Tomato worms are not something that you want to find in your garden, especially if you have a tomato plant!
As the name reveals, tomato hornworms are pests that feed on tomatoes and other plants in the nightshade family.
But where do tomato worms come from?
The answer isthe tomato hornworm is technically not a worm, but a caterpillar and is a larvae of the Sphinx moth.
KEY TAKEAWAYS
- These moths lay eggs in the late spring or early summer on tomato, eggplant, pepper, and potato plants.
- When the eggs hatch, the tomato hornworm caterpillar will eat until it matures (around 18-21 days)
- It then burrows into the soil to transition into the pupae stage.
- You have a few options for getting rid of tomato hornworms: Pick them off by hand if you only have a few infested plants, add beneficial insects and natural predators, or use organic pesticides or insecticides (as a last resort)
The tomato hornworm can also attack:
- Eggplant
- Peppers
- Potatoes
- Tomatillos
- Tobacco plants (that’s why you may hear them referred to as “tobacco hornworms”)
- And other vegetable plants!
If left unchecked, they will quickly destroy all of your plants and leave you with an infested garden full of rotting vegetation.
What Are Tomato Worms And Where Do They Come From?
Tomato worms are the larvae of a particular species of moth known scientifically as Helicoverpa zea.
These moths lay their eggs in late spring or early summer on tomato, eggplant, pepper, and potato plants.
When the eggs hatch, the larvae will feed on these plants for several weeks – around 18-21 days usually – until it reaches a length of around 3 to 4 inches (or 7-10 cm long).
Tomato hornworms will then enter the soil and pupate, ready to grow into Hummingbird moths (another common name for the Sphinx moth).
Can I Tell If I Have Tomato Worms By Looking At My Plants?
Tomato worms or caterpillars can be identified as large green worms with black stripes on their sides and yellow spots along their backs.
A fully grown tomato worm can be up to two inches long
They will also sometimes leave frass (droppings) hanging from your plant leaves.
This is a good indication that you may have a problem.
In severe infestations, this frass may even coat the entire trunk of your tomato plant.
Of course, if you notice your nightshade plants and their fruits and plant tissues being decimated, then you can make a pretty good guess that you have a tomato hornworm problem.
How Did I Get a Tomato Worm Plant Infestation?
The answer to the question of where do tomato worms come from is that they crawl into your garden and begin feasting on your crops at night.
This is why you don’t see any damage during the day.
They like to dine within the foliage and on fruit.
So you will need to inspect both areas of your tomato plant thoroughly.
If there’s one caterpillar present, there will likely be much more hiding in other places.
Symptoms Of Infestation With Tomato Worms
At night, these pests will eat holes through the leaves of all parts of your tomato plants.
These perforations won’t always be visible.
But they will cause your leaves to droop, and eventually, they’ll begin to wither, fall off completely, and die.
The real damage, however, takes place when tomato worms feed on fruit.
They love the taste of tomato flesh, so once they find their way onto a fruit-bearing plant, they typically crawl into it and make themselves at home.
They will feast until the entire thing has been hollowed out.
This process can take just a few days or longer, depending on the severity of the infestation.
If you’ve found your tomato plants are infested with worms, then it’s time to start worrying!
This is when things can get really serious and it’s time to find a treatment to get rid of tomato hornworms..
How to Get Rid of Tomato Hornworms: Treatment For Infested Tomatoes
It is best to act quickly before your plants are too damaged, or you will have to dig up all of the garden soil and get the infected plants out.
The tomato worms themselves aren’t difficult to treat.
Pick Them Off by Hand if You only Have a Few Infested Plants
This only works for a small hornworm population.
First, try to find tomato hornworms on your plants and pick them off.
Then add a layer of mulch around the base of your tomato plants so that larvae won’t be able to crawl up from the soil below.
You can then get rid of tomato hornworms you’ve found by dumping them in soapy water to kill them, or use them as fish bait if you’re an angler!
It’s important to be wary of other kinds of infestations too because these moths tend to lay their tomato hornworm eggs at the same time each year.
So, if one generation makes it through a summer, then it is likely that they will come back in greater numbers the next summer.
