How do I get rid of worms on my mint plant?
So, you have cabbage loopers on your mint. And you need to get rid of them!
In this easy-to-follow guide, we’ll cover the following topics:
- What’s eating your mint plant
- Signs of loopers on your mint
- How to get rid of a caterpillar infestation
- Home remedies to kill loopers
- How to protect your mint from pests
- And more!
You’ll have everything you need to know by the end of this page.
If you have any questions, drop me a line below and I’ll help you out!
Bookmark this page so you can easily refer back to it.
Sound good? Let’s protect your mint from caterpillars!
What’s a looper worm?
A looper worm, also known as a cabbage looper, is a common moth that attacks over 160 different host plants.
- Note that it’s FIRST a caterpillar. But it PUPATES into a moth as an adult.
- They’re the SAME pest. But DIFFERENT parts of its life cycle.
Don’t get confused over this.
They’re actually not that destructive as a pest but will harm plants over time if they have large populations. Their larvae form is the looper worm you’re familiar with.
The common green caterpillar gets its name because it arches the back into a loop when it moves around. These caterpillars pupate and eventually emerge as an adult moth.
They’re similar to other plant-based pests, such as basil pests.
The cabbage looper eats mint just like any other plant and leaves nasty damage. You’ll often find holes and torn leaves.
But don’t worry, we’ll cover some home remedies to kill these caterpillars.
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There are two popular species of looper worms:
- Alfalfa looper
- Cabbage looper
They’re similar but different. Don’t worry too much about the difference. We’re focusing on the latter only.
Some other common names for loopers:
- Cabbage looper
- Looper worm
- Looper caterpillar
- Cabbage caterpillar
- Cabbage moth
- Mint moth caterpillar
Looper worms have two distinct parts of their lifecycle that you should be familiar with.
The first is the adult form. This is a moth that’s dark brown in appearance. It has two long antennae with noticeable front limbs. There are also two beady and big eyes that are easily seen.
Their wingspan usually consists of a mixture of colors and patterns, depending on the species and environment. It may be black, brown, or rusty colored.
The adult from flies around, mates, and deposits eggs on host plants.
The second is the caterpillar or larval form. This is the looper that you’re familiar with. It has a lengthy, segmented body that curls up to a loop every time it moves.
There are noticeable colorations and patterning that extend down the body. The head is darker and shaded. There are noticeable hairs. The body is ½” in length and can be green, lime, or any tone of the two.
Tiny white worms
They usually are white and have many hairs when born. But over time, they’ll shed the hairs and end up with just a few bristles. They’ll also change from being a white worm to a green one.
They’re also sometimes described as little green caterpillars or tiny white bugs. The “white bug” portion is when they first emerge from the egg. Then they turn into the “little green caterpillars” over time. As they eat mint, they’ll stay on the host plant until they pupate into an adult moth with wings.
Looper life cycle
Loopers have a complex life cycle that goes through many different forms of the same individual.
An adult looper deposits her eggs
It starts with an adult female looper who will deposit her eggs. In a single day, a female can lay hundreds of eggs.
The eggs are laid and will hatch in 3 days. Not all eggs hatch, but the majority do.
They leave eggs on plant leaves that are higher up on the plant and larger. You’ll often find looper eggs on the largest mint leaves possible.
Cabbage looper larvae
After a few days, the larvae emerge from the egg. The cabbageworm is green and white with a noticeable white stripe across the side. They’re hairy at this point.
You may notice white worms on your mint, which could be larvae of cabbage loopers. They actually don’t eat much food at this point, but will quickly change that.
The pupa is next. After about 2 weeks, the larvae will turn from white to green and shed most hairs. It’ll find a place to pupate and spin a silky cocoon.
This can take up to two weeks depending on temperature and environment. You’ll often find cocoons on the underside of large leaves.
The adult form will then emerge from the cocoon. The moth is about 2.5cm in length and is nocturnal. They’re usually active 30 minutes before sunset.
What keeps eating my mint?
There are many pests that could be eating your mint plant. The important part is to take notice of how the damage looks like.
- Are there are a bunch of random holes in the plant?
- Do you see shed cocoons?
- Do you see visible pests?
- Are there any bugs in the soil?
- Do you see chewed or torn parts?
- Are there adult moths landing on the leaves?
- Are there eggs on the stem or leaves?
- Do you see sticky substances on the plant?
If you answered “yes” to most of these, the pest may be cabbage loopers.
What do looper worms eat?
Loopers eat vegetables and mainly focus on crucifers. They’re becoming more of a pest across the US and researchers are looking for control methods because of their vast numbers.
They eat a variety of veggies you may be growing in your yard. If you have a vegetable garden, they may be eating more than just your mint plant.
Some other plants that cabbage loopers eat:
- Cabbage (all colors)
- Brussel sprouts
They’re especially attracted to cruciferous vegetables because they grow quicker on them. Vegetables with strong odors or aromas also make prime targets for them.
What causes holes in mint leaves?
There are many bugs that feed on mint.
