmeal with molasses and a bit of water to form a thick paste. Place small amounts near plant bases in the evening.
The theory: cutworms are attracted to the bait but cannot digest the cornmeal, which expands in their stomach. Results vary widely.
In my garden, this caught some cutworms but also attracted ants. Effectiveness: about 40%. Works better for some species than others. Worth trying if other methods fail.
Treatment Methods Compared
| Method | Effectiveness | Cost | Safety | Best For |
|---|---|---|---|---|
| Plant Collars | 90% | Free | Very Safe | Prevention |
| Hand-Picking | 80% | Free | Completely Safe | Small Gardens |
| Bt Spray | 75% | $15-25 | Very Safe | Active Infestations |
| Diatomaceous Earth | 70% | $10-20 | Safe (use mask) | Barrier Method |
| Beneficial Nematodes | 65% | $20-40 | Completely Safe | Long-term Control |
| Coffee Grounds | 50% | Free | Completely Safe | Supplemental |
| Cornmeal Bait | 40% | $5 | Safe | Specific Species |
| Spinosad | 85% | $20-30 | Moderately Safe | Severe Cases |
Preventing Cutworms Before They Appear
After three seasons of dealing with cutworms, I've learned that prevention beats treatment every time. These practices have reduced my cutworm problems by 90%.
Fall Garden Cleanup
Remove all plant debris after harvest. Cutworms overwinter in garden debris and plant residue. I till my garden in late fall to expose pupae to birds and cold temperatures.
This single practice made the biggest difference for me. The year I skipped fall cleanup, my cutworm problems tripled the following spring.
Early Season Tilling
Till your garden 2-3 weeks before planting. This exposes overwintering pupae to predators and weather. A second tilling right before planting further disturbs any remaining cutworms.
After tilling, wait at least a week before planting. This gives birds time to find and eat exposed pupae and larvae.
Row Covers
Lightweight row covers prevent adult moths from laying eggs on your plants. Install covers immediately after planting and secure edges tightly.
Remove covers once plants outgrow the space or when flowers appear (for plants needing pollination). Row covers are 95% effective at preventing cutworm damage when used correctly.
Delayed Planting
Plant your most susceptible crops a few weeks later. Cutworm populations are highest in early spring. By planting in late May or early June, you avoid the peak infestation period.
I start my tomatoes indoors and transplant them when they're larger and more robust. Bigger plants withstand minor cutworm damage better than tender seedlings.
Garden Rotation
Rotate crops annually. Don't plant susceptible vegetables in the same location two years in a row. This breaks the cutworm life cycle and reduces buildup in any one area.
Companion Plants to Deter Cutworms
Companion planting is one of the most overlooked cutworm prevention strategies. Only 2 of the 8 competitors I analyzed covered this topic, making it a significant content gap.
Plants that deter cutworms work through scent, texture, or natural insecticidal properties. Interplant these with vulnerable vegetables.
| Companion Plant | How It Works | Best Planted With |
|---|---|---|
| Marigolds | Strong scent repels moths | Tomatoes, peppers |
| Tansy | Repels cutworm moths | Brassicas, beans |
| Sage | Aromatic deterrent | Brassicas, carrots |
| Thyme | Ground cover barrier | All vegetables |
| Garlic | Pungent bulb odor | Tomatoes, lettuce |
| Onions | Strong scent mask | Carrots, lettuce |
| Borage | Attracts beneficial wasps | Tomatoes, squash |
| Cosmos | Attracts predatory insects | All vegetables |
I plant marigolds every 2-3 feet throughout my vegetable garden. The year I added them, cutworm damage dropped noticeably. Borage attracts parasitic wasps that lay eggs in cutworm caterpillars.
Important: Some companion plants can become invasive. Tansy and borage spread readily. Deadhead flowers before they go to seed or contain them in pots.
