Oh there’s a beautiful white butterfly!
Said no gardener who knows the cabbage moth
Cabbage worms can wreak havoc on your cabbage plants and other members of the cabbage family. These include cabbages, broccoli, cauliflower, kohl rabi, kale and brussel sprouts. That ‘beautiful white butterfly’ will be one of the first you see early in the springtime and is called a cabbage butterfly or moth. They lay tiny white eggs underneath your brassica leaves which become cabbage worms. Within days that tiny cabbage worm will become a large one consuming large amounts of your homegrown produce and leaving huge holes, not to mention yucky green stuff (cabbage worm excrement, gross). You can learn about the full life-cycle here.
Can you prevent cabbage worms? Deter them? Kill them?
This post will cover:
- Preventing cabbage worms
- Plants that help to deter them
- How to kill cabbage worms
- Parasitic insects that eat cabbage worms
Preventing Cabbage worms
There are a couple of ways for preventing cabbage worms on your brassicas/cole crops. One way is to locate the damaged plants (easily spotted with holes in them) and look over the plant. You can find and squish the caterpillars or give them to your chickens. You can also see clusters of eggs underneath the leaves, but because other bugs lay eggs, I wait until they’ve hatched to squish the tiny caterpillars. They often hide on the very inside part of the plant, so make sure you check it over thoroughly. Do these a couple of times a week in the spring, and again in the fall.
Spot the holes on damaged plants
Seek the tiny green (or large) green cabbage worms eating your plant
Cabbage Worms get large very quickly
Yuck. Once they get this big I use my garden boots
Killing them using Bt as a natural pesticide approved for organic growers.
What is it exactly? BT
Bt proteins has been used in many organic farms for over 50 years as a microbial pest control agent (MCPA). Bt proteins are allowed in organic farming as a insecticide because Bt is a natural, non-pathogenic bacterium that is found naturally in the soil.Bt has also been found to be safe to all higher animals tested.
read an interesting post on BT and it’s relation to BT GMO corn & organic growing
Plants that repel cabbage worms
There are some plants that repel cabbage worms. Onions, leeks and garlic for example repel them, however cabbage white butterflies and their damaging cabbage worms are very early in the season. I recommend overwintering onions or garlic so that there’s some scent deterrence early in the spring. You can also plant strong smelling herbs. Learn more organic pest control methods and plants here.
Row cover works great at preventing pests like cabbage worm from getting at your plants. It helps to have a watering system in place like drip irrigation however, because lifting up the tunnel to water might mean they sneak in!
Wasps get a bad rap but their stings hurt and they can be aggressive, but they also eat a lot of garden bugs. There’s even a predatory wasp that lays eggs inside the caterpillar (yuck right!?). It’s super gross, but they are great natural pest control for caterpillar worms. Learn more here.