Cabbage loopers are the larvae of nocturnal brown moths. These caterpillars have smooth, light green skin emblazoned with thin white racing stripes. Loopers reach a length of up to 1.5 inches, and move by arching their bodies while crawling. They feed on vegetable plants in the cole family, including cabbage, broccoli, kale and cauliflower. The little beasts not only chew holes in the plants, but add insult to injury by leaving slimy green excrement behind. Fight back with some simple solutions that won’t harm your family or the environment.
Plant your vegetable as early as possible. This may give your plants a big enough head start with development that you’ll be able to harvest before cabbage looper damage becomes problematic.
Narrow cabbage looper menu choices by keeping your planting site and nearby areas well weeded. Weeds such as wild peppergrass, mustard and shepherd’s purse attract these pests.
Exclude cabbage loopers by protecting plants with horticultural fabric or row covers.
Pick cabbage loopers from your plants by hand and squash them. If you don’t like squashing, drop them into a pail of soapy water. Loopers are large enough to see if you examine plants carefully, even though their coloring does offer them some camouflage benefits.
Cut the legs of an old pair of pantyhose off at the knees if you don‘t have or don’t wish to pay for row covers. Slip the ankle and foot portion over the developing head of cabbage to form an enveloping cover that loopers can’t penetrate. The stretchy material gives as the plant grows, so you can leave it in place until you’re ready to harvest.
Dust weekly with Bacillus thuringiensis, commonly referred to as Bt. This naturally occurring bacteria destroys cabbage loopers quite efficiently.
Clean up and dispose of plant material and debris from infested areas following harvest. Cabbage loopers may over-winter in old foliage, so don’t add it to your compost heap.