Nothing ruins a gardener’s spring quite like a cutworm infestation. You go to bed one night with a beautiful bed of thriving vegetable starts, and when you wake up the next morning they’ve been chopped down and harvested like timber.
Luckily there are a ton of easy, effective, inexpensive solutions that you can use in combination to get rid of cutworms fast.
How To Get Rid of Cutworms
1. Keep seedlings indoors Away From Cutworms longer
Cutworms will still eat older plants, but this could involve eating holes in the leaves or fruits of the plant, rather than killing the entire plant. That means you can reduce the likelihood of damage to your seedlings by not planting them too early.
Cutworms are most active at the very beginning of spring, when they come out of winter hibernation. Keeping your seedlings in your greenhouse or grow room until a little later in the spring, when the plants are studier, reduces the risk of them being decimated by cutworms. Even a couple of extra weeks of protection can make a major difference.
2. Floating row covers
A floating row cover is a protective (but sun- and rain-permeable) tunnel that you can install over your garden beds to keep garden pests like cutworms out. A floating row cover consists of:
- The framing (half-circle arches made of metal wire or PVC pipe, for example) with the ends buried in the ground on either side of your row or bed,
- The fabric (a gauze-like polyester or polypropylene) that covers the frame to keep pests out, and
- Something heavy (like bricks) to weigh the ends of the fabric down.
Floating row covers protect your plants from cutworms, but also other insects like aphids, flea beetles, cucumber beetles, squash bugs, cabbage maggots/loopers/worms, and more!
Note: Floating row covers aren’t just great for insect pests. They also protect your plants from bigger pests like rabbits, deer, birds, and even neighborhood pets. As an extra bonus, they offer thermal protection against late-spring surprise frosts.
Floating row covers are a great multi-purpose investment. However, make sure to remove them from any insect-pollinated plants (such as tomatoes and squash) when the plants begin to flower. Otherwise, you may protect your plants from cutworms and still end up with nothing to harvest.
3. Reusable plastic cutworm collars
While this is not a feasible solution for large-scale farmers, people with smaller gardens can protect their plants individually by blocking cutworm access to each seedling. Just like royals protected their castles with moats, you can protect your seedlings with “cutworm collars.”
You can make reusable cutworm collars yourself using large disposable plastic cups. Ideally don’t buy plastic cups just for this project, but if you have a party you could rinse out the used cups and reuse them for this purpose.
- Cut off the bottoms of the cups.
- Place the cup over your seedling so the seedling is contained within it.
- Press the edges of the cup so they go down into the soil at least an inch, and stick out above the soil at least two inches.
This is an effective cutworm barrier. At the end of the season, your cup-collars can be rinsed off and stacked together for easy storage until next spring.
4. Reusable metal cutworm collars
If you face cutworm problems year after year, it might be worth investing a little time and money in making bigger and sturdier cutworm collars. Here’s how to make reusable metal cutworm collars:
- Visit your local building or hardware store and purchase aluminum flashing with 6” width. The lighter, the better.
- Use metal snips to cut the flashing to 2” strips. This will give you 2”x6.”
- Fold the strips to get a triangle collar.
- Fit the triangle flashing over the seedling stem.
5. Disposable Cardboard Tube Cutworm Collars
You can make quick and easy cutworm collars from cardboard. However, these collars will not stand the test of time. You will need to throw them out after one season and start again next year.
You can use the leftover cardboard tube from an empty toilet paper or paper towel roll. This option is ideal because the entire tube is compostable. By summer it will start to biodegrade, and you can leave it or mix it in with your soil to encourage it to decompose. However, these tubes are a bit narrow for larger seedlings.
6. Disposable DIY Cardboard Cutworm Collars
If you don’t have any empty cardboard tubes to reuse, or you want to make larger cutworm collars, you could cut a rectangle out of cardboard, form a circular or squared-off tube, and tape together the two opposite ends that are touching.
Make sure that when you’re done using the tube you remove the tape before digging it into the soil or throwing it on your compost pile. Don’t use cardboard with a plastic coating if you want to compost it.
7. Aluminum Foil
Another easy disposable option is to use aluminum foil. Instead of creating a tube to go around the plant, you wrap the stem itself with foil so the worms can’t munch through it. Unlike cardboard, this does add garbage to a landfill.