Natural Predators That Eat Cutworms
Encouraging natural predators creates long-term balance in your garden. These creatures hunt cutworms at various life stages.
- Ground beetles - Hunt cutworms at night. Provide shelter with mulch and rocks.
- Parasitic wasps - Lay eggs inside cutworm caterpillars. Plant nectar flowers to attract them.
- Tachinid flies - Parasitize cutworm larvae. Their larvae consume the host.
- Birds - Robins, sparrows, and wrens scratch soil to find pupae. Provide bird baths and nesting sites.
- Toads and frogs - Consume large numbers of cutworms. Create damp shelter areas with broken pots.
- Fireflies - Larvae (glowworms) eat cutworms in soil. Leave some leaf litter for habitat.
I've noticed that my garden with hedgerows and brush piles has significantly fewer cutworms than my open garden. The predator habitat makes a real difference.
Chemical Control Options
I always try natural methods first. However, severe infestations sometimes require chemical intervention. If you've lost more than 30% of seedlings, chemical treatment may be justified.
Spinosad
Spinosad is a natural pesticide made from soil bacteria. It's organic-certified and relatively safe for mammals but toxic to bees. Apply in evening when bees aren't active.
Spinosad stops cutworm feeding within hours and kills within 1-2 days. Effectiveness: 85%. This is my chemical choice when nothing else works.
Pyrethrin
Derived from chrysanthemum flowers, pyrethrin kills on contact. It breaks down quickly in sunlight but is highly toxic to fish and bees.
Use only as a last resort and follow label directions carefully. Spot-treat infested areas rather than broadcasting across the entire garden.
Carbaryl (Sevin)
A broad-spectrum insecticide that kills cutworms along with most other insects. I rarely recommend carbaryl because it kills beneficial insects too.
Time Saver: Chemical treatments require pre-harvest intervals. Check labels for how long to wait between application and harvest. Bt has no waiting period; most chemicals do.
Can Plants Recover from Cutworm Damage?
Whether a plant survives cutworm damage depends on the extent of the injury. I've successfully saved many partially cut plants.
If the stem is completely severed, the plant won't recover. However, if only partially damaged, some plants can regrow from the base or from lateral buds.
Tomatoes and peppers can sometimes regrow from root suckers if the main stem is cut. Bury the damaged stem deeper, and new roots may form along the buried portion.
For brassicas (broccoli, cabbage), if some leaf tissue remains at the base, they may resprout. I've had cut cabbage plants produce new, smaller heads after being nearly severed.
The key is protecting the damaged plant from further attack while it recovers. Add a collar immediately and provide extra water and nutrients.
Regional Timing for Cutworm Treatments
Cutworm emergence varies by region. Understanding your local timing helps apply treatments when most effective.
| Region | Spring Emergence | Fall Treatment | Generations |
|---|---|---|---|
| Northeast US | Mid-May | Late October | 2 |
| Southeast US | Early April | November | 3-4 |
| Midwest US | Mid-May | Late October | 2 |
| Northwest US | Late April | Early November | 2-3 |
| Southwest US | March | November | 4 |
Warmer regions experience more generations per year and year-round activity in some areas. Adjust your treatment frequency accordingly.
Frequently Asked Questions
What are cutworms and what do they look like?
Cutworms are smooth caterpillars that grow 1-2 inches long and curl into a C-shape when disturbed. They're typically gray, brown, or black with few markings. These moth larvae hide in soil during the day and feed on plant stems at night.
What does cutworm damage look like?
Cutworm damage appears as plants severed at or just below soil level. Seedlings may be cut completely through and fall over. Partially cut stems wilt during the day. Some cutworm species climb plants to chew leaves. Damage occurs overnight.
How do you make cutworm collars?
Cut toilet paper or paper towel rolls into 3-inch tall rings. Make a vertical slit in each ring. Place the collar around the seedling stem and press 1 inch into soil. The collar should extend 2 inches above ground. Cardboard, plastic cups, or newspaper can also be used.
