Pest Wars, Part 2 - Tomato Hornworms

By Orion Darkwood

Tomato Hornworms

People ask me about pests and which ones I think are the worst. In a series of articles, I am listing my top 3. (See the first installment, here.) Number 2 is the lavra form of the five-spotted hawkmoth and closely related to the Tobacco Hornworm.

The larvae of this species can be distinguished by their lateral markings: tomato hornworms have eight V-shaped markings and a red horn while tobacco hornworms have seven diagonal lines and a black horn. Both feed on tomato plants. Just the mention of their name is enough to send shudders down many a gardener's spine.

In large numbers, the sound of them eating is very audible. Add to the fact that they blend in with the plant making detection of the actual worm hard. They can be quite sizeable as far as garden pests with some reaching 5 inches long. Lastly, they bite if provoked and excrete a green sticky goo that doesn't help.

Start looking the plants over in late spring for eggs and the adult form of the worm. Their eggs hatch in a week. The larva will feed for 4-6 weeks before creating a cocoon which it will emerge as a moth the following spring.

Luckily the damage these pests cause is obvious as stalks will be eaten bare - in fact smaller stalks could be completely eaten as well. The best way to find them is early morning or just after a rain when they will stand out more. Start at the top of the plant and work your way down checking under leaves and stalks. If you don't want to pull their heads off or smash them underfoot, drowning them in soapy water is a surefire method of killing them.

Other ways to control or combat them is a small braconid wasp. These wasps lay eggs on the hornworms. If one has little white eggs that look like grains of rice let the hornworm be. It will soon be paralyzed and will shortly become food. Common wasps also prey on the hornworm.

Also making sure the ground is well tilled before planting is a good way to destroy the cocoons that are in the ground. Lastly, people have reported success with companion planting of dill and marigolds around the tomato plants.

Orion Darkwood is an avid gardener, self reliance instructor, writer, poet and small business owner. To learn more about Orion and his comapny cgo to