Horn Worms Diet

Tomatoes

• Species called tomato hornworms feed primarily on relatives of the tomato plant, called solonaceous plants. They may also eat peppers, potatoes, eggplant, jimsonweed, nightshade and similar species. They eat mostly on the upper portions of the leaves, but as the caterpillar grows, they may consume entire leaves and stems. Some tomato hornworms also eat the fruit of the plant. According to the University of Minnesota, tomato hornworms in the last stage of growth can eat almost as much in this stage as they consumed during the entire rest of their development.
  
  

Tobacco

• The tobacco hornworm is the larva of the Carolina sphinx moth, and is one of the few insects capable of surviving the nicotine content of tobacco leaves. They can be recognized by the curved red horn on the rear of their bodies and the diagonal white lines down their sides. Despite the name, these creatures can eat other plants as well, and may be found on tomatoes and other garden plants.
  
  

Other Species

• While the tomato and tobacco hornworms can cause problems in gardens, there are many other species of hornworm which are not considered pests. According to the University of Colorado, there are more than 30 hornworm species in that state, most of which are not commonly seen and don't cause serious damage to wild or domestic plants. These species include the white-lined sphinx caterpillar, which feeds on primrose, wild grape and similar plants, and tree-dwelling hornworm species like the big poplar sphinx caterpillar.
  
  

Damage

• While hornworms are very obvious garden pests, they rarely do a lot of damage to big crops. According to the University of Minnesota, hornworm populations do not grow large enough to do economically significant damage to commercial farm crops. At home, however, these creatures may eat enough leaves from the plants in small gardens to disrupt the harvest. Removing hornworms from plants while they are still small and tilling the soil after harvest can help preserve plants and reduce the hornworm population.
  
  

Considerations

• Hornworms develop into attractive and useful moths, which pollinate a number of plant species. Unless these caterpillars are observed damaging garden plants, gardeners should leave them alone. Most hornworm species never reach populations capable of causing serious damage to wild plants, and they rarely damage any economically important vegetation.