The Artstor website will be retired on Aug 1st. The Florida Entomologist Vol. 65, No. 4, Dec., 1982 Feeding on Non-Host Plants by the Tobacc... Feeding on Non-Host Plants by the Tobacco Hornworm ...

“If you spot a hornworm on your tomato plant, my recommendation would be to promptly remove them by hand,” says Kantor. Seeing one of these caterpillars usually means there are several.