Tips for Finding and Eradicating Tomato Hornworms in Your Garden

Did you wake up one day to find the top portion of your tomato plant defoliated? Does it look like someone stripped the leaves off of your plant? Before you decide who to blame, and what steps to take to deal with the pest, look closer. Tomato hornworms are caterpillars of the five-spotted hawk moth. What starts off as a cute little caterpillar soon transforms into a large, ravenous beast that can take out an entire plant within a couple of days.

How to Spot Tomato Hornworms

In my 15+ years as a gardener I’ve only found tomato hornworms on my plants twice. The first time I discovered them was because I spotted the caterpillar’s poop on the leaves of my tomato while taking pictures for my garden blog.

I knew the clusters of tan-colored poop--that darkens to a charcoal-like appearance--weren’t normal, so I set about finding the source. Right above the clumps of poop was the resting hornworm. Look along the stems and on the underside of the leaves. Look closely because they’re masters of disguise and when you see them you’ll wonder how you missed something thicker than a hotdog crawling along your plant right in front of your face.

How to Kill Tomato Hornworms

The easiest way to kill a tomato hornworm is to cut it in half with a pair of scissors or pruning shears. If you are the squeamish kind, bring a pail of soapy water into the garden that you can drown them in. If you are a backyard chicken keeper, pluck them off and feed them to your hens.

Why You Should Not Kill Tomato Hornworms

If you are a fan of the moth that the hornworms transform into, let them be. Another reason that may call for a tomato hornworm stay of execution is when you encounter signs of parasitism. The tiny white cocoons are pupating braconid wasps. The braconid wasp is a natural predator of the tomato hornworm. As the tiny wasp undergoes metamorphosis it eats the insides of the hornworm until it dies. These wasps are beneficial insects in the garden and should be encouraged if you have a tomato hornworm problem.

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