Add Beneficial Insects and Natural Predators
Adding beneficial insects is a good way to get rid of tomato hornworms. They have some natural predatory insects who wouldn’t mind taking a bite out of them for you like:
- Ladybugs (eat their eggs)
- Lacewings (eat their eggs)
- Wasps
- Trichogramma pretiosum (parasitic wasps that lay eggs on the tomato hornworm. The wasp larvae stops them from eating, and eventually kills them)
You can either buy them online or maybe try to lure them into your garden by providing shelter, water, some flowers and avoid using insecticide to control hornworms.
Which goes against the next solution which you should only use to prevent hornworms as a last resort..
Use Organic Pesticide/insecticide (last Resort)
As a very last resort, you may use organic pesticide, but this isn’t recommended as you may harm beneficial insects.
You have two options here:
- You can make your own at home by adding cayenne pepper to water in a spray bottle and spraying them over the tomato hornworm covered plant foliage.
The tomato hornworm and other pests will not eat any plants sprayed with this solution and it also won’t burn or cause damage to your green foliage.
Though if any of it lands away from the tomato leaves or your other nightshade plants and lands in the soil, you could cause damage to other beneficial insects or earthworms.
- You can use a commercial organic product – like Dipel dust, Sevin or BT (Bacillus thuringiensis).
These are beneficial nematodes, a type of barely visible worm-like creatures that get into pests and kill them.
They are a form of organic insecticides known for controlling caterpillars when they eat them.
They tend not to harm beneficial insects and only kill soil-dwelling pests (apart from earthworms, thankfully!) but this was recently challenged by a study in the PeerJ Journal of Life and Environment that saw them kill bees within 48 hours.
They may kill tomato hornworms naturally but if you have bees in your garden, stay away from this solution. Bees are highly beneficial insects.
How to Prevent Tomato Hornworms Infestation
If you garden organically, you can prevent tomato hornworms by trapping these caterpillars with yellow sticky traps before they lay their eggs in your tomato plants.
This is an effective measure prevent tomato worms and eventually eliminate hornworms from your yard by stopping them multiplying.
There are also other ways to avoid tomato hornworms naturally coming back again:
- Rotate crops as much as you can. Crop rotation means planting different plants in different parts of your garden or fields each year. This helps prevent hornworms
- Try to attract their predators (as mentioned above) into your garden as quickly as possible or order them online to easily control hornworms.
- Also, make sure to clean your garden well at the end of the summer (picking up any fruit that has fallen off and throwing it away properly) since this will help prevent future infestations.
- Use diatomaceous earth in advance which kills them as they crawl over them and accidentally consume the microscopically sharp particles.
- Keep an eye out for early signs of infestation so that it doesn’t spread too far into the rest of your garden.
- Use organic methods instead of chemical ones when possible.
Why Is It Important To Get Rid Of Tomato Worms?
Well, first off, these caterpillars can be harmful to humans since they have stinging hairs on their backs that can cause severe pain and discomfort.
The frass they leave behind is unattractive and makes the tomatoes look unappealing (not fit for sale), which is why farmers want them gone!
To Sum It Up
Whether you know it as the tomato hornworm, the tobacco hornworm or by their various moth names like hawk moths, sphinx moths, five spotted hawk moth etc you’ll know them as a very real pest that can wreak havoc on your tomato plants.
Now you know where tomato worms come from, how to identify hornworm damage and how to avoid them.
These pests feed on fruits and leaves, quickly killing the plant if left untreated.
Thankfully there are organic ways to fight back and get rid of tomato hornworms, like using yellow sticky traps or hand picking them off with gloves (wear rubber ones) and the ones we mentioned in this article.
Lastly, be sure to clean up fallen fruit at the end of summer so that next year this garden pest won’t come back with a vengeance.
You may also find worms in strawberries, but these aren’t tomato hornworms. In this case, you might also want to read our answer to the question, can worms eat strawberries?
REFERENCES:
A new threat to bees? Entomopathogenic nematodes used in biological pest control cause rapid mortality in Bombus terrestris – https://peerj.com/articles/1413/
