There is nothing more frustrating than seeing worms on your tomato plants after careful cultivation of your garden. Unfortunately, there are many different types of worms that feed on tomato plants.
So, what kind of worms eat tomato plants? Tomato hornworms, armyworms, cutworms, and loopers are all different types of worms that eat tomato plants. They may feed on the leaves, stems, flowers, and fruit of the tomato plant.
Of course, you can tell the difference between these types of worms by their appearance and behavior.
In this article, we’ll take a closer look at the different types of worms that eat tomato plants and the life cycle of these worms. This will give us some hints on how to prevent or get rid of them in the future.
Let’s get started.
Hey – you can get our weekly gardening newsletter here!
Join 1000+ gardeners to get access to news, tips, and information.
Delivered right to your inbox – once per week.
What Kind of Worms Eat Tomato Plants?
The “worms” on your tomato plants are actually caterpillars, or the larval stage of moths. These larvae are often brown or green, and will feed on the leaves and other parts of your tomato plants.
The green worms can blend in easily with the leaves on your tomato plants, which give them excellent camouflage. In extreme cases, you may lose all of the leaves on a plant in one night if there are enough worms feeding on it!
The appearance and behavior of worms will help you to tell them apart, so let’s review them one at a time.
Types Of Worms That Eat Tomato Plants
Here are a few of the types of worms that eat tomato plants, along with a description of their appearance and activities.
Hornworm (Tomato Hornworm or Tobacco Hornworm)
There are two distinct varieties of tomato hornworms:
- tomato hornworms
- tobacco hornworms
Both of these types are bright green worms with long horns coming out of the back side. Both of them can feed on tomatoes, tobacco, and other nightshade plants such as peppers, eggplants, and potatoes.
Tomato hornworms have chevron stripes and a black horn on the back of the body. They are the larvae of the five-spotted hawkmoth.
For more information, check out this article on the five-spotted hawkmoth on Wikipedia.
You can also learn more in this article on tomato hornworms from the University of Minnesota Extension.
On the other hand, tobacco hornworms have diagonal stripes and a red horn on the back of the body. They are the larvae of the Carolina sphinx moth (also called the tobacco hawk moth).
For more information, check out this article on the Carolina sphinx moth on Wikipedia.
What Do Hornworms Eat?
In the spring, the moths of both hornworm species lay eggs on the bottom side of leaves, such as those on tomato plants. Later in the spring, the eggs hatch and larvae emerge.
The larvae then feed on leaves, eating the flesh and leaving the veins behind. If they survive the growing season, they spend the winter in the soil in cocoons.
Finally, moths emerge from the cocoons to lay eggs on the leaves of new plants, thus repeating the cycle.
Braconid wasps will often parasitize hornworms by laying eggs on their backs. When the wasp eggs hatch, they eat the hornworm from the inside out, and grow into mature wasps.
Armyworm
There are many types of armyworms, which are the larval stage of armyworm moths. Armyworms cause destruction to a variety of crops, including tomatoes.
Sometimes, armyworm larvae will practice cannibalism, eating other worms of the same species.
Usually, armyworm outbreaks occur in early summer, with most damage done in late summer.
Fall armyworms are brown or gray, and males have a white spot on each wing. Females lay eggs on the undersides of leaves, much like hornworms.
Armyworms exist in North America and South America, and the species recently invaded Africa.
For more information, check out this article from Wikipedia on armyworms.
You can also learn more in this article on armyworms from the University of Illinois Extension.
Cutworm
Cutworms are the larvae of moths such as the turnip moth or large yellow underwing. They can be green, brown, gray, or yellow.
A cutworm will crawl along in your garden until it finds a plant to attack. They will chew on leaves, buds, and stems.
The most damaging attack is at the stem of the plant. The cutworm will chew around the stem and eventually cut down the plant, causing it to fall over.
Fallen plants, severed at the stem near the soil line, is a telltale sign of cutworm damage. Some cutworms feed on a plant once they have cut it down, but others move on to attack additional plants.
If you are unlucky, a single cutworm will move along an entire row of tomatoes, cutting down multiple plants in one day.
Cutworm moths will lay their eggs in organic material in soil, such as compost or mulch. For more information, check out this article on cutworms from Wikipedia.
You can also read this article on cutworms from the University of Minnesota Extension.
If you want to find ways to deal with the problem of cutworms, check out my article on how to get rid of cutworms.
Looper
The cabbage looper is a green caterpillar of the owlet moth. It eats cruciferous vegetables such as broccoli and cabbage, but it can also affect beans, celery, lettuce, spinach, and tomatoes.
The larva arches its back into a loop as it crawls, giving it the name of looper.
The moths usually lay their eggs on the underside of leaves, often on higher and larger leaves on the plant. A single moth can lay one thousand or more eggs in a day.
For more information, check out this article on the cabbage looper from Wikipedia.
You can also read this article on the cabbage looper from the University of Massachusetts at Amherst.
Hey – you can get our weekly gardening newsletter here!
Join 1000+ gardeners to get access to news, tips, and information.
Delivered right to your inbox – once per week.
What Part Of The Tomato Plant Do Worms Eat?
As mentioned above, some worms will eat all parts of a tomato plant, including leaves, stems, flowers, and fruit. A severe infestation of worms on a tomato plant can lead to defoliation (loss of most or all leaves) in a single night!
