Someone’s eating my plants, and it’s not me!
Have you noticed big pieces of your plants missing? Those holes are likely evidence of cabbage white butterfly larvae, who love to munch on plants in the brassica family, including kale, collard greens, cabbage, broccoli and cauliflower. The fuzzy green worms blend in with the leaves, and can range in size from 1/4″ when they are very young, to over an inch long!
They’re usually on the tops of leaves during the day, and are often resting on the leaf “vein”, where they blend in best. The most reliable method for keeping them from eating your plants is to pick them off by hand, and then place in a bag that gets sealed and discarded. You can also squish them on site! To prevent them from getting on your plants in the first place, you can drape a floating row cover- which is a lightweight specialty fabric- over the bed. You can also try inter-planting strong-smelling herbs and edible flowers, such as dill, fennel and basil near your plants, to help repel the adult cabbage white butterflies so they don’t lay eggs on your plants.
Be sure to check under the leaves for their eggs and remove those as well. Don’t confuse frass, or poop, for the eggs or you won’t be making much of a dent in the population on your plants! You can also look out for chrysalises- the pupal form, under the leaves. Although it may seem harsh, it’s also a good idea to destroy these as well. When the pupa emerges as a cabbage white butterfly, it can lay large numbers of eggs, which will continue the cycle of eating plants in your garden!
I used to get a few cabbage butterfly worms in my garden every year, but this year I planted fennel next to my plants, and haven’t seen a single worm! I might be lucky, or maybe the fennel is working!
I used home-made insecticidal soap spray on mine and it worked great! Here is the recipe:
Soap has been used for centuries as an all-purpose pesticide. It disrupts insects’ cell membranes, and kills pests by dehydration. The key is not to use too much soap, or you’ll also kill the vegetation near the pests. If you follow the proportions of soap to water in the Soap Spray recipe, below, the vegetation should be fine. If your solution looks foamy when sprayed, you have too much soap in it.
1 to 2 tablespoons garden safe soap (not detergent)
1 quart water
Combine ingredients in a bucket, mix, then transfer to a spray bottle as needed.
How do you know if a soap is garden safe? Are there specific brands you recommend?
Hi Leone,
Liquid soap is garden-safe when it breaks down in the environment after a week or two, leaving no residue that may disturb insects or microorganisms. Oe good product is Safer Insect Killing Soap Concentrate, which is mixed with water before applied to plants. You can also use some brands that you might already have in your home, such as Dr. Bronner’s or plain Ivory.