TOBACCO AND TOMATO HORNWORM

This page is for boys... specifically ones who like bugs and guts and things that crawl and squish. That's what you may be in for when you (unavoidably) face down this big, juicy beast.

The tobacco hornworm (Manduca sexta) and tomato hornworm (Manduca quinquemaculata) are the bright green larva of the tobacco hawk moth and five-spotted hawkmoth, respecitvely. These two are often mistaken for one another, which is understandable, but each will make fast work of your tomatoes, peppers, eggplants and, well, tobacco, all members of the Solanaceae family.

To this caterpillar, who easily tops 3", all these plants mean lunch.

TOBACCO HORNWORM: STRIPES ARE STRAIGHT — TOBACCO HORNWORM: STRIPES ARE STRAIGHT

Unlike squash bugs and beetles, who carry out their work on predictable timetable, hornworms can devastate a plant in a matter of hours.

Their appetite for foliage is wonder-inducing, and when you multiply the damage a single hornworm can do by several of its litter-mates, your lack of vigilance can cost you half a season of effort overnight.

What do to? First, learn to spot their eggs, which are little green translucent ovals usually deposited on the underside of leaves. When you see them, be sure to squish them or scrape them off onto a surface where they will not survive.

Another telltale sign is their poop, which looks like little green berries (when fresh) no bigger than a small pea. If you see fresh droppings, just use gravity and common sense to locate and eliminate the "poopetrator."

Masters of Deception

Nature is persistent, and you must be too! Hornworms are famously deceptive and sport one of nature's best camouflage color schemes. You may spend 10 minutes or more hunting down a single caterpillar that is right in front of your face. Turn leaves over, stoop down, walk around... and repeat! And there's a good chance that if you've spotted one, there's another around, so keep after it and look for all the signs of the presence of these nasty pests.

How to kill? First, be aware that you can touch these guys, although they will rear up defensively and/or grab onto the plant stem with a tenacious grip, making it unexpectedly hard to just pluck them off the plant. Also, the "horn" is harmless—it is not a stinger.

But the fastest way to eradicate hornworms caught in flagrante delicioso is simply to cut them in half—very carefully, so as not to harm the plant stem. Use a pair of sharp garden shears and just "snip" their soft bodies right in two. No lies... it's pretty gross, but if you've tried to extricate one of these buggers by hand, you'll come to appreciate this technique. One way or another, if you don't get rid of these guys, you are guaranteed to end up with something like the damage shown below.

Where's mamma?

The reason you're not likely to stop the hornworm when it's just a twinkle in mamma's eyes: she's a lady of the night (being a moth and all). But if you are out late and do spot a tobacco hawk moth hanging around, swat her down!

Natural Control

The braconid wasp is a natural predator of the tobacco hornworm. The larvae of these wasps are parasitic to the hornworm, and their cocoons can be seen protruding from the backs of infested caterpillars. As with other natural controls, we will explore their proactive application.

But just know that—as always—the best defense is a good offense: Get out in the garden and check your plants frequently! Between beetles, bugs, and hornworms, your eyes and hands are the best defense!