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How To Stop Tomato Hornworms – Keeping Your Tomato Crop Safe!

Summer is here, and that means it is time to stop tomato hornworms before they damage and destroy your crop!

When it comes to destructive summer garden pests, tobacco and tomato hornworms might just top the list. The ugly green creatures can measure 4 to 5 inches long, and devour tomato and pepper plants overnight.

Hornworms are found in almost every corner of the United States and beyond. There are actually two types, and depending on where you live, you might have one or both attempting to ruin your garden. 

Tomato hornworms have a dark spike at the point of their back side, and 8 white stripes down their body. Tobacco hornworms, on the other hand, have a red spike with 7 white stripes.

stopping the tomato hornworm
Tomato hornworms can quickly munch their way through your crop. One thing is for sure, early detection is the key to success!

Tomato hornworms are more prevalent in the north, while tobacco hornworms are found in the south and Southwest. They both can quickly decimate the Nightshade family of plants, which include tomatoes, peppers, potatoes, and tobacco plants.

The Arrival Of Hornworms – How To Stop Tomato Hornworms

Hornworms emerge from the ground as pupa in late spring in the form of a large moth. These moths are dark brown and have the flight skills of a hummingbird.

They can hover over plants and be nearly impossible to catch due to their quick nature. The moths then lay small eggs on the undersides of plants, which then emerge as hornworm caterpillars. And the damage begins!

Spotting The Damage – How To Stop Tomato Hornworms

Hornworms come to life and start their foraging at the peak of summer. Their damage is easy to spot. The large green caterpillars usually start stripping off and devouring leaves and stems at or near the top of plants.

how to stop tomato hornworms
One of the most difficult aspects of controlling hornworms is actually finding them. Their outer skin is amazingly colored to blend in with tomato plants. With that said, there are a few simple hints that can make finding them a bit easier.

If you notice the tops of your plants missing large chunks of foliage, with only stubbed remnants left of the branches – you most likely have hornworms!

Once they have devoured the leaves and stems, they will find their way on to the ripening fruit. If left alone, tomato hornworms can ruin every tomato on a plant in just a few days. They are sloppy eaters, and will move from fruit to fruit quickly.

Although their damage might be easy to spot, the tobacco and tomato hornworms are not! Their translucent green bodies camouflage them perfectly against the leaves of garden plants. It’s almost like trying to play a game of “Where’s Waldo” trying to locate them on damaged plants. 

vegetable garden plant damage
The damage can be easy to spot, but the culprit can be hard to find. Once you see branches that are stunted. you know that hornworms have been working your plants.

How To Stop Tomato Hornworms

There are a few organic insecticides available, but they are not highly effective, and kill many beneficial insects too. As for standard insecticides, they have the same issue of killing beneficial insects. And to boot – who wants to be spraying insecticides on the tomatoes they will be eating?!

The single, most effective method to control hornworms is the old-fashioned art of daily patrol and hand picking. But they key to total control starts and ends with the word “daily.” 

In just a 2 day period, the caterpillars can go from 1/2″ long to 4″ from eating everything in sight. But the good news is that if you are diligent in your efforts, it really does work, and it will keep your crop safe!

Beyond looking for the tell-tale damage to foliage and stems at the top of the plants, be on the lookout for other earlier signs. Hornworms will leave small piles of droppings on the top side of leaves. (Check out the video below for how to search your plants!)

If it is bright green, it is fresh, and the hornworm is nearby. If it is darker or dry, it is a bit older and look lower or higher in the plant for the culprit. Once you have trained your eyes, it is amazing how quickly you can start to spot the damage and remove them.

The End Of The Line For Hornworms – How To Stop Tomato Hornworms

If you happen to have chickens, feed the worms to them, they love them! If not, chop them in half and dispose. But whatever you do, don’t relocate them – they will find their way back!

There is one time that it is better to remove the hornworms from your plants. If you spot a hornworm with small white protrusions on it’s back, leave it be.

parasitic wasps
If you see a hornworm with white spots, it is actually a good sign. The white spots are the eggs of a parasitic wasp that will kill the hornworm.

Those white spots are the eggs of parasitic and extremely beneficial wasps. If they are present, the hornworm is not a danger to your crops and will soon die. And by leaving it, those wasps can hatch and find their way to take out other hornworms.

Parasitic wasps and wasps in general are great for your tomato garden. In fact, they are one of the best pollinators of all for tomato plants! See : How Wasps Help Tomato Plants – And Your Vegetable Garden Too!

Long Term Control

One of the best natural controls against tobacco and tomato hornworms in the long-term is chickens. If you are fortunate to have a small flock, let them forage in the garden each fall after the crops have been pulled.

They can scratch and clear the pupa from the ground, eliminating most of the next years batch. In fact, it is amazing how effective they can be at eliminating next year’s problems!

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If you unearth any of the brown pupa while digging, destroy them as well. They are usually only a 1/4″ or less under the soil, and look like the hardened shell of a small caterpillar.

With a little diligence, you can keep hornworms at bay! For other summertime garden tips, check out our Garden Guide page on the blog.

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