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Manduco, manducare, manducavi, manducatus, (Latin verb)
     to chew-devour-masticate-gnaw

That is exactly what this lovely caterpillar has done to our tomato plants for the past few weeks. The Manduca Sexta, commonly known as the Tobacco Hornworm, has gnawed, and chewed its way through our 40 foot greenhouse, destroying tomato plants, and damaging fruit at an alarming rate. At first glance, I thought our invader was a Tomato Hornworm (Manduca quinquemaculata), however, upon close inspection, and the with the help of an Entomology website, I discovered the correct identity. 

Tobacco Hornworm ~ Manduca Sexta

I first spotted the caterpillar the night before we were to leave on a 10 day trip. I let out a squeal when I first saw it. Its huge size, pointy red horn, and munching jaws, looked like something out of a horror movie. Our wwoofers would be tending to our farm, garden, and animals while we were away. As I walked through the greenhouse with Antony, pointing out the new seedlings in the cold frame that would need special attention, we spied a large caterpillar on one of the tomato plants. Then, we walked down the row of plants and found several more. Their light green color hides them well among the stems and leaves. Each one stretches three to four inches in length and are as big around as your thumb. The distinctive diagonal white markings, and red horn, distinguish the Tobacco Hornworm from the Tomato Hornworm. Antony picked up an empty plant pot and began picking them off of the plants. With a rather devilish grin on his face, he asked me if I thought the chickens would enjoy eating them, and he assured me that he would eradicate them by the time I had returned home. 

I had suspected that we had a problem, as I had seen droppings around the base of the plants. 

Droppings left by the Hornworm


Despite my efforts to find the caterpillars, they had remained hidden among the foliage until they were quite large. Now Antony and I searched each tomato plant, filling his pot with them. 

The Tobacco Hornworm represents the larval stage of the Sphinx or Hawk moth. These moths are quite large and often mistaken for hummingbirds. They lay in the soil all winter as brown pupae, and then emerge in the spring to mate. Their eggs, greenish-white in color, hatch within just a few days. 

The remains of a tomato plant attached by the hornworm.


The caterpillar begins gnawing its way to full size. Within four weeks time, the hornworm reaches adult size and heads back to the soil to pupate. 

Upon returning from our trip, Antony proudly said that the hornworms were taken care of. Each morning, he had gone out into the greenhouse, and searched among the foliage of the tomato plants. He would fill his little pot with caterpillars, and then head to the chickens in the field. He said that the hens got used to their daily treat of caterpillars and would gather around the fence
line when they saw him coming. 

This afternoon, I found another one, munching feverishly through a plant so I plucked it off and tossed it over the fence for the chickens. I think that once I put the greenhouse to bed, the hens will need to spend a few days inside the greenhouse, searching for any pupae beneath the soil in hopes that we do not have the return of the Tobacco Hornworm next summer.

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