How to Get Rid of Cabbage Worms in the Garden

The cabbage white butterfly is drawn to brassicas (cabbage, cauliflower, broccoli, bok choy, kale…). A single caterpillar can decimate a young plant. Here’s how to get rid of cabbage worms in your garden — naturally.

Check out these natural methods for controlling some other garden pests, too!

cabbage white butterfly on a pink zinnia
Once upon a time, when I was a little girl, I proudly showed my grandma a wee sweet caterpillar. Instead of oohing and aahing over my find, Grandma snatched the wooly thing out of my hand and smashed it under foot. To her, it was simply a garden pest, but I was crushed.

I like to think that I’d never do such a thing in front of a child, but I can and do handpick pests in the privacy of my own garden. Cabbage whites – those pretty white butterflies that flit around home gardens in the summertime – can wreak havoc in a garden.

The other day a cabbage moth flew by. I did the logical thing and snatched it out of the air. There were no witnesses to my cruelty or to the fact that I’d snatched a moth right out of the air. I have turned into my Grandma, albeit a ninja version of my grandma.


 

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Identifying cabbage worms

There are a number of green worms that can plague cabbage and other brassica plants.

  • Cabbage loopers are the larval stage of a grayish-brown moth. This worm has legs toward the front and the back of its body, but none in the middle. It moves in a characteristically “inchworm” style.
  • The larval stage of the diamondback moth is much smaller than the cabbage looper or the cabbage moth, at about 5/16″ long.
  • The cabbage worm is the larval stage of a cabbage white butterfly.

There are some similarities between the different pests. The adults flock to plants in the cabbage family, brassicas like collards, cabbage, cauliflower, broccoli, bok choy, and kale, making it difficult to get these plants established in a garden. A single caterpillar can decimate an entire young plant, making them some of the most frustrating garden pests to deal with.

Let’s focus on the one cleverly named “cabbage worm.”

Cabbage worm eggs

Cabbage moths are to brassicas as hornworms are to tomatoes. They are THE pest that you need to know about if you plan to grow brassicas.

White cabbage butterflies lay their eggs on brassica plants, often on the underside of the leaves. They are initially white, but turn yellow as they mature. The tiny eggs hatch in about seven days.

cabbage worm eggs on a kale leaf

Cabbage white larvae

Tiny cabbage worms emerge from the eggs and begin immediately chewing on the leaves. The first telltale signs of damage will be shallow, grayish markings in the leaves. At this stage, the worms aren’t big enough to chomp all the way through a leaf. Not to worry, though — it will happen quickly enough!

Cabbage worms are a lovely velvety green. They blend in easily in a bed of green plants.

cabbage butterfly larvae on a kale leaf

These worms tend to hide on or near the veins of leaves. When they’ve reached maturity at about an inch or 1-1/4″ long, they’ll pupate in preparation for their transformation into a cabbage white butterfly.

The chrysalis is often attached to the host plant or in nearby debris. In this case, it has attached itself to the planter my kale is growing in.

cabbage butterfly chrysalis

How to prevent cabbage white butterflies from moving in

An infestation of these pests can wipe out a young crop of cabbage or kale in days. Prevention is the best way to avoid that loss. There are a number of natural tactics you can use to prevent these pests from taking up residence.

  • A floating row cover can prevent cabbage moths from accessing leaves on which to lay eggs, thus breaking the cycle. Another idea is to cover individual plants with upcycled mesh trash cans.
  • Consider planting some cabbage moth trap plants to draw the cabbage worms away from your vegetable garden. A good choice in this case is a perennial tree collard. Planted some distance from your garden, you can let the moths go to town on these “sacrificial” plants.
  • Interplanting brassicas with dill and lavender can deter cabbage butterflies. More on companion planting here.
  • Give plants a good dusting of diatomaceous earth on a regular basis. Even if a butterfly manages to lay eggs on the plants, the soft-bodied caterpillars won’t stand a chance.

damaged leaf with caterpillar

Signs that you have a cabbage worm problem

If you begin to see cabbage white butterflies flitting around your garden, it’s time to start watching your brassica plants for signs of the dreaded cabbage worm.