What do you expect with such a pleasant and powerful aroma? If you find holes all over your mint leaves, it’s likely a caterpillar. Like the stereotypical hungry caterpillar, these bugs will chew up your mint leaves nonstop.
They’re active during the night, so they’re hard to spot. Since most people sleep at night, this makes them an annoying pest to deal with.
Both of these are similar pests, but the cabbage looper is much more commonly found on mint.
Loopers are known to eat over 160 different plants. The adult looper is actually a moth, which comes from the larvae form as a caterpillar.
Other than the many destructive holes they leave in your mint leaves, they also leave behind poop- or frass.
The grass is sticky and can contaminate the plants you eat. It can trap bacteria from other bugs that walk across it, and it can harbor disease.
You should dispose of mint leaves that have holes in them because of possible looper worms.
How to tell if you have looper caterpillars
The damage they do is obvious.
Look for these common telltale signs of a looper pest problem:
- Holes in your plant leaves
- Sticky, dark substances on the leaves
- Visible looper caterpillar
- Cocoons under plant leaves
- Small, tiny white bugs
- Shed cocoon shells
- Eaten or jagged leaves
- Adult cabbage moths on the leaves
Where are loopers found?
It’s found all over North America and other parts of the world.
It’s migrating species, so you’ll only see it infest your mint certain parts of the year.
They migrate from Mexico to Canada and overwinters in Southern California.
Florida is another US state where loopers are common, along with Texas. This pest is everywhere- even at high altitudes and far from the shore. They can fly up to 200 km.
They’re most active during the summer for most homeowners.
- During the winter, it’s found in southern states.
- During the summer, it’s found in northern states.
They’re also attracted to any odor. And mints are known for their spicy odor. Thus, it’s a perfect match to find these bugs in your herbs.
Are cabbage worms harmful to humans?
There is no known evidence that they’re harmful to humans. These worms don’t bite, sting, or carry diseases.
However, they do leave behind frass, which is sticky and can attract other pests and bacteria. You should still be very cautious and use protective equipment when handling these bugs.
Are they poisonous?
No, cabbage loopers are not poisonous and don’t have the ability to inject or sting. They’re harmless towards humans, but you should be careful of the frass left behind.
Can you eat cabbage worms?
Since these pests leave behind sticky frass which attracts a lot of bacteria and other pests, you should avoid eating plants where cabbage worms have been present.
Cooking the raw vegetables may kill any harbored bacteria, but you should avoid eating cabbage worm-infested foods when possible.
How do you get rid of a looper caterpillar infestation on mint?
Loopers worms are a common pest of tasty mint plants.
To control them, it can be difficult due to the sheer number of caterpillars that can be present.
Depending on how long the infestation has been going on, you may be able to get rid of the loopers faster than you think.
Here are some natural home remedies you can try to quickly reduce the caterpillar population on your mint plants.
Remove them by hand
This is the brute force method of ridding looper worms.
Grab a bucket and fill it up with soap and water. You can use dish soap. Add 8 drops per cup of water until you have a few cups in the bucket.
Put on a pair of garden gloves and head out to your mint plants. Carefully check the plant for loopers and pick them off.
Then toss them into your bucket of soapy water. This will drown them and kill them nearly instantly. Repeat this process daily until no more appear.
Note that looper worm eggs hatch based on the season and often come in waves.
You’ll often find a bunch of caterpillars appear suddenly out of nowhere. Then you’ll see periods of no caterpillars at all. Then the cycle repeats.
The trick is to slowly but surely reduce the population until there are none left.
When you check your mint plant, it’s easy to miss cabbage loopers because they can camouflage and blend in.
Be sure to check the following areas:
- Under mint leaves
- On the mint stems
- On the soil surface
- Leaf tips
Get rid of the looper eggs
Looper worms lay their eggs on the mint leaves and often by the dozen.
This is why you can have a sudden breakout of caterpillars all over your mint plants overnight. To stop their lifecycle, you can get rid of the caterpillar eggs.
Since they often lay eggs in predictable locations, you can check those areas on your mint to see if you can find eggs to remove.
Cut the mint back
Caterpillar colonies expand proportionally to the amount of food (your mint) available. If you have an established mint plant that’s large, there will be more caterpillar activity. It’s basic ecosystems.
If the food source is available and can sustain a large colony of loopers, then they’ll continue to feed and reproduce until there isn’t enough food available.
You can actually artificially control the caterpillars by cutting back on your mint leaves. Prune them and you’ll see the looper population drop off significantly.
Because there’s a reduction in the available food, the number of loopers will also reduce.
You’ll also cut out a lot of caterpillar eggs in the process. Even if they hatch, they’ll have a difficult time to grow because of the reduction in plant matter for them to eat.
Your mint plant grows back quickly and nicely, but the caterpillar reduction will take longer.
This “gap” between the mint plant’s growth and reduce caterpillar population can be your chance to get in there and really clean things up.
Remove the eggs as you see them. Kill the loopers as you see them. Do daily checks. This is an effective home remedy that kills caterpillars.
Make a baking soda mix for caterpillars
You can mix half baking soda and half water and then apply the mixture to kill cabbage worms. There seem to be mixed opinions on this method, and I’ve personally never tried it.
