The tomato hornworm (Manduca quinquemaculata) is a caterpillar that infests plants of the Solanaceae family. Tomato hornworms can cause substantial damage to plants as they devour the leaves of this plant they have infested. The larva emerge from the ground during the summertime, and 2 tomato hornworms can defoliate an entire plant. Hornworm larva normally measure 3 to 3 1/2 inches in length and have bright green bodies with eight ‘v’-shaped marks on each side and also a identifiable ‘horn’ on their last body segment.
Hornworm Hosts
Tomato hornworm larva only infest plants from the Solanaceae — or even nightshade — family. The primary hosts for tomato hornworm are tomato and tobacco plants. In some cases tomato hornworm can also infest other garden plants, like pepper, eggplant or potato. This pest can also be located on horsenettle (Solanum carolinense) and numerous weeds at the nightshade family. In its adult moth stage, the tomato hornworm feeds on nectar from flowers.
Hornworm Biology
In their adult stage, tomato hornworms are known as the five-spotted hawkmoth. This big grey moth has a wingspan of 4 1/2 to 5 inches long. The five-spotted hawkmoth gets active at dusk and sets its eggs through the nighttime on the underside of host plants. Hornworm moths lay spherical eggs less than one-tenth of the inch in diameter using a light green color that turns white before hatching. The larva hatches from the flames approximately four days after they are laid and starts feeding on its host plant for about three weeks before burrowing into the ground where it spends the winter as a pupae.
Pest Control
Tomato hornworms are big caterpillars that are frequently difficult to spot. In most cases each host plant just supports a couple of hornworms that you can remove by hand. Hornworms have numerous natural enemies including parasitic wasps and flies. Tomato hornworms from the soil are located in the first few inches of the ground and can easily be destroyed by tilling. If your lawn is infested with tomato hornworms, meticulously tilling your lawn in the autumn can significantly reduce the amount of hornworms that return the next year.
Considerations
The massive quantity of the tomato hornworm allows it to inflict considerable damage on the plants that it infests. Most damage from the hornworm occurs during the middle and end of this summer season. If you discover hornworms in your garden, then check your plants and remove any tomato hornworms that you find weekly to prevent big, damaging populations in your lawn.