Natural History – The Tomato Hornworm
I have often described myself as “a curious naturalist,” (especially after I read “The Curious Naturalist” by Sy Montgomery). Perhaps, the garden helps feed my “curious naturalist” gene. For example, this morning while encouraging the tomato plants, I noticed some leaf damage on one plant. It did not take long to spot the culprit—a tomato hornworm.
The Tomato Hornworm
The first thing I did was carefully collect the critter and bring it to the house for a photo shoot. The caterpillar is a little more than two inches long with a body about the diameter of a round pencil. The hornworm can be a serious pest in gardens. An infestation of them can quickly defoliate tomato and even potato plants. The best way to control them is to carry a jar of soapy water to the garden and drop the caterpillars into the water. There are pesticides, but since the caterpillar is large, easy to spot, and easy to control, pesticides may be an unnecessary expense—and I prefer a non-pesticide approach.
Tomato hornworms feed almost exclusively on plants in the family Solanaceae, a large family of plants that includes 98 genera and 2,700 species. This family includes nightshade, potato, eggplant, tomato, and tobacco.
The “Horn” of the Tomato Hornworm. The small oval spots on its side are spiracles for gas exchange (breathing).
The tomato hornworm is one of the largest caterpillars ound in gardens. They get their name from the curved spike on the aft end of the abdomen. After hatching, the hornworm begins life as a small white caterpillar. As it grows, it gradually turns green, with a pattern of v-shaped marks along the side of its back. Its color closely matches that of tomato leaves and stems.
It takes about four weeks for the hornworm to grow to full size, after which, it drops to, and burrows into the ground where is enters the pupa stage. It will over-winter in the ground, and emerge as a hawkmoth in early summer.
The Tomato Hornworm’s color closely matches the color of tomato leaves and stems.
The tomato hornworm is the larva of the five-spotted hawkmoth, and, to me, hawkmoths are really cool. Also called the “sphinx” or “hummingbird” moth, they are large, thick-bodied moths that can be seen hovering, hummingbird-like, at the blossoms of solanaceous plants, especially evening nightshade. They are gray and brown, with spotted bodies and wings. Their wing span can be as much as five inches.
Photography and text Copyrighted: 2016 Jeff Richmond
Renaissance Musings 
That is a happy hornworm. We have found them in our garden covered with the evidence of wasp eggs. Regardless, hornworms are so good at camouflage I find them to be creepy. Great pictures!
I appreciate the comment. If they did not attack my tomatoes, I would like them because I think the hawkmoth is so cool–I have great memories of them on the farm when I was a boy.
Several years ago my daughter Kimberly found one of these on one of my container potted
tomato plants. She was convinced it would turn into a morarch butterfly. So we made him a cage and feed him greens daily. You have never seen such an eater. And as they say what goes in must come out. The excrement looked like the worm with ridges. Finally after about a week i googled the likes of him only to learn it was never going to be a monarch butterfly but was a common tomato hornworm.