Cutworms can destroy an entire plant, or multiple plants, without eating much of anything. Some of them will chew around the stem at the base of a plant and continue on to another plant after knocking one down.
Some worms also attack other plants in the nightshade family, such as:
- peppers
- eggplants
- potatoes
For this reason, it is a good idea to plant your tomatoes, peppers, eggplants, and potatoes in different parts of the garden.
This may not stop worms from moving around the garden. However, it will at least make things a little more difficult for them.
The more time they have to spend out in the open crawling between plants, the more time birds and other predators have to pick them off!
How To Get Rid Of Tomato Worms
Luckily, there are lots of ways to get rid of tomato worms. Some involve a little more work than others, and some involve welcoming guests to your garden to help you with the problem.
Sprinkle Your Plants With Diatomaceous Earth
Diatomaceous earth is a white powder that is often sold at garden centers. It is harmless for humans to handle, but if you looked at it under a microscope, it would look “sharp”, and indeed it is.
When insects crawl over diatomaceous earth or come into contact with it, the sharp pieces cut holes in their bodies. Eventually, they die of their injuries or due to dehydration.
Just remember that diatomaceous earth does not discriminate. Unfortunately, it will also kill good insects that you might want in your garden, such as ladybugs and bees.
If you decide to use diatomaceous earth on your plants, you may end up hurting pollinators. However, if you already hand pollinate due to a lack of bees, you may not mind using it.
When using diatomaceous earth, wear a mask to avoid breathing it in. The powder can irritate your lungs just like any other fine powder.
Spray Your Plants With Neem Oil
Neem oil has a harsh odor. It is used to kills or repel common garden pests, such as:
- aphids
- snails
- flies
- worms
The idea is to either kill the worms or to make the taste of the plant so unappealing that they will leave in search of greener pastures and tastier food.
As with diatomaceous earth, be sure to wear a mask when you use neem oil to avoid breathing it in. Also, wash it off if you get it on your hands, and avoid spraying plants that are already fruiting.
Order Some Ladybugs
Ladybugs are a beneficial insect in your garden. In addition to eating pests like aphids, ladybugs will also eat the eggs or young larva (worms) of moths.
You can order ladybugs online, such as these ones from Planet Natural, and release them into your garden. Another option is to try to attract them to your garden and let them do their thing once they show up.
Let The Wasps Be
If you have wasps in your yard or around your house, you might want to think twice before spraying them or calling pest control. Wasps will often parasitize worms with their eggs, laying dozens on a single moth larva.
When the eggs hatch, they will eat the worm from the inside out. The newly hatched wasps will then produce more larvae to help take care of other worms.
Make Birds Feel Welcome In Your Yard
Some birds love to eat worms. To combat worms, do your best to create a hospitable environment for birds in your yard.
Put some water in a birdbath – you can turn it into a water feature with a solar powered water pump. You can also set out some bird seed and hang up a few birdhouses to make birds feel welcome.
Hopefully, you will soon get some new residents that will help take care of insect pests.
Some birds may also eat from your plants, especially berries. However, the tradeoff may be worthwhile if you have a severe worm infestation on your hands.
Till The Soil Before Planting
Many species of moths spend the winter in the soil, in a compost pile, or in mulch. If you till your soil or stir up your compost pile, you are likely to disturb the life cycle of the moths by damaging them in their winter hibernation state.
Just be careful about tilling the soil if you have lots of earthworms, since this will disturb them. Earthworms improve the soil structure and break down organic matter into a form that plants can use.
For more information, check out my article on the cost of rototilling.
Practice Crop Rotation
Using crop rotation is one way to prevent infestations of worms in your garden. Rotate your crops in alternating 2, 3, or 4 year patterns.
Many worms often attack members of the nightshade family. For this reason, it helps to avoid planting nightshade plants in the same place year after year.
You can learn more about good crops to rotate with tomatoes in my article here.
Pick Worms Off Of Your Tomato Plants By Hand
As a last resort, you can go out and pick worms off of your tomato plants by hand to stop them from feeding. You may have to do this at night, since some worms, such as the cutworm, feed nocturnally.
You can put the worms in soapy water or crush them to kill them.
Conclusion
The following table summarizes the 4 types of worms we discussed in this article, along with what they look like.
| Worm Type | Appearance |
|---|---|
| Tomato hornworm | green with chevron stripes & black horn on back |
| Tobacco hornworm | green with diagonal stripes & red horn on back |
| Armyworm | green, brown or gray with stripes & an inverted Y on head |
| Cutworm | green, brown, gray, or yellow, they often curl into a C shape |
| Looper | green, often with a white stripe on each side |
eat tomato plants and their appearance.
Now you know about some of the more common worms that may be attacking your tomato plants and how to identify them. You also have an idea of how to fight or prevent them in the future.
You can learn more about biological pest control in this article.
You might also be interested in my article on organic pest control and my article on plant collars.
If your tomato plant has black on the stems or leaves, check out this article to learn more about why it might be happening.
I hope you found this article helpful – if so, please share it with someone who can use the information.
To find books, courses, seeds, gardening supplies, and more, check out The Shop at Greenupside!
Hey – you can get our weekly gardening newsletter here!
Join 1000+ gardeners to get access to news, tips, and information.
Delivered right to your inbox – once per week.
If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here. Enjoy!
~Jonathon