How to Get Rid of Cabbage Worms

By: Angela Judd | November 26, 2024

Cabbage worms can be a real headache for gardeners. These tiny, green caterpillars love to munch on your precious plants, especially those in the brassica family, like cabbage, broccoli, and kale. If left unchecked, they can cause significant damage, particularly to young plants. But don’t worry—I’ve got some tried-and-true methods to help you get rid of cabbage worms and keep your garden healthy.

young brassicas with cabbage worm damage

Article Index:

Spotting Cabbage Worms
Natural Predators and Companion Planting
Handpicking Cabbage Worms: The Simplest Solution
Use Row Covers (But Do It Right!)
When to Use Bt (Bacillus thuringiensis)for Cabbage Worms
Tolerating Some Cabbage Worm Damage
Crops Most Susceptible to Cabbage Worms

Spotting Cabbage Worms

Cabbage worms are the larvae of the cabbage white butterfly, those small white moths you might see fluttering around your garden. The worms are usually green and can blend in with the leaves, making them tricky to spot.

The first sign of cabbage worms is often the damage they leave behind—holes chewed into the leaves of your plants. Take a closer look and flip the leaves over. You’re likely to find the culprits: small, green worms and possibly the tiny eggs of the cabbage moth. If you notice white or yellow moths fluttering around your garden, it’s a sign you should inspect your plants regularly.

Natural Predators and Companion Planting

One of the best ways to get rid of cabbage worms is to encourage biodiversity in your garden. Natural predators like birds or beneficial insects can help control cabbage worm populations. You can also plant companion plants that repel cabbage moths, such as thyme, dill, or nasturtiums. This isn’t a quick fix but a long-term solution to a healthier garden overall. Learn more about companion planting principles in this blog post.

Handpicking Cabbage Worms: The Simplest Solution

Handpicking is the easiest and most immediate way to control cabbage worms. Search for them on the undersides of leaves, where they tend to hide. While you’re at it, scrape off any eggs you see. It may feel tedious, but it’s highly effective, especially if you catch them early. Don’t let the worms get your kale–use it in this kale salad instead!

Get in the habit of spending time in your garden each day. Checking the leaves for worms is one of the things to add to your list of what to do in your garden each day. This small habit makes it simple to prevent big infestations.

Use Row Covers (But Do It Right!)

Row covers can create a barrier between your plants and cabbage moths, but they must be used correctly. Before installing them, ensure your plants are free of eggs and worms—otherwise, you’ll just be trapping pests inside. Be sure the covers are securely sealed around the edges so moths can’t sneak in. Get row covers here.

While row covers can work well, I’ve seen them backfire when they’re not applied carefully. In one case, I even saw a garden (mine–see pics below!) filled with trapped cabbage moths happily laying eggs under the cover!

When to Use Bt (Bacillus thuringiensis)for Cabbage Worms

If handpicking and row covers aren’t enough, consider using Bt (Bacillus thuringiensis), a naturally occurring bacteria that’s toxic to caterpillars but safe for humans, pets, and plants. Bt is an organic solution, but it should be used sparingly to minimize harm to other beneficial insects like butterflies and pollinators. Get Bt here.

Here’s how to use Bt effectively:

Follow the package instructions carefully for dilution rates.
Spray it directly on the affected plants, focusing on the inner leaves where new growth occurs.
Reapply every 10–14 days as needed.

Bt is a targeted solution, but it’s important to avoid spraying it all over your garden. While it’s organic, it still kills other caterpillars, so use it sparingly. To learn more about organic pest control that really works read this guide.

Tolerating Some Cabbage Worm Damage

Keep an eye on the inner new growth, if you see holes there, cabbage moths can cause severe damage to the developing plant and should be dealt with. As plants grow older, they can withstand more damage without significant impact. Outer leaves may have holes, but they protect the inner growth.

Crops Most Susceptible to Cabbage Worms

Cabbage worms love plants in the Brassica family, including:

If you’re growing any of these, keep an eye out for signs of damage and act quickly to prevent major infestations.

When you spend time in your garden each day, you’ll spot problems like cabbage worm infestations when they are small and easy to manage. By combining these methods—handpicking, row covers, and using Bt sparingly—you can get rid of cabbage worms effectively without damaging your garden’s ecosystem.