8. Grow in pots or planters
Some varieties of cutworm will climb vertically (for example climbing plants in the summer to eat the leaves). However, most live in the ground and attack at ground level. That means growing your plant in a pot should prevent cutworms from accessing your plant. While this obviously isn’t feasible for something like a corn crop, if you do have a major cutworm problem and a couple of special plants you want to protect, you could do that by simply not growing them in the ground.
Crushed eggshells can be scattered around the base of plants to deter cutworms. You can collect a bunch of shells and then grind them up in a blender or food processor. Don’t turn the shells into a powder.
Eggshells are a great option because in addition to deterring cutworms, they are also a great soil amendment. They add calcium to the soil, which makes them especially great for tomato beds (although it does take quite a while for the eggshell to break down and become bioavailable).
10. Oyster shells
Crushed oyster shells are another great cutworm deterrent. Just like eggshells, oyster shells are rich in calcium and make an excellent soil amendment on top of the pest control benefits. However, if you’re going to crush them yourself, instead of buying the product commercially, make sure to sterilize the shells in boiling water first.
According to some credible sources, sand is gritty enough to work as a cutworm deterrent. However, given that sand is commonly found in garden soil, this seems less likely to be successful than some of the other options that have a sharper grit.
If you are going to use sand, make sure to use coarse builders’ sand, not fine sand like the kind you’d use in a kid’s sandbox.
12. DIY cornmeal bait trap
Cornmeal or bran meal can be used to protect your plants. Cutworms find it tasty, but can’t digest it, so it kills them. There are two ways you can use it to bait cutworms.
- You can make a “trap” from a shallow dish buried so that its rim is at the level of the soil.
- Fill it with cornmeal and the cutworms will crawl in to eat it.
- The alternative is to sprinkle cornmeal around the base of your plants. Use around 1/2 teaspoon.
Note: You will need to reapply frequently if you use this method, because the corn begins to disintegrate fairly quickly. On the plus side, cornmeal is good for your garden, providing an organic nitrogen fertilizer as it decomposes.
13. Coffee grounds
Coffee grounds can reportedly be used like eggshell or oystershell grit. You encircle your plant with a ring of it, and the texture may deter cutworms. Even if it doesn’t stop cutworms, coffee grounds provide a great nitrogen boost to your garden soil when they decompose.
14. Epsom salt
Epsom salt is another commonly recommended gritty household substance you can use in your garden.
Note: While Epsom salt sprinkled around your plant is gritty enough to deter most cutworms, it can have a negative effect on your garden.
Epsom salt contains magnesium, and can be used to supplement a deficiency of magnesium. That means adding it without a deficiency can cause an overload of magnesium in your soil, which can impair your plants’ ability to uptake nutrients from the soil. So while it may work against cutworms, we don’t recommend using Epsom salts unless you’ve tested your soil and discovered a magnesium deficiency.
15. Grow Companion Plants
Tansy and spiny amaranth, grown as companion plants, reportedly repel cutworms. Tansy is well known as a natural insecticide. It is effective with many pest insects, such as ants, flies, asparagus beetles, and squash bugs. Tansy also produces clusters of cute, button-shaped flowers, so you may as well try it. You can also use cut tansy to make a tea that you can use as an insecticide spray.
Perhaps the most common cutworm solution for gardeners is also the most low-tech, but it is free and works great for small gardens.
You simply inspect your plants in the early evening, one by one, using a flashlight. When you find the larvae, pick them off and either drop them into a container of soapy water to drown them, or cut them in half with scissors. Don’t just try to squish them, as they may survive.
You’ll need to do this every few nights until you run out of cutworms. The NC State Extension Office has more extensive advice on how to inspect your seedlings for insects like cutworms. It is a time consuming process, but worth it if it protects your plant babies.
You should also keep an eye out for cutworm eggs, which are usually laid on the plants near the soil level. They are creamy-white in appearance. You can see some examples of cutworm eggs here.
17. Investigate the scene of the crime
If any of your plants do get taken down by cutworms, make sure to check the soil around the base of the plant the next morning. The cutworm, stuffed with its plunder, may have stuck around long to be caught and punished for its crimes.
18. Till the field
While tilling is not always a great option for weed control, it can be a big help in controlling cutworms in large areas. In the fall after the crop is harvested, and again at least ten days before planting, till your field.
