Recent studies have shown rototilling kills off 90% of the larvae in the soil. Because the insect overwinters in the soil, you could rototill the soil and provide some level of control of these pests as well. 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.

On the bottom is a link and relevant quote. This also is a source of control for a gardener. The tobacco hornworm (Manducta sexta) needs soil or leaf litter to pupate. Bacillus theringensis is a fungus that changes an insect’s blood from a clear substance to milky in color, hence milky spore disease. 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. If you spy these whirring moths hanging in mid-air and sipping nectar from flowers in your garden (usually at dusk or later), you need to keep an eye out for hornworm caterpillars. As a side note, these are sphinx-type moths are related to the catalpa moth. Hornworm caterpillars are the larvae of the hummingbird (or sphinx) moth, which gets its name from its fast wing speed. Your first round of protection is to pull them off the plants as quickly as you can and put them in soapy water.

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