UCCE Master Gardeners of Orange County
University of California
UCCE Master Gardeners of Orange County

Weeds & Pests

Tomato Hornworms

tomato hornworm
Tomato hornworms are the larval (caterpillar) stage of the tomato hornworm moth. The moths are active at night and also lay eggs on plant leaves at night. The caterpillar eats (and eats) tomato leaves and tomato fruit, then burrows into the ground and pupates over the winter months in the soil. The adult moths emerge in spring.

The hornworm moth and its pupa are pictured.
Tomato hornworm moth
Tomato hornworm pupa

The best control method for tomato hornworms is to pick off and destroy the caterpillars. Sometimes they are hard to spot on your plants, since they are the same color as the plant. Mist your tomato plant in the morning and watch for shaking leaves - the hornworms move when wet.

Small caterpillars of all kinds can be controlled by applications of Bacillus thuringiensis (Bt) applied to the surfaces where the caterpillars feed. Bt is a microbial insecticide.

Another insecticide effective against small caterpillars is Spinosad, found in many ready-to-use commercial products for homeowners.

More information about control of tomato hornworms.

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