Recent studies have shown rototilling kills off 90% of the larvae in the soil. The larva of cabbage loopers is what’s referred to as cabbage looper caterpillar.

Because the insect overwinters in the soil, you could rototill the soil and provide some level of control of these pests as well. The cabbage looper also attacks carnations, nasturtium, lettuce, spinach, beets, parsley, potatoes and tomatoes. Next season when you get ready to plant, mix either dill weed, mints, wormwood or marigolds in with your tomatoes, which is not liked at all by the caterpillar. The only challenge is you kill them if they soap comes in direct contact with the compound. This also is a source of control for a gardener. Adult stages of hornworms are known as sphinx, hawk, or hummingbird moths. Although the tomato hornworm damages garden plants, most hornworm species cause insignificant plant injury.

Bacillus theringensis is a fungus that changes an insect’s blood from a clear substance to milky in color, hence milky spore disease. Hornworms are among the largest caterpillars found in Colorado. The tiny parasitic braconid wasp I discovered is another method of controlling the tomato hornworm as well as the lady bug and the lacewing insects.

As a side note, these are sphinx-type moths are related to the catalpa moth. Your first round of protection is to pull them off the plants as quickly as you can and put them in soapy water.

Download hornworm caterpillar