Canyon Country, CA
|I have those big green catapillers on some of my tomato plants this year. How do I kill them and prevent them from coming back?
|Answer from NGA
August 2, 1998
|Tomato hornworms are large, white-striped, green caterpillars. They're 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 allown - 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.
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