But I thought it’s worth mentioning since the baking soda can be lethal to other caterpillars. So it may work on cabbage loopers. Let me know if you try this technique.
Try neem oil
Another popular solution is to spray neem oil onto the cabbage worms to kill them. This is a natural pesticide that kills a variety of pests like thrips and rice bugs. Neem oil can be used on vegetables and mints without damage.
The nice part about using this control method is that it stays on the mint for a few days so you don’t need to constantly apply it again.
You can buy organic neem oil at specialty stores. Mix a few drops of the oil with water and then spray your mint plant with it. Don’t use neem oil in direct sunlight because this can bake the plant. Use it after sundown. Wash the mint before you eat it.
If you’re paranoid, use the neem on a small part of the plant first. Then check for damage. Or if you notice that your mint plant is burning from the neem, use less oil. This shouldn’t happen, but you’ll want to keep a watchful eye.
Use natural sunlight
Caterpillars will shy away from the sun, as they feed at night. Most loopers are nocturnal and only feed at night.
This is also why they can be hard to get rid of- who wants to go outside at night to pick caterpillars off their mint? Especially those that are squeamish.
If your mint is potted, all you need to do is move the entire plant to somewhere that gets direct sunlight. You can move the plant inside to a window where sunlight is strong.
Just by relocating the mint plant, you’ll repel and deter the loopers and they’ll escape the plant.
Of course, if you have your mint planted into your garden, this won’t be possible.
Bacillus thuringiensis (Bt)
Bt is an organic solution of bacteria that can wipe out the looper population quickly. It’s a colony of organic bacteria that’s lethal to looper worms.
They produce a protein that the caterpillars eat. After they eat the protein, this will kill them. Bt is safe for humans because we can’t activate the lethal proteins.
However, the looper worms can. The gram-positive bacteria are commonly used as a pesticide for natural control. You can buy a vial of them online and use it as directed.
Note that you can avoid using Bt to kill the loopers on your mint if you don’t want to spend any money. DIY remedies like manual removal can work just as well, but again, they take time and effort to do so.
Spray with vinegar
Vinegar’s acidity proves to be an effective and cheap solution to rid bugs. Just use equal parts of vinegar and water and mix together into a spray bottle. Then spray it on the mint plant.
This will help keep the caterpillars off your mint. Apply as needed. Spray on the leaves and the soil.
Make a hot pepper spray
Hot peppers can be crushed into a spray and mixed with water.
You can use any pepper-like green chilies, cinnamon, jalapeno, or just regular pepper.
Blend the pepper seeds and water together, and then strain into a spray bottle. Now you should just have pepper water.
Use Tupperware and beer
Beer has long been a home remedy for many pests that eat plants.
Slugs and snails are two of the most common pests, but caterpillars can also be handled using the same approach.
Place a small Tupperware container into the soil around your mint plant and then fill it up with cheap beer. This will attract the bugs on your plants and kill them.
Replace the beer as often as needed. It only remains effective for a few days before it loses its appeal to the pests.
Just like hot peppers, you can use cinnamon powder as a natural solution to repel caterpillars.
The spicy scent and burning sensation will deter caterpillars. Just sprinkle a few tablespoons of cinnamon around the base of the plant.
You can also apply it directly to the mint leaves, as it won’t harm the plant. Any worm that crawls across it will feel the burn.
You can sprinkle diatomaceous earth around the soil where your mint stems out of the surface.
DE is a natural product that can repel any pests that need to crawl across the soil to get to your mint.
This can help stop new worms from crawling up a mint stem, but won’t stop the adults from flying directly onto the plant and laying eggs.
However, you can still use DE as a line of defense from soil-based pests. It also doesn’t hurt beneficial species like bees and butterflies. This is a home remedy that kills caterpillars.
Lastly, you can use natural predators that eat loopers to help you control your pest problem.
Smaller species eat looper eggs. If you have any of these pests in your yard, research how to attract more of them.
Then they can help you manage the looper eggs and larvae without you having to do anything. Once the eggs are stopped, there won’t be any more caterpillars.
A note about pesticides
Do NOT use pesticides to treat cabbage loopers in your mint.
This is because you’ll end up eating the pesticides when you harvest the mint. You should only use natural or organic methods for caterpillar control.
Cutworms on mint
If you have cutworms eating your mint plant, check out this guide for DIY cutworm pest control. I go in detail on how you can get rid of them for good.
Spider mites on mint
If you have spider mites, I have a guide for spider mite control.
Here are some more resources and references:
- Cabbage Looper – OKState
- Cabbage looper – Missouri Botanical Garden
Did you get rid of the cabbage loopers on your mint?
By now, you should have everything you need to manage and control these bugs.
You should be able to protect your mint from further destruction by using these DIY home remedies for looper control.
If you have a question, post a comment below.
Or if you found this page helpful, let me know anyway!
Currently an active researcher in the pest control industry for the past 8 years- with a focus on using natural and organic methods to eliminate pest problems.
I share handy DIY pest techniques I come across here to help out others (and possibly save them from a mental breakdown).
Fight nature with nature.