Controlling cabbage worms can be a constant battle for many home gardeners. In this post, you’ll learn all about their life cycle, feeding habits, the damage they cause, how to identify them, and where they come from. Plus I’ll share tons of tips and methods to help you get rid of cabbage worms in your garden.
Cabbage worms are a huge problem for many gardeners, and they can be very destructive little buggers. But there’s no reason to reach for the toxic chemical pesticides to get rid of cabbage worms!
Once you understand how they multiply, the plants they love the best, where they come from, what they look like, and the signs to look out for, it will be much easier to control cabbage worms.
Here’s what you’ll find in this guide for controlling cabbage worms…
- What Causes Holes In Cabbage Leaves?
- What Are Imported Cabbage Worms?
- What Do They Look Like?
- Cabbage Worm Life Cycle
- Where Do They Come From?
- What Do They Eat?
- Damage To Plants
- How To Get Rid Of Them Naturally
- Organic Treatment Methods
- How To Prevent Cabbage Worms
What Causes Holes In Cabbage Leaves?
If you see holes in the leaves of your cabbage, Brussels sprouts, broccoli, cauliflower, or any other plant in the cabbage family, it’s a sure bet that pesky caterpillars are the culprit.
There are actually a few types of bugs that mainly feed on the plants in the brassicaceae family. The most common ones are the imported cabbage worm, cabbage loopers, and the diamond back moth.
You may have one of these pests in your garden or a mix of them, depending on where you live. Here a quick summary so you can figure out what is eating your cabbage plant leaves…
- Imported Cabbage Worms – The main pest that feeds on the cole crops in my garden are the imported cabbage worm. They are green caterpillars that have legs along their entire body, and stay flat when the crawl. The adult butterfly is white with a few small black spots on their wings.
- Cabbage Loopers – The cabbage looper caterpillars are also green. They look similar to cabbage worms, but they are slightly larger. They also have less legs, and move like an inchworm, making a small loop shape with their bodies. The adult moth is brown with a cluster of small white spots on each wing.
- Diamondback Moths – Though much less common, diamondback moths also favor cruciferous vegetables. Their larvae are also green caterpillars, but will curl up and drop from the plant when disturbed, many times hanging from a thread of silk. The adult moth is brown, and commonly has a diamond shaped pattern across their back.
Since they all look so similar, many people mistaken cabbage loopers and diamondback moth larvae for cabbage worms. Though these aren’t all the same bugs, their life cycles, eating habits, and damage to plants are the same.
In this post, I will focus on the imported cabbage worm. But all of the organic cabbage worm control tips I mention will work just as well for cabbage loopers and diamond back moth caterpillars too.
What Are Imported Cabbage Worms?
Imported cabbage worms are common pests of plants in the brassicacea family, and they can be very destructive. They are the larvae of a butterfly called “cabbage whites”, “cabbage white butterfly”, or “small whites”.
They get their common name, “cabbage worm”, because they prefer eating crops in the cabbage family. Cruciferous vegetables are their main host plant.
What Do Cabbage Worms Look Like?
Cabbage worms are small, green caterpillars that start out tiny, and grow to be about an inch long. They’re soft green in color, covered in tiny hairs, and have a faint yellow line running down their back and sides.
They have legs all along their body, so their bodies stay flat when they crawl. If the green caterpillars on your cole crops bend their backs up when they crawl, then those are cabbage loopers instead.
In their adult form, cabbage worms are small white moths with a wingspan of only about 1.5 – 2 inches. They have a couple of black or brown spots on the wings, and can also appear to be pale yellow or light tan in color.
Cabbage Worm Life Cycle
Understanding their life cycle is important to help you get rid of cabbage worms. They hibernate through the winter as pupae, and emerge as adults in the spring. Shortly after emerging, the female butterfly will start laying her eggs.
Cabbage worm butterflies look harmless, and they are. In fact, they actually look really beautiful as they flutter and float around the garden. However, once you realize why they’re fluttering around (they’re laying eggs), they don’t look so pretty anymore.
Adult females lay their eggs on the undersides of leaves and, after a few days, tiny baby caterpillars emerge to start feeding on the plant. Cabbage worm eggs can be white, yellow or even green, and are so tiny they’re barely visible to the naked eye.
