Black Worms On Tomato Plants (4 Ways to Get Rid of Them)

Tomato plants are a favorite food source for many common garden pests. If you’ve noticed black worms on tomato plants in your house or garden, you need to know what they are and what you should be doing about it!

Growing your own tomatoes at home is one of the most satisfying and enjoyable gardening projects you can get into, but this is one of many pitfalls and perils to watch out for. 

Read on to discover everything you need to know about who these disruptive little creepy crawlies might be, and how to deal with black worms on tomato plants to save your crops from the attack!

What Are The Black Worms On Tomato Plants?

The first thing you will want to do is identify what the black worms on your tomato plants actually are.

The term “black worm” that is generally attributed to the wriggly pests that invade a tomato plant is a bit of a misnomer. They are almost always caterpillars, rather than worms, and they are rarely completely black.

They do, however, often have dark coloring and they move and behave a lot like worms, which is why they are generally given this name. Many of the caterpillar species that you might be dealing with have “worm” in their common name as well, like the “armyworm”, the “pinworm”, or the “cutworm”.

So, what sort of species are you likely to be dealing with and how can you get rid of them?

1. Black Cutworms (Agrotis ipsilon):

These particular “worms” are moth larvae and they get their name from the way that they cut through leaves and stems. They are a destructive pest that is about 1-2 inches long. Cutworms come in a variety of patterns and colors, although they are mainly brown, green, or grey and often have stripes running down their backs.

2. Tomato Fruitworms (Helicoverpa zea):

The larvae of another moth, tomato fruitworms are more commonly known as corn earworms and they are a major problem in agricultural production across the United States. They usually have orange heads, black thorax plates, and a primarily black body.

3. Tomato Pinworms (Keiferia lycopersicella):

Tomato pinworms are a particularly dark grey color and they perhaps look the most like a small black worm. You might spot strange patterns on your leaves if you are dealing with these particular pests as they tunnel into the leaves and make blotch mines.

If you want to learn more about leaf mining, you can read all about it in this article from the University of Wisconsin Milwaukee. 

4. Tomato Armyworms

There are actually quite a number of different species that are referred to as “armyworms” which you might be dealing with. In the 2020 edition of his book Handbook of Vegetable Pests, John L. Capinera describes the fall armyworm and yellowstriped armyworm as being two of the most problematic.

The yellowstriped armyworm in particular has quite a dark color compared to most of the other armyworm species, being almost black with thin yellow stripes on their sides.

Tomato hornworms are also a major pest that can cause havoc with your tomatoes, but these are green in color and quite bright. Hornworms can be very hard to spot because they are well camouflaged amongst the leaves and stems, but they do stand out under a blacklight. 

How To Remove Black Worms From Tomato Plants

Whether you are able to successfully identify the exact species of black worm that you are facing or not, the methods for removing them and preventing them from returning are often pretty similar.

1. Remove The Caterpillars And Eggs By Hand

The first thing that you can try is to simply remove the offending creatures by hand, but this can be a little tricky. You will need to get rid of every single worm if you don’t want them to keep popping back up again, and you will need to find and remove their eggs as well.

2. Use A Pesticide

Pesticide is often the most effective option, although many gardeners do try to avoid using overly strong chemicals. Bacillus Thuringiensis (BT) is a very common biological insecticide that you can add to the soil – as is Spinosad – or you can try Neem Oil as an organic alternative.

Homemade spray remedies can also be very effective. A mixture of one part liquid dish soap to ten parts water sprayed or wiped evenly over the entirety of the plant will kill off most worms. You can also create a repellent by placing a small amount of cayenne pepper or vinegar in water.

3. Introduce or Encourage Natural Predators

There are many natural predators that will keep black worms off your tomatoes, but they can be difficult to manage. Birds are often very good at hunting these pests, as are some other insects like lacewings, ladybugs, and soldier beetles.

4. Manage Your Soil

Many black worms will hide in the soil, particularly over colder months of the year, so tilling it and removing debris can clear them out. Keeping the soil as clean as possible is also one of the best ways to stop caterpillars from returning.

Also read: How To Keep Rabbits Out of Your Garden With Ivory Soap

Summary

So, what are the black worms on tomato plants and what should you do about it?

Most of the black worms that you find on tomato plants are caterpillars – usually either cutworms, pinworms, fruitworms, or armyworms.

To get rid of them, you can either remove them by hand, spray the plants with a pesticide/repellent, or encourage natural predators. Keeping your soil clear can also help, and it will reduce the likelihood that they will come back again next year.

Frequently Asked Questions