| Tomato hornworms are large, white-striped, green caterpillars. They are the larvae of a couple types of moth, including the pretty white-lined sphinx moth, which you may notice feeding at lantana and other flowers at dusk. It's the size of a thumb, with a cigar shaped body and is sometimes mistaken for a hummingbird in the low light! They caterpillars are large enough that you can just pick them off the plants and destroy them. If you notice they have little rows of white cocoons on their backs, leave them alone - that means a parasitic wasp has laid her eggs there. The eggs will hatch and the larvae will burrow down into the caterpillar and consume it from the inside out. You can spray or dust your tomato plants with the botanical insecticide called Bt. (Bacillus thuringiensis) to kill the hornworms. Bt is a stomach poison so expect that the pests will continue to feed until the bacterium takes effect. |
