Diary of an Average Gardener

Tomato Hornworm

– Posted in: Garden Tips and Info

Tomato Hornworms

very large tobacco hornworm

Very Large Tobacco Hornworm

 

One of a gardener’s worst nightmares is the tomato hornworm. It’s a huge caterpillar. When I say huge, I mean huge! They can reach 4 inches long by 1/2 inch in diameter; however, they can get bigger. Look at the size of this one.

 

 

They are green…like a leaf, so they are hard to see. So I didn’t notice a really large one until I noticed the top of my volunteer tomato had naked stems.   A single hornworm can devour a whole plant in a matter of a couple of days.  Don’t worry, they are harmless to humans. The horn on the tail is just to scare predators. This is not one of my pictures. I pulled it off the internet. I’m not going to hold one. I pluck or cut off the branch they are on and then stomp on them very hard.

 

tomato hornworm

Tobacco Hornworm found in my garden

 

I found the guy on the left this morning. Notice how he’s munched on the leaves. He was pretty small in comparison to the one above. I did take this picture. The head of the hornworm is on the right. The horn is on it’s tail. In this case, it is red. A red horn indicates that it is actually a tobacco hornworm, but they like tomatoes and peppers too. The picture below is a tomato hornworm. If the horn is black, then it is a tomato hornworm. Note the black horn on the tail. Someone at the University of Georgia took this picture.

tomato hornworm

Actual Tomato Hornworm

 

 

 

 

 

wasp_hornworm

Larvae Covered Hornworm

 

A natural predator of the hornworm is wasp larvae. In the picture to the right, those white, rice looking nodules on the hornworm’s back are wasps in the larva stage. The larvae will feed on the worm and eventually kill it. However, be aware that the worm could eat your plant before death happens,  The advice I found was to remove the stem with the worm place it in a jar with holes in the lid (like you did with lightening bugs) and let the wasp lavae continue to devour the worm. Be sure when the wasps begin to fly around, let them go. They will go lay more eggs, which will help you control the hornworm, as well as, pollinate your tomatoes.

 

Life Cycle of the Tomato Hornworm

The hornworm (which is really a caterpillar) starts as an egg laid by its adult form on the bottom of your tomato leaves. It takes 4 to 5 days for it to mature into the pupa or caterpillar stage. This is the stage that will eat the foliage off your tomato plants. The caterpillar stage can last a few weeks. I love to see the birds hanging around my garden…they will eat those hornworms. If the caterpillar is allowed to mature into its final stage of life…the hummingbird moth, you will probably get a second round of hornworms, so beware. However, late in the season, the pupa may drop off plants and bury into the ground and stay there until next summer. The adult moth does have benefits. They pollinate, eat other bugs, but I am not going to let the caterpillar stage ruin my garden. Sorry!