First though, grab an old tennis or badminton racket. It may seem gruesome, but I’ve had good luck swatting these flying pests out of the air. Killing them at this stage prevents them from laying eggs and interrupts their life cycle.

One of the best tactics for preventing cabbage worms is to check plants every few days for eggs and caterpillars. The earliest sign — and a chance to stop damage completely — are those tiny eggs. Check the underside of the leaves and wipe the eggs off.

Also look on the under side of the leaves and in leaf veins for tiny (TINY) green caterpillars and wipe those off as well.

cabbage moth poop on a kale leaf

Early damage will be hard to spot, but as the worms grow bigger, it will become more obvious. Chewed up leaves are a sure sign that you have a problem, but you might also notice tiny black droppings indicating that a cabbage moth has been eating (and pooping) on your plants.

Check the central vein of the leaves where it’s easy to miss the caterpillars. Giving the plants a good shake can dislodge cabbage worms, causing them to fall to the ground, but this isn’t a surefire method, as some will hang on tighter than others.

caterpillar hiding on a stem of kale

Instead of removing the chewed, ugly old leaves from the plants, try leaving them intact as bait for the cabbage moths. I’d rather have the caterpillars chewing on those than the young leaves.

WHITE BUTTERFLY on a thistle flower

 
Sources for more info:
  • https://entomology.ca.uky.edu/ef300
  • http://entnemdept.ufl.edu/creatures/veg/leaf/imported_cabbageworm.htm

Originally published in May, 2012.

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About the author: Kris Bordessa is an award-winning National Geographic author and a certified Master Food Preserver. Read more about Kris and how she got started with this site here. If you want to send Kris a quick message, you can get in touch here.

34 comments… add one
  • Debbie Aug 19, 2022 @ 11:05

    I have raised garden boxes and a low hoop house over it. I have switched from plastic for early extension to fine netting (the kind used in making crinolines I get it from the fabric store). It has to be above the veggies bas if it touches the leaves the butterflies will just lathe eggs on it. Works well the sun shines through and the rain gets through. I like it better than row covers. I just lift up the side I am working on then clip it back down. You have to make sure that there is no space the butterflies can get under. They are sneaky little buggers!

    • AttainableSustainable Aug 23, 2022 @ 6:49

      That sounds like a good method!

  • Susan Dolan Jul 10, 2022 @ 6:49

    I hung string with long flash tape stripes attached across the cabbage, patch, and, so far, only one plant had a cabbage worm. I think the moths are scared away by the constant motion of the tape.

    • AttainableSustainable Jul 12, 2022 @ 6:00

      That’s a good method, I’m glad it worked!

  • Linda Bradley Aug 27, 2020 @ 6:50

    Do you leave the floating row cover on all summer?

    • Kris Bordessa Oct 26, 2020 @ 12:37

      As long as you need to protect the crop!

  • Alice Ro Jul 8, 2019 @ 3:38

    I use a lot of DE, I lay a carpet down under my plants. I mix it in water and spray it too. You can’t hurt a plant or yourself and don’t listen to people who say you can’t get this stuff wet, that’s wrong. This product makes the plants taste intense, try just one plant (tomato) and see for yourself. I do a lot of experimenting in my garden of cannabis. I also like bright, big twirly things, shiny is great, anything that spins helps. I grow companion plants in pots and move them to problem spots. Most bugs do not care for the mints. We are pretty biodynamic. I grow a lot of mulch.

  • Liz Hallengren Apr 8, 2019 @ 2:44

    I have tried sifting flour lightly over broccoli to work keeping moths away.

    • Kris Bordessa Apr 10, 2019 @ 7:48

      Interesting!

  • Mary Jo Mar 18, 2019 @ 8:53

    I found planting dill with brassica makes a difference. Dill attracts lacewing which seem to also like the cabbage worm.

  • Mark Starkweather Aug 22, 2018 @ 7:28

    BTk is a great organic remedy for any sort of caterpillar. One bite and the little bugger is immediately paralyzed. He might not die right away, but he’s not eating any more. During times of heavy infestation, spray once every three days, or again after it rains.

