Tomato-Eating Black Moths

Life Cycle

• Sphinx or hummingbird moths spend the winter months in a cocoon. When spring arrives, the moths emerge and mate. The female lays eggs on low-lying plants and leaves and, within three to four weeks, the eggs hatch and the tomato horn worm emerges. The caterpillar will feed on nearby leaves and plants until they are fully grown and can spin a cocoon. In the cocoon, the caterpillar is now a pupae and will stay in this stage through the winter, emerging again in the spring as a full-grown moth.

Identification

• The tomato horn worm is one of the largest caterpillars, according to the University of Minnesota. The caterpillars can grow up to 4 inches long and the coloring will change as the insect matures. Young tomato horn worms are white or yellow, but as the animal gets older, it will become more green and develop eight V-shaped marks on each side. The sphinx or hawk moth are large insects with smaller front wings. The moths are black or brown with yellow markings on the side. The body of the moth ranges from 4 to 6 inches.

Damage

• Tomato horn worms cause the most damage to tomato plants, eating both the leaves and the actual tomatoes. The sphinx or hummingbird moths do not actually eat the tomatoes themselves, but the insects will eat small amounts of the tomato plants. In addition, when the moths lay eggs on the tomato plants, the actual process of attaching the eggs to the leaves can cause additional damage to the plant. If your tomato plants have sphinx or hummingbird moths near them, you are most likely going to find tomato horn worms in your garden as well.

Proper Care

• Preventing the moths and caterpillars from taking up residence in your garden is the easiest way to keep your tomato plants safe. The University of Minnesota suggests keeping your garden as weed-free as possible to remove additional food and egg-laying locations. In addition, till your soil in the fall after harvesting your garden to kill any pupae that are buried in the soil and will hatch in the spring. If you have tomato horn worms on your plants, the best way to remove them is by hand. Throw the worms in soapy water to kill them. You can also use caterpillar pesticide sprays, which are available at home and garden stores. Just be sure to buy one that is safe for use on vegetable and fruit plants.