This will kill some of the cutworms that have survived the winter, but it will also bring many of them up to the surface in the daytime, which makes them vulnerable to predators.
If you have a good bird population, they may eat up the cutworms for you. You could also let a hog or chickens loose in the field to feast to their heart’s content.
19. Essential oils
Research has shown that lemongrass essential oil is an effective alternative to using chemical pesticides to kill cutworm. Essentria IC-3 is an essential-oil based insecticide that meets organic standards and claims efficacy against cutworms.
20. Diatomaceous Earth (DE)
One option that is effective but generally best avoided is diatomaceous earth (D.E.). This powder sticks to any insects that touch it and dehydrates them to death. D.E. is “natural,” but it is also an indiscriminate killer of insects that will kill beneficial insects, including pollinators like bees and butterflies. If you must use D.E., place it at the base of the seedling where it is less likely to affect pollinators.
21. Wood Ashes
You can sprinkle wood ashes around the base of your plants to kill or deter cutworms, but this is a labor-intensive option. The gritty powder of ash is very bad for cutworms, but only until it gets wet. That means you will need to reapply it frequently, at a minimum after each rain but possibly more often. The problem with this, other than the effort, is that adding excessive amounts of wood to your soil can raise the pH to a level that is bad for your plants.
Wood ash also has many other uses in your garden. Read about them here.
22. Bt (Bacillus thuringiensis)
There are many other options to try first, but if you must use insecticide, the best method is to use insecticide bait before your seeds sprout or your seedlings are transplanted.
There are several common options, including Bt (which is acceptable for organic farming), but keep in mind that it will also kill caterpillars that would otherwise become pollinating butterflies.
General application spray pesticides are a solution of last resort. If you must use a pesticide, it is important to choose an option with the lowest negative environmental impact, in terms of killing beneficial insects like bees and butterflies.
The University of California’s Integrated Pest Management Programs has a list of pesticides scored and ranked taking into account their effectiveness against cutworms and their environmental impact.
If you do use insecticide, an application in the early evening will increase its efficacy (in terms of killing caterpillars) and reduce the likelihood of killing bees.
23. Attract Insects That Eat Cutworms
A variety of predatory insects feed on cutworms. These include parasitic wasps, tachinid flies, green lacewing, and predaceous ground beetles.
While the term predatory insect may make them sound scary, attracting them to your garden is a great idea if you want to protect your plants. They’ll eat not just your cutworms but aphids and many other insects that can devastate your garden.
One of the best ways to attract predatory insects is to plant certain types of flowers they find appealing, but you can also purchase them.
24. Clean up debris
If you have a cutworm problem, and even if you don’t, it’s best to add your plant debris to your compost pile, rather than allowing it to compost in place.
Cutworms hibernate under organic material, so it should come as no surprise that studies have found higher rates of cutworms in fields left covered in plant debris after the growing season is over. Cleaning up your garden beds properly at the end of the season can reduce a variety of pests.
25. Weed control
Studies have found higher rates of cutworms in fields with weed growth. That means keeping your garden cleanly weeded, or even covering empty beds with cardboard or tarp, could reduce your cutworm problems come spring.
26. Use Compost Instead of Cover Crops
For similar reasons, cover crops can encourage cutworm egg laying just like weeds and garden debris. Using compost instead of cover crops for weed suppression and fertilization can reduce a cutworm problem.
27. Create a Garden Border
Cutworms don’t like crawling long distances out in the open or in dry soil. Keeping a buffer zone of 3-4 feet of dry soil around your garden’s perimeter—with no weeds, grass, or debris—will help discourage them from invading your garden.
28. Beneficial nematodes
Beneficial nematodes are microscopic worms that you can add to your soil. They eat soil-dwelling insects like cutworms and the grubs of Japanese beetles. Research has shown that certain beneficial nematodes can be very effective at fighting cutworms.
29. Cayenne pepper
Some sources report you can deter cutworms by sprinkling cayenne pepper around the base of the plant, like you might use a gritty substance. However, cutworms are well known to eat cayenne pepper plants, so this might be worth trying as an experiment, but low on the list of things to try.
30. Bamboo Skewers / Toothpicks
You can brace the sides of your plants’ stems with toothpicks to stop cutworms from attacking them. The toothpicks make it more difficult, reportedly, for the cutworm to grip the stem in order to munch on it.