    This includes tomato hornworms.

  • Karen Finlayson Jan 8, 2018 @ 1:15

    Hi, all, I tried coriander /cilantro, worked till the heat sent the coriander /cilantro to seed, repurchased coriander /cilantro and am reattempting, will do my best to keep you all posted, may need a reminder via email, bye for now, I live in Nowra, NSW, Australia

  • William Owens Jan 3, 2018 @ 11:25

    I have had success with Dipel dust or BT. Its a biological deterrent. Must be applied again after a rain.

  • julia Aug 23, 2015 @ 2:18

    My excitement in showing my grandma a nest full of tiny little bunnies ended in much the same way as your caterpillar story. Shocking. Those ladies didn’t mess around when it came to the sanctity of their potential harvest. ‘Self-reliance’ was paramount.

    • Kris Bordessa Aug 23, 2015 @ 14:41

      Oh no! But yes, self-reliance *was paramount!

  • Earline Bradt Jun 26, 2015 @ 4:55

    I am companion planting with dill, I had one broccoli get damage before I planted the dill, no further damage since planting dill in between the broccoli plants. 🙂

  • Barbara Jul 5, 2014 @ 20:18

    I call those stinkers cabbage loopers .. Pesky!  I grew red cabbage & read a hint to use stockings – when the cabbage starts to form loosely tie a bonnet out of the hose to cover the head to the base – tie it, don’t choke it – it worked!! I was so tired & creeped out w those green things!! 

    • Kris Bordessa Jul 6, 2014 @ 11:12

      Great tip!

  • joostharmsen Aug 21, 2012 @ 23:47

    Hope the traps work!! let me know the result! 🙂

  • Alternative Eden Aug 1, 2012 @ 0:08

    Oops just realised to mistyped *good*, but good luck and even goof luck!! 🙂

  • Alternative Eden Aug 1, 2012 @ 0:06

    Goof luck hope the trap works!

  • JCreatureTravel Jun 26, 2012 @ 20:26

    I’m interested in your homemade trap. Hoping it works.

  • ruth pennebaker Jun 20, 2012 @ 9:57

    Grandmothers were made of tougher stuff back then. Thanks for the funny image of your childhood horror.

  • Alexandra Jun 19, 2012 @ 13:29

    This is so timely!  We have these again this year, in the veggie garden.  A couple years ago I got some living thing, parasite something is all I can remember, and it caused the cabbage moths to die.  I did not know about the yellow eggs.  Will go and check the leaves right now.

  • MyKidsEatSquid Jun 19, 2012 @ 4:49

    I’m interested in what sort of trap you’ll be setting up–sounds fascinating. This year, my garden will all be in pots. Small steps, one of these days I’ll try making a full garden again.

  • Jane Boursaw Jun 18, 2012 @ 15:04

    Well, those little moths really are so pretty, though I understand where your grandma was coming from. 

  • Lagene May 31, 2012 @ 11:50

    I have been puffing Diatamaceous Earth on mine and so far so good…..

    • Attainable Sustainable Jun 6, 2012 @ 14:04

       @Lagene I’ve had mixed success with DE on some of my other plants, but maybe it’s worth a try on this!

  • kelly May 30, 2012 @ 18:02

    I am fiI am fighting these as well.  I didn’t know what they were but I knew they are eating my Kale!  I go out every morning and pick off a few.  Now I know what to look for as far as the eggs and the adults.   I am interested in your trap.  Can’t wait til you share.

  • Harvest=food security (the photo album movement) May 30, 2012 @ 12:14

    I haven’t tested this yet, but I’ve heard that if you plant a white flowering plant amongst the brassicas the cabbage whites think that patch is already overpopulated with butterflies, thus there won’t be enough food for their caterpillars, so they keep flying. (Not saying it’s a conscious thinking choice on their side, but lots of white in a brassica patch will supposedly keep them at bay.)

  • Beverly Kisner Brown May 30, 2012 @ 11:23

    I have managed to make them go elsewhere by adding my leftover coffee to the water I water them with. I also put the coffee grounds around their bases. I do not know if it worked or if my brussel sprouts just tasted better.

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