Between April and November, you might notice spike-tailed green worms (Figure 1) feasting on your tomato plants’ leaves and fruit. These voracious creatures ravaging your garden are caterpillars called tobacco or tomato hornworms. The caterpillars are the larval stage of Sphingidae adults—a family of stout-bodied and narrow-winged moths (Figure 2).
Figure 1. A tobacco hornworm, Manduca sexta, hanging from the stem of a tomato plant. Photograph by Lyle Buss, University of Florida.
Figure 2. The tomato hornworm moth, Manduca sexta. Photograph by James Castner.
The hornworm caterpillar in your garden might seem to appear out of nowhere, but it manages to camouflage itself very well while still small. The hornworm causes the most damage before going into the pupal stage, and it is probably then that you became aware of its presence.
Similar to the tomato hornworm is the tobacco hornworm. As its name implies, the tomato hornworm frequents tomato plants, and also feeds on tobacco. Likewise, the tobacco hornworm can be found on tomato plants as well as tobacco. Both species of caterpillar have been found on eggplant, pepper, and potato, though their occurrence on these plants is rare. The tobacco hornworm also develops into a Sphingid moth, but with slight variations in appearance throughout the life stages. In the juvenile stage, the tomato hornworm caterpillar and the tobacco hornworm caterpillar have different colored horns, black and red, respectively. The most distinct characteristic that differentiates the adult moths is a pair of yellow-orange spots that run vertically down the body. The tomato hornworm moth typically has five pairs of spots, while the tobacco hornworm moth usually displays six.
To learn more about these hornworms and how to control them, click here.
For more BugWeek information and activities, visit the website.
This guest post co-authored by Shari Linn, a member of the UF/IFAS Gillett-Kaufman Lab.