How to Get Rid of Cabbage Worms - Backyard Boss
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How to Get Rid of Cabbage Worms

Holey cabbage leaves might be seen as truly organic offerings in some European countries, but chances are they’re not to your taste as a gardener. Cabbage worms are the culprits behind those small or large holes. But don’t let the name fool you.

It’s not just cabbage that these larvae of the Cabbage Moth and Cabbage White Butterfly crave. They devour anything from the brassica family, including mustard greens, broccoli, and collard greens. Fortunately, you have several options to get rid of cabbage worms, including humane methods that won’t leave you feeling too grubby.

WHAT YOU NEED

  • A pair of gloves
  • Pliers or tongs
  • Dish or liquid bath soap
  • Bucket of water
  • Floating row cover
  • Garden hoops (optional)
  • Eggshells or fish bones
  • A nest box
  • Small twigs
  • Dryer lint
  • Birdbath
  • Companion plants (like thyme, rosemary, or peppermint)
  • Spoon or large empty salt shaker (optional)
  • Fine cornmeal
  • Watering can or garden hose
  • Neem oil ready-to-use spray

STEP ONE: MANUALLY REMOVE CABBAGE WORMS

Cabbage worm on green kale leaf
Image credit: OSU Master Gardener via Openverse

Picking cabbage worms off of leaves is the quickest and easiest way to eliminate these critters. If you’re squeamish about touching them with bare hands, don a pair of garden or plastic gloves. You could also use pliers or tongs.

Prepare a bucket or container of water with dish soap. Cabbage worms move slowly, so you won’t have much trouble removing them once you spot them.

Once you have them in your grips, drop them into the bucket of water with the dish or liquid bath soap. The soap helps to kill them more quickly rather than just letting them drown. Still drastic, but a bit more humane.

STEP TWO: INSTALL ROW COVERS

Lawn covers for pest control
Image credit: Rachel Ford James via Openverse

The best way to get rid of cabbage worms is to keep them away from your crops in the first place. Row covers — which you might already be using to protect seeds and young plants — prevent Cabbage Moths and Cabbage Whites from laying their larvae.

When you cut the row cover, add a few extra inches so you can drape it loosely over the beds. Secure with nails, stakes of wood, or weighty rocks. If you prefer to not have the floating row cover rest directly on the plants, install gardening hoops over the beds, spaced a few feet apart. Then drape the row cover over the hoops. Secure it the same way as above.

Brassica family doesn’t need to pollinate so it is no problem to leave these breathable covers on.

STEP THREE: ATTRACT MORE TREE SWALLOWS

Tree swallow on a wood
Image credit: Ania Tuzel Photography via Openverse

If you live in the upper half of the country, you are lucky to have a predator around that can protect your garden greens. Tree swallows love to feast on all kinds of insects, but the cabbage moth is a favorite. When these birds scare away or prey on the parent bug, you won’t see as many cabbage worms in your crops, if any.

Tree swallows need calcium during the breeding season. Rinse off eggshells or fish bones and scatter them in open spaces (close to those veggie beds, perhaps) in your garden.

Installing a nesting box, complete with twigs and dryer lint, will attract tree swallows as well. Also, birds are attracted to water for drinking and bathing, so place a bird bath in your garden. It could be as simple as a kiddie pool filled with water.

STEP FOUR: ADD COMPANION PLANTS

Herb Garden - Thyme on the Rocks
Image credits: 2ndLookGraphics via Canva

Cole crops — another term for the brassica siblings — can also find protection from a few companion plants. Members of the mint family, including rosemary, peppermint, and thyme, will help to deter cabbage worms. So too does borage, which is making a comeback, especially with ornamental gardeners.

Best of all, the brassica buddies complement each other very well when you’re cooking. Or you can use them for meat dishes, sauces, and healing herbal tinctures and teas. However, it’s best to grow mint in pots because they love to take over any open space in which they are planted.

STEP FIVE: FEED CABBAGE WORMS CORNMEAL

watering vegetables
Image credits: preechafakmee via Canva

Cornmeal is a really accessible and fuss-free way to get rid of cabbage worms. You could just use your hand or a spoon to powder the plants with the cornmeal. But there is a neater way.

Add some fine cornmeal to an empty salt shaker. Using a garden hose or watering can spray the leaves of your vegetable plants with water.

Next, grab the shaker and dust a light layer of cornmeal over the leaves of the plants. Cabbage worms will snack on the cornmeal, bloat, and pass away. At least they enjoyed a delicious last meal.

STEP SIX: KEEP THEM AT BAY WITH NEEM OIL SPRAY

spraying the garden
Image Source: Oregon State University via Creative Commons

Neem oil comes from the neem tree, a member of the mahogany family Meliaceae. The oil has become a popular choice for natural or organic pest control. Rather than killing cabbage worms, however, neem oil will deter them with its garlicky or sulfuric scent.

Another benefit of neem oil is it won’t endanger beneficial insects in your garden and there’s no sticky residue. But because it degrades speedily, you’ll need to reapply it more often than non-organic pesticides.

For the simplest application, purchase neem oil as a ready-to-use spray. If you buy the concentrate, dilute it with water and dish soap. A typical ratio for the mixture is 1.5 teaspoons per 1 quart of water, plus 0.5 teaspoon of soap (as an emulsifier).

CABBAGE WORMS MAKE TASTY MEALS, FOR SOME

chicken garden
Image credits: Canetti via Canva

If you have chickens in your backyard, there’s an even more humane and sustainable way of disposing of cabbage worms. Allow them to be part of the food chain by feeding them to your hungry birds.

IN SUMMARY

Follow these tips on how to rid your garden of cabbage worms. While removing them by hand may not be the first option for every gardener, there are multiple options to keep your plants safe while removing this nuisance.

Also, it seems that red and purple versions of your favorite greens might be self-protective against cabbage worms. A USDA study showed that these caterpillars grew less, and eventually died at higher rates after feeding on isolated anthocyanins, a group of flavonoids that give plants their red, blue, and purple colors.

Willing to try it? Let us know if you notice a difference.

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