May 3, 2012
Imported cabbageworm
Photo by Jessica Walliser
This year I’m combatting the cabbageworm, a garden pest that torments my cole crops, by cover the plants with floating row covers.

I have been busy hauling compost like a fiend these days! I line the back of my Subaru with plastic and fill it up with the leaf compost that our municipality gives away for free every spring. I must have slogged at least a dozen loads so far this season. And I have many more to go. It pays off in the end, though, in reduced weedsreduced watering and increased soil fertility.

Right now I am in the process of preparing my garden beds for vegetable planting. Within the next two weeks, it will be time for the warm season crops to go in and I am way behind on the prep work for their arrival. I still need to hammer in the tomato stakes, spread the compost in the beds, sort through my bucketful of cucumber seed packets, and mulch the paths with straw. Always lots to do!

One thing I know I am NOT going to do this year is let the cabbageworms get the best of me. Imported cabbageworms are common all across the U.S. They were introduced from Europe in the 1800s, and the caterpillars love to chew ragged holes in the leaves and flower buds of all members of the brassica family. I find them on my broccoli heads, kale, cabbagekohlrabi and cauliflower every year.

The cabbageworm caterpillars are 1 inch long at maturity and have fine velvety hairs on their body surface. They also have a faint yellow stripe down the sides of their light-green bodies. The adult butterflies (often called cabbage moths) have a 1- to 2-inch wingspan and are white to soft yellow with up to four black dots on their wings. They overwinter as pupae underground and emerge as adults in the spring.

I always spot their damage and their poop before I actually see the caterpillars. The poop (called frass) looks like dark pellets, and the ragged holes are not surrounded by slime trails, which would instead indicate night-time feeding by slugs. When cabbageworms are small, they are difficult to spot, so I always check the leaf undersides as well as along the leaf veins and crush any that I find.

To keep them from making a meal of my cole crops this year, I have covered all susceptible plants with floating row cover the day they were planted. Because these crops don’t need pollination, I will leave the row cover in place until I harvest them. Although I’ve never tried it myself, I have been told that sprinkling infested plants with corn meal will cause any cabbageworms that consume it to bloat and die.

And just incase some of the cabbageworms make it onto my broccoli heads, I always soak them in a sink of warm salt water before cooking them. Any cabbage worms on it will die and float to the top, keeping them out of the cooking pot and off of my plate!

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