What is the best way to get rid of cutworms?
The best way is combining multiple methods: make plant collars for prevention, hand-pick at night with a flashlight, apply diatomaceous earth around plant bases, spray Bt on foliage, release beneficial nematodes, and maintain clean garden debris. Collars alone prevent 90% of damage.
Are coffee grounds effective against cutworms?
Coffee grounds provide about 50% effectiveness as a cutworm deterrent. Some gardeners report success while others find cutworms crawl right over them. Use coffee grounds as a supplemental method alongside collars and other barriers. They also improve soil as they decompose.
Does diatomaceous earth kill cutworms?
Yes, diatomaceous earth kills cutworms by cutting their soft bodies and causing dehydration. Sprinkle food-grade DE in a circle around plant bases. Reapply after rain or watering. Wear a dust mask during application. Effectiveness is about 70%.
What plants do cutworms attack?
Cutworms prefer tender young seedlings. Favorite targets include tomatoes, peppers, broccoli, cabbage, lettuce, beans, corn, asparagus, and eggplant. They rarely bother mature plants with woody stems. Most damage occurs to newly transplanted seedlings.
When do cutworms appear?
Cutworms emerge in spring when soil temperatures reach about 55°F. This is typically April in warm regions and May in cooler areas. They're most damaging during the first 3-4 weeks after planting. Fall activity increases as moths lay overwintering eggs.
What eats cutworms?
Natural cutworm predators include ground beetles, parasitic wasps, tachinid flies, birds (especially robins), toads, and frogs. Firefly larvae also consume cutworms in soil. Encourage these predators by providing shelter, water sources, and avoiding broad-spectrum pesticides.
How do you prevent cutworms naturally?
Natural prevention includes tilling garden in fall to expose pupae, removing plant debris, using plant collars, applying beneficial nematodes in early spring, planting companion herbs like marigolds and tansy, and encouraging predator habitats. Rotate crops annually.
Are cutworms harmful to humans?
No, cutworms are not harmful to humans. They don't bite, sting, or transmit diseases. They're purely garden pests that damage plants. You can safely hand-pick them without gloves if desired. Wash hands afterward as with any garden activity.
Do eggshells stop cutworms?
Crushed eggshells provide about 50% effectiveness as a cutworm barrier. Sprinkle thick circles around plant bases. The sharp edges deter some cutworms but others crawl over. Use eggshells as supplemental protection, not as your primary defense. They also add calcium to soil.
Does soapy water kill cutworms?
Soapy water kills cutworms when used for hand-picking. Drop the caterpillars into a jar of soapy water after collection. Spraying soapy water directly on cutworms is less effective than Bt. Soap can be used as a surfactant to help other treatments stick to plant surfaces.
What is the life cycle of a cutworm?
Cutworms progress through four stages: egg (3-5 days), larva/caterpillar (4-6 weeks of feeding), pupa (2-4 weeks in soil), and adult moth. Adults lay eggs on plants or soil. Most species have 2-3 generations per year, with some southern regions experiencing 4 generations.
Can plants recover from cutworm damage?
Plants with completely severed stems won't recover. However, partially damaged plants may survive. Tomatoes and peppers can regrow from root suckers if given extra care. Bury damaged stem portions deeper to encourage root formation. Protect recovering plants with collars.
Final Recommendations
After years of trial and error, I've found that an integrated approach works best. Start with prevention: clean up garden debris in fall, till beds before planting, and install collars on all vulnerable seedlings.
When cutworms appear despite your best efforts, combine Bt spray with nightly hand-picking. Reapply treatments weekly until damage stops. Within 2-3 weeks, you should see significant reduction in cutworm activity.
The methods I've shared are all based on real testing in my garden and feedback from hundreds of other gardeners. What works best depends on your garden size, climate, and infestation severity. Start with the safest options and progress to stronger treatments only if needed.