After about 3 to 4 weeks, once the caterpillars are full-sized, they will stop feeding to pupate. At this point, cabbage worms form cocoons (called a chrysalid) on the undersides of leaves. New adults will emerge from the chrysalis in about 10 days. There can be multiple generations in one season.
Where Do Cabbage Worms Come From?
Since the adults can fly, cabbage worms could come from anywhere. They are naturally attracted to cole crops, since that’s their main host plant.
So, if cabbage white butterflies are present in your area of the world, and you’re growing cruciferous veggies, then it’s a sure bet they’ll find your garden.
What Do Cabbage Worm Caterpillars Eat?
The main host plant for cabbage white butterflies are plants in the brassicaceae family. So, you can find the caterpillars feeding on any type of cruciferous vegetable plant.
Examples of popular crucifers are cabbage, mustard greens, bok choy, kohlrabi, brussels sprouts, kale, cauliflower, broccoli, turnips, radishes, and collard greens.
But, they can feed on other plants too. It’s not uncommon to find cabbage worms on other types of vegetables, and sometimes even flowers (they love my nasturtiums).
What Does Cabbage Worm Damage Look Like?
The first signs of damage you’ll probably notice will be holes in cabbage plant leaves (or kale, broccoli, cauliflower…etc). Cabbage worms eat uniform holes in the leaves between the veins and stems.
At their worst, they can completely skeletonize the leaves. Large populations can defoliate a plant very quickly, especially seedlings and small plants.
Unfortunately, they can also feed on the heads of cole crops like cabbage, cauliflower, brussels sprouts or broccoli too. The caterpillars will sometimes even bore into the heads, causing major damage to your crops.
How To Get Rid Of Cabbage Worms Naturally
Established plants can withstand some cabbage worm damage without worry. But the caterpillar population can grow very quickly, and will begin causing severe damage to plants.
When plants are severely damaged, it can stunt their growth, and they may not produce a head. Plus, leafy harvests will be destroyed. So, once you start seeing holes in the leaves, you’ll want to take swift action to get rid of cabbage worms.
The great news is that there are several organic methods you can use for controlling cabbage worms. So you won’t have to worry about using any toxic chemical pesticides on your vegetables.
Methods For Controlling Cabbage Worms Organically
Below I will talk in detail about the most effective natural methods for controlling cabbage worms. Keep in mind that it will take more than one treatment to get them under control, so it’s important to be persistent.
By the way, these methods also work for getting rid of cabbage loopers and the diamondback moth larvae too. So, you can use them no matter which type of caterpillar is eating your crucifers. Here’s how to get rid of cabbage worms naturally…
Related Post: Natural Garden Pest Control Remedies And Recipes
Hand Pick The Caterpillars Off Plants
One of the best, most natural ways for treating cabbage worms on your plants is to hand pick them. This sounds like a lot of work, and it can be at first. But if you’re diligent, the problem will go away pretty quickly.
They are really good at camouflage. They’re almost the same color, and tend to feed on the undersides of the leaves. So it can be difficult to spot them at first – especially when they are tiny baby caterpillars.
You’ll probably see their frass (aka poop) before you find the caterpillars. Cabbage worm poop looks like green sawdust or small green balls near the holes in a plant, or on the leaves below. Flip the holy leaf over, and you’ll likely find the culprit(s).
They don’t bite or sting, so you can pick them off with your bare hands. But if that grosses you out, then wear gloves. You should also pick off any eggs or cocoons that you find while you’re hunting for the caterpillars.
To kill cabbage worms, simply drop them into a bucket of soapy water. They can’t swim, and will eventually drown in the water. But the soap will kill them much faster. Of course you can always just smush them rather than bothering with soapy water, if you aren’t too squeamish.
Spray Neem Oil To Get Rid Of Cabbage Worms
Neem oil is a naturally occurring pesticide that kills caterpillars when they feed on the leaves, and it’s safe to use on vegetables. It has a residual effect too, which means you don’t have to spray your plants every day.
It doesn’t kill cabbage worms instantly, it takes a while for neem oil to get into their systems and kill them. Adding a mild liquid soap to the mix will help kill them faster.
Try Bacillus Thuringiensis (BT) To Treat Caterpillars
Bacillus thuringiensis (BT) is a naturally occurring soil-dwelling bacterium commonly used as a biological insecticide. BT works great for getting rid of cabbage worms, cabbage loopers, and any other caterpillars that feed on plants.
