Keeping the Caterpillars out of the Cabbage

Created on 5/15/2009

This is theoretically our last frost date according to the USDA charts, but I’m not buying it. We woke up to an inch of snow on the ground Wednesday morning, and our nighttime temperatures are still flirting with the low to mid-thirties. That’s not exactly my idea of a “safe” when it comes to planting my tender favorites. I have a flat of ‘Genovese’ basil, ‘Goliath’ sweet peppers and the Hungarian medium-hot block peppers that are an heirloom variety from my Dad’s farm. I’m not about to chance them even with protection and a forecast reaching over 80-degrees this weekend.

Thankfully, there are many other varieties I can put into the ground before the weather moderates. I need to finish planting onions, as well as seeding carrots, kale, kohlrabi and more lettuce to stagger the harvest. My cabbage – a mini type and one specifically for sauerkraut – and broccoli are planted and doing fine after days of high wind and nasty weather. Now I have to be proactive so I don’t harvest holey vegetables.

I love butterflies as a general rule, but when I see pretty little white ones flitting above my cabbage, broccoli or cauliflower I know I need to take action. The Small White Cabbage Butterfly is a common pest that lays its eggs on the underside of leaves. Once the eggs hatch, the larvae can do a tremendous amount of damage.

This is the same with the Cabbage Looper. You usually don’t see the butterfly since they’re nocturnal. The Loopers are the cute little inchworms that absolutely devastate cabbage heads, and add unwanted protein to broccoli and cauliflower dishes. I find them many times when I cut and blanch broccoli before I’m going to freeze… or serve… it. Yick. And I’ve lost heads of cabbage that looked absolutely perfect, but when I opened it up there were holes bored through it and feces squished in between leaves. Double yick.

There are a few ways to repel these unwanted pests. Since the Small White Cabbage Butterfly is usually seen in June in our area, I’ll soon cover my cabbage, broccoli and cauliflower with floating row covers to prevent them from laying eggs on the leaves. They’ll attack other varieties, such as kale, kohlrabi and beets, but these are the two crops that bother me the most. With loose leafed vegetables, I can see them easier to pick them off, but there are just too many places to hide with cabbage, broccoli and cauliflower.

Another option is to use Bt (Bacillus thuringiensis), a bacterial insecticide that kills the caterpillars after they feed on it. It’s usually applied to the leaves as a liquid and is considered an organic alternative.

Planting pungent herbs around the plants can help repel the butterflies, as well. Intersperse the vegetable garden with mint (plant it in a sunken five gallon bucket to keep it from becoming more of a problem than the Loopers!), rue, tansy, dill, lavender and sage. They’ll not only help keep the butterflies at bay, but they’ll smell great while you’re weeding.