Last Updated on July 1, 2020 by Matt Gardener
Have you ever wondered how to get rid of tomato hornworms?
If that’s true, then you’re lucky! That is precisely what you’re going to learn today.
If you have been growing tomatoes in your garden for a while now, then the chances are good that you have encountered or will encounter these green pests, so brace up for the battle ahead.
These little monsters are highly invasive, and they do great work in blending just fine amongst other green plants.
They feed vigorously, causing extensive damage to leaves, plants, and fruits as a whole if not controlled quickly and early.
But don’t be troubled, here is how to identify and eliminate tomatoes hornworms in your garden.
Read Also: How to Protect Tomato Plants from Bugs
Table of Contents
Tomato Hornworm Life Cycle
Before you find out how to get rid of tomato hornworms, it is essential to learn where they come from and how they grow, so you know how they grow, what to look for and how to tackle them.
Now you are asking where do tomato worms come from?
These tomato hornworms are simply pests that undergo four stages during their life cycle before forming into what you call the tomato worm: Eggs, Larvae, Pupae, and Adult.
The tomato hornworm life cycle begins as the overwintering adults move out of the soil.
During the late season of spring, giant adult moths come out from within the soil and lay spherical eggs which are whitish to light green in color.
This reproduction usually occurs on the undersides of leaves belonging to their choice of plant-often plants in the Solanaceae (nightshade) family, which includes tomatoes and others.
Still, they are most active in tomato plants.
The laying of the egg stage is known as the first instar stage. The eggs hatch within a week or a minimum of five days of being laid, and a tiny green worm appears.
The next stage occurs in the next 18-21 days after hatching; during this stage, the small worm begins to shed layers of skin and multiplies.
- 1st Instar – (2-3 days); weight .03 grams; length about 1/4 inch
- 2nd Instar – (6-9 days); weight about 5 grams
- 3rd Instar – (10-12 days) weight and height will vary
- 4th Instar – (13-17 days) varies
- 5th Instar – (17-21 days) weight at least 10 grams; length 3-5 inches
After hatching, the larvae begin its life cycle above the ground. This lifecycle involves a multi-faceted series of actions that are completed within a month.
The adult moths are quickly noticed and are usually called hummingbird moth or sphinx.
At the end of the month, they burrow beneath the soil, and if the weather is favorable enough, larvae may only burrow for as little as 2–3 weeks.
At this stage, the tomato hookworm wears the form of a caterpillar (Manduca quinquemaculata).
This stage lasts for two-to-four weeks. At this point, it has overwintered beneath the soil in a big reddish-brown pupal state. This stage is known as the pupal stage.
In the late spring, the pupae will “drop” when it completes feeding and growing. It will hatch and burrow into the ground and pupate.
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Then a giant moth emerges known as the five spotted hawk moth or sphinx moth.
This stage is known as the Adult Stage of the tomato hornworm. The moth will keep feeding off the nectar of different flowers until full maturity.
At the end of the season, moths will overwinter in the soil and then lay eggs once again in late next spring.
This cycle usually completes twice annually-late spring and mid-summer; for this reason, more than one generation may be expected, especially in warmer climates.
Knowing the life cycle of tomato hornworms is as important as getting rid of them.
It is crucial to know that you are likely to expect 2 to 3 rounds of these little monsters every season, so be prepared.
How to Get Rid of Tomato Hornworms
The best way to get rid of tomato hornworms is to combine both control and preventive measures; this will give your plants a survival chance than trying to keep up with them when they have eaten your plants halfway.
A single green horned tomato worm is capable of consuming all of your plant’s leaves in a short period.
This sizeable green caterpillar has a greedy appetite and eats all round the clock, hence why they grow very quickly and mainly in size.
They can become as large as five to six inches in length and one inch in circumference.
Here are a few ways to get rid of these pests:
Handpicking is a good tactic and the most natural way to control these menace if you have the time and patience or manage a small tomato garden.
The good thing is that tomato hornworms are not dangerous – they neither bites nor sting humans, and they are easily spotted on the vine since they are larger versions of the caterpillar.
So, you can quickly grab them and remove them by hand to get them off of your plants.
The best way to identify these hornworms on tomatoes is to thoroughly check the plant’s leaves and stems from top and bottom 2-3 times a day.
Note that they are also green in color and does a perfect job of fitting into plants, so look closely and carefully.
Thoroughly check your plants every day for an indication of these pests.
These indications include:
Caterpillars, Chewed leaves, frass, and eggs.
Handpick and place them in a bucket of soap water or feed them to your chicken. Handpicking is the safest and cheapest method on how to get rid of tomato hornworms.
TIP: Ensure to put on hand gloves when handpicking tomato hornworms from the garden because they exhibit a defensive mechanism that makes them spit “tobacco juice” (dark brown liquid) onto your hand.
Interplanting with Beneficial Companions
Interplanting particular plants with tomatoes will help to deter the sphinx moth from laying her eggs on your garden tomatoes.
These plants are effective in repelling tomato hornworms.
But what plants repel tomato hornworms?
Some of the companion plants that do well in repelling tomato hornworms are:
Borage: They help to inhibit the reproduction of eggs by hornworms by making the environment inconvenient.
Borage plants also attract predatory wasps and beneficial insects, which help in destroying hornworm present.
Marigolds: The marigold plant attracts all kinds of beneficial insects, including parasitic wasps, and it gives off a repelling aroma that sets off the caterpillar and prevents them from moving in.
The best types of marigolds to use are Calendula (often called Pot Marigold) and the Tagetes (Grannies Garden variety) marigold.
Basil: Planting basil near your tomatoes will serve as a flavor enhancer to them while at the same time repelling tomato hornworms.
There are also edible plants with blossoms that also attract the Braconid Wasp:
- Nasturtiums – these are also edible.
Using ground cover mulch will reduce the pest infestation by preventing them from creeping their way to the surface of the plants.
The reproductive cycle is interrupted when the moth is kept in the ground, as the moths have nowhere to feed and will eventually die before laying new eggs.
Using Beneficial Insects
Beneficial insects are also known as predatory wasps; they are very important biological control gardeners always have handy.
These beneficial insects play a significant role in the tomato hornworm control.
They usually lay their eggs inside or on top of the hornworm, and when the wasp larva hatch, they will destroy the hookworm without harming your plants.
Examples are Trichogramma wasps, lacewings, and ladybugs.
Use a DIY natural homemade solution
You can prepare a homemade natural solution to keep hornworms at bay.
To make, combine water and mild liquid dish soap in a spray bottle and spray the plants and worms until appropriately covered.
This should be enough to get rid of the tomato hornworms without causing any further harm to your garden plants and beneficial insects.
Some growers also claim to use cayenne pepper with the natural soap solution.
By covering the outer parts of the plants with a bit of cayenne pepper, as this may cause further discomfort to the worms.
Also, just in case the rain comes and washes away the soap/water combination before eliminating the pests.
Using Insecticide to Control Tomato Hornworms
When the applied methods fail to get rid of this pest, an insecticide can be used as a last resort.
It is best to go for organic Insecticides because they are products formulated using natural products and are a much safer choice for the rest of your plants and beneficial insects.
Read Also