Indications Caterpillars are Present

• Examine plants for eaten foliage sections and bored holes in the tomato fruit. Look on the ground and nearby for caterpillar feces droppings. Lift tomato plant leaves and look for small, tiny white eggs or red and black eggs on the under-leaf plant surfaces. Eggs are typically laid in single rows near the tomato plant stems.
  
  

Hornworm Indentification

• One commonly found caterpillar on tomatoes is the tomato hornworm (Manduca quinquemaculata Haworth), advises the University of Florida IFAS Extension. The caterpillars are excellent at camouflage on tomato plants. The distinguishing feature is the small hook or horn found at the end of the body.
  
  Hornworms are light green. They range in size from 1/2 inch to several inches, advises the University of Florida IFAS Extension. It is not uncommon to entirely miss the presence of hornworms until they've consumed mass quantities of foliage.
  
  

Tomato Fruit Worm

• Another caterpillar frequently found on tomatoes is the tomato fruit worm (Helicoverpa zea), according to the University of Clemson Cooperative Extension. Like the hornworm, these tomato pests often are not noticed until extensive damage is done to tomato crops.
  
  The tomato fruit worm is most prevalent in South Carolina. Gardeners should note that the tomato fruit worm is a cannibal. It not only enjoys tomatoes, it will eat other caterpillars on the same branch or plant. Unlike the hornworm, the tomato fruit worm is most often found inside tomato fruit, causing extensive fruit rotting.
  
  

Controlling Tomato Caterpillars

• A common practice is to remove them by hand. However, with their excellent camouflage abilities, many can be missed. Use hand removal with other techniques for the best control.
  
  Both types of caterpillars winter in the top 2 inches of the soil. The University of Florida IFAS Extension and the Clemson University Extension recommend heavy tilling of garden soil prior to tomato planting to kill winter larvae.
  
  Companion plants such as borage attract wasps and other natural predators, which will readily consume caterpillars in tomato gardens.