Simply spray it on the leaves of infested plants. When the caterpillars eat it, they’ll stop feeding right away. Though it can take a few days for them to die.
Use Insecticidal Soap Spray To Kill Cabbage Worms
Insecticidal soap will kill caterpillars on contact. So this is a good alternative if you’re too squimish to hand pick them. It only works when you spray it directly on the cabbage worms, and has no residual effect.
Spray the leaves as soon as you start seeing damage, the soap will destroy both the eggs and the tiny caterpillars. Be sure to spray under the leaves too, since this is usually where they’re hiding.
How To Prevent Cabbage Worms
One of the most effective ways to get rid of cabbage worms on your plants is to prevent them in the first place. So this section is for you if you want to learn how to keep worms off cabbage plants…
Use Row Covers To Prevent Cabbage Worms
Since brassicas don’t need to be pollinated by bees, floating row covers are an excellent way to prevent cabbage worm infestations. You can cover the crops right after planting, and leave the covers on all summer long.
Row covers will keep cabbage worm butterflies from laying their eggs in the first place. So be sure to cover your crops as soon as you plant them, before the butterflies can get to them.
But don’t worry if you don’t get the covers installed right away, you can add them at any time. Just keep an eye on the plants after you cover them. Once you get rid of cabbage worms already on the plants, the covers will keep new ones off.
Since they are lightweight, floating row covers allow plenty of sunlight and water through, so the plants will grow just fine. Simply adjust them as necessary to allow plenty of room for your plants as they grow larger.
Attract Beneficial Predators To Control Cabbage Worms
Beneficial bugs, like wasps, ladybugs, spiders, ground beetles, and praying mantis are excellent cabbage worm predators. So plant flowers to attract these types of predatory insects to help in your fight.
Birds also love eating caterpillars like cabbage worms, and they can eat a lot of them! So be sure to make your garden bird-friendly too.
Destroy Cabbage Worm Pupae In The Fall
As I mentioned above, cabbage worms overwinter in their pupa stage, and they hibernate in plant debris or the soil. So there are a few things you can do in the fall to help get rid of cabbage worms…
- Remove all of the dead plant material, especially anything in the cabbage family. Be sure to destroy it, or throw it into the trash, rather than putting it into your compost bin. Otherwise, the pupae can just overwinter in there.
- After cleaning out your garden in the fall, till or turn the soil. This will help control cabbage worms by destroying the pupae, or expose them so that predators can eat them.
Cabbage Worm Control FAQs
In this section, I will answer the most frequently asked questions about controlling cabbage worms. After reading through the post and FAQs, if you have any other questions, please ask them in the comments below. I will get them answered them as soon as I can.
How do you get rid of worms in cabbage before cooking?
To get rid of cabbage worms before cooking, you can simply soak the leaves or heads in water for 5-10 minutes. The caterpillars will drown, and sink to the bottom.
Be sure to completely submerge everything so the caterpillars can’t crawl on top, or into air pockets and hide. You’ll also probably need to weigh things down, since the leaves and heads will float. I use a heavy plate or bowl to keep everything submerged.
How do you kill cabbage worms?
If you’re too squeamish to squish them after hand picking, I don’t blame you! So instead, you can kill cabbage worms by dropping them into a bucket of soapy water, or spray them with insecticidal soap.
What eats cabbage worms?
Birds love eating cabbage worms and other caterpillars. Predatory insects like spiders, wasps, ground beetles, and ladybugs will also eat them. Attracting these natural predators can make it much easier to control cabbage worms.
What can I spray on my cabbage plants to keep bugs off?
Does baking soda and/or flour work to kill cabbage worms?
That’s debatable. I have heard people share that they use a 50/50 mix of four and baking soda to get rid of cabbage worms. The caterpillars are supposed to eat it, and then die few days later.
I have never tried it myself, so I can’t speak from experience. But there’s not much info out there about this method, so I’m leary of it. It would be an inexpensive experiment if you want to give it a try though.
Are cabbage worms poisonous?
No. As disgusting as it would be to know that you accidentally ate a cabbage worm, they are not poisonous or harmful if eaten. Think of it as added protein.
Getting rid of cabbage worms in your garden can be very frustrating. It may take a little bit of trial and error to figure out what works best for controlling cabbage worms. But if you are diligent with your treatments, your problem will go away pretty quickly.
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Share your tips and methods for getting rid of cabbage worms in the comments section below.