The Q&A Archives: Tomato Hornworms

Question: Last year I had a season long problem by tomato cut worms that originate from a black moth, I believe. How do I prevent these pests this year without having to drown the plants with Sevin? Thanks!
Sarah Hansen

Answer: Tomato hornworms can be 4-5 inches long at maturity, and seeing them can be quite a shock! Hornworms are the larvae of a large moth (Manduca, with a wingspan of 3 1/2 - 4 1/2 inches). The adult is attracted to tomatoes, eggplant, peppers, potatoes, dill, and various weeds. She lays her eggs on the host plant, the eggs hatch, and the larvae feed and feed. They have voracious appetities and can denude a tomato plant in a day! Handpicking is the best defense. You can use the botanical Bt (Bacillus Thuringiensis), which is a bacterium that acts as a stomach poison, and is quite effective against most caterpillars. It is sold under several brand names, including Dipel. To keep hornworms away from your tomato plants next year, try interplanting with dill. (Hornworms like dill and are easier to see and remove on the wispy dill foliage.)

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