Ten Methods for Dealing With Cabbage Worms

Some people think cabbage moths are butterflies and they’re sexy. They’re not sexy. They’re assholes.”

Ron Finley

Cabbage moths are kind of pretty…unfortunately they’re pretty destructive too! When you see them fluttering around your brassicas (cabbage, broccoli, Brussels sprouts, kohlrabi and others) it can send you into a flap. I love wildlife–including insects–but I don’t like to eat them. Cabbage moths love to lay their larvae on the leaves of brassicas and when the larvae hatches into worms those worms love to eat their way through your brassica patch. All that love can leave a hole in your brassica leaves!

Here are 10 tips for thwarting the moth and its wiggly green offspring…

Tip 1 – Get Shaking! Zip down your rows with a salt shaker in hand and lightly dust your plants with salt. Don’t go too crazy or you could damage the plants. The larvae is super sensitive to salt and will expire in a day or two. Reapply once every two weeks or after a rain.

Tip 2 – Spray it! If you are nervous about overdoing it with the salt shaker you can choose to spray it rather than sprinkle. Simply mix 2 tbsp. (30 ml) of salt with 1 gallon (4 litres) of water, pour into a clean spray bottle and mist your plants. Do this in the evening or on a cloudy day to avoid any leaf burn. Once again reapply every two weeks or after a rain.

Tip 3 – Handpick. While this method isn’t for the squeamish, it is very effective. Grab a coffee can or similar container, lift the leaves and pick off the worms. What you do next is up to you. Some people feed them to their chickens, others fill the coffee can with water and drown them and still others pack them off and set them free. Though if you choose the latter method just keep in mind that it could come back to bite you in the brassicas. Whatever you choose, please be humane about it. Don’t leave the worms to die a slow death in the can.

Tip 4 – Go undercover. Thwart the cabbage moths right from the start by covering your rows with a floating row cover.

Tip 5 – Find some friends! Companion planting is another popular method. Intersperse your brassicas with onions, garlic, dill or rosemary (all repel cabbage moths) and geraniums (traps cabbage worms). A huge patch of brassicas provides an easy to find feast, while mixing your plants up confuses the moths.

Tip 6 – Cover your head! If you have your brassicas scattered here and there rather than all together you can use old nylons or small squares of reemay and elastic bands to individually cover the heads of broccoli, cauliflower, cabbage etc. Make sure you leave extra fabric so the vegetable can grow. Nylon works great since it naturally expands. Whatever material you choose make sure it is porous and allows light to get through.

Tip 7 – Transplant early…or late. Keep track of when cabbage moths congregate and you can start brassicas in advance so their harvest occurs before the moths arrive, or stagger your plantings so you harvest later when the moths have left for the season.

Tip 8 – Hot and Cold. If it’s too late and your produce is plumbed with worms, all is not lost. The most popular solution is to soak the infested produce in salt water for an hour. The worms should succumb and float to the top. Others recommend putting the vegetables in your fridge for a couple hours and then taking them out. The worms will crawl from the cold towards the warmth leaving the vegetables behind. Of course, this means you now have worms crawling across your counter. You could set them outside on a picnic table for half an hour or so instead.

Tip 9 – Chemicals…sort of. Bacillus Thuringiensis, commonly known as Bt is an organic method for getting rid of cabbage worms. It is safe to use right up until a couple days before harvest. Bt occurs naturally in the soil but has been isolated for use as insect control. It works by messing up the digestive system of immature larvae causing them to die from hunger or infection. Not much nicer than leaving them to die in a can, really. But it is safe to use around pets, birds and children.

Tip 10 – Don’t worry be happy. Welcome the addition of protein to your vegetables or simply pick out the worms. In a lot of countries worms, grasshoppers, ants and other insects are welcome additions to the dinner plate.