Tomato Hornworms

Tomatoe Hornworms with Sensible Gardening

The first time I sighted a tomato hornworm (Manduca quinquemaculata) I could hardly believe my eyes.

Tomatoe Hornworms with Sensible Gardening

About to pick off a beautiful ripe tomato my fingers lightly brushed against this garden monster. I really thought I must have come across some rare mutant caterpillar, but upon a little investigation I realized this creature is all too common in the vegetable patch.

What are Tomato Hornworms?

Tomato Hornworms with Sensible Gardening

Tomato hornworms are related to the tobacco hornworm, apparently almost identical. Another reason not to smoke. The larvae grow to 4 inches and are colored a bright yellow green  with diagonal white stripes down the sides. Each stripe has a black dot punctuated by a false eye dot and their tail is black. The adults are huge grayish brown moths known as hawk or hummingbird moths.  Quite spectacular with wingspans of 5 inches covered with wavy lined patterns and orange spots. They winter in a hard pupal case slightly underground. Come spring the adult emerges and lays green yellow eggs on the underside of host leaves. The eggs hatch and the larvae grow to full size within a month.  These caterpillars turn into the moths and the hornworm life cycle repeats itself.

Tomato Hornworms with Sensible Gardening

Where will you find Hornworms?

Found throughout North America hornworms prefer open cultivated areas, just like your vegetable garden. They love tomatoes, potatoes, peppers, beets, eggplant and tobacco. Even with their large size they can be very hard to find even in broad daylight as they have excellent camouflage. Hornworms are capable of eating a very large amount of leaves and sometimes nibble on the fruit as well.

How to get rid of Hornworms?

Tomato Hornworms with Sensible Gardening

Probably the best way to rid your garden of these monster pests is to hand pick them. Easier said than done. Use gloves or your snips as tweezers to pluck them off the stems. I then usually place them in a container of water to perish, stomping underfoot is really not an option for this gardener. Luckily  hornworms are usually low in numbers.

If you till your garden in the fall you will destroy many of the underground pupae. Rotating crops and providing crop covers can also be helpful. There is also a certain type of wasp that lays cocoons on the hornworms body. This kills the hornworm and the hatching wasps parasitize the hornworm’s eggs.

If you have come across these hornworms in your garden you know all too well what I mean when I compare them to outer space garden pests.

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Tomatoe Hornworms with Sensible Gardening

(some photos are from pixabay)


5 thoughts on “Tomato Hornworms

  1. The adult form is quite amazing too – they are a shock if you see the caterpillars in the garden though – they’re huge

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