Tomato Hornworms: 4 Tomato Hornworm Control Methods

A tomato hornworm (Manduca quinquemaculata), also known as a tomato worm, is a caterpillar that feeds on tomato leaves and other plants in the Solanaceae family, including eggplants, peppers, and potatoes. These garden pests are common in Australia and North America, particularly in the northern United States. Tomato hornworms pupate underground and emerge as five-spotted, black-and-grey moths known as hawk moths or sphinx moths.

In late spring, females lay eggs on host plants in vegetable gardens. Eggs hatch in a week and grow to be green caterpillars almost four inches in length. The caterpillars become pupae in the early fall. The pupae overwinter in their cocoons in the soil near host plants and emerge as adults—with a wingspan of five inches—the following summer before mating and restarting the life cycle.

Tomato hornworms are sometimes confused with tobacco hornworms (Manduca sexta), which also live in North America but are more frequently found in the South. There are key ways to identify the tomato hornworm at each stage of its life cycle:

• Eggs: Females lay eggs one by one on the surface of host plants. The eggs can be anywhere from a creamy white to a lighter green.
• Larvae: During the larva phase during which they feed on tomato plants, tomato hornworms can be a couple of inches long and have a short, black posterior horn that juts out and curves slightly downward. In contrast, M. Sexta caterpillars feature white stripes and a red horn.
• Adult moths: After they pupate, adult moths have brown-and-gray wings, two antennae, and five rows of yellow spots on their bodies (whereas the M. sexta have six). Larger tomato hornworm moths’ wingspans can surpass five inches.

Hornworm caterpillar infestations are common in North American home gardens in early spring. Missing leaves or holes can indicate a tomato hornworm’s presence. You might also notice dark, black droppings on your vegetable garden leaves or white cocoons near Solanaceae host plants. Tomato hornworms can devastate a garden by chewing through leaves.

If you suspect your garden has a tomato hornworm infestation, the good news is you don’t have to call pest control to protect your tomato crop. There are several DIY ways to prevent and oust these garden pests:

1. 1. Keep your garden free of Solanaceae weeds. Tomato hornworms can feed off any type of Solanaceae plant. Keep your garden free of nightshades such as horsenettle and jimsonweed, and be sure to clear your garden of any plant litter after the growing season to prevent tomato hornworms.
2. 2. Employ natural enemies. When it comes to ridding your garden of hornworms, wasps are beneficial insects. The wasp is a tomato worm’s natural enemy, so keeping these insects around can act as a natural biological control. Green lacewings and ladybugs eat hornworm eggs.
3. 3. Handpick tomato hornworms. Don’t worry—tomato hornworm caterpillars don’t bite or sting, so they are easy to pick up and remove from your garden, especially if you wear gloves. Drop the pests in soapy water, add them to a bird feeder, or feed them to chickens if you own a coop.
4. 4. Use dish soap to deter the worms. Fill a spray bottle with tap water and add a few drops of dish soap. Mix it and gently spray your tomato leaves with the mixture. This method will deter the worms from feeding on your plants; add cayenne pepper to the mix to further repel hornworms.

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