Tobacco Hornworm (Manduca Sexta)

A bain of tomato growers, tobacco hornworms can defolate young tomato plants with alarming speed. They can grow to over three-inches long and feed primarily on tomato or tobacco plants. If a hornworm is lucky enough to survive pupatation, its adult form is a large moth with yellow-orange spots on its abdomen and a four-inch wing span.

These impressively large and fleshy caterpillars are very similar to tomato hornworms. The color of the “horn” on their tail is perhaps the easiest way to tell the difference. A tomato hornworm will have a blue horn while the tobacco hornworm’s tail is red. Another easily identifiable difference are the extra black edges lining the stripes found on a tobacco hornworm’s back.

These worms must have been endemic when tobacco ruled the Piedmont’s agricultural landscape in the 18th and early-19th centuries. However, today they are not a major nuisance to the farm’s very limited number of tomato plants. Tilling in the spring usually breaks up their pupae and, if that doesn’t work, they can be easily plucked. More interesting are the parasitic wasps that use hornworms to complete their lifecycle. Unlike some parasitic wasps who paralyze their victims before dragging them back to an underground burrow, wasps who host on hornworms lay their eggs directly on their prey. After the eggs hatch the wasp larvae feed relentlessly on the slowly dying caterpillar until they are ready to take their adult form. Brutal but effective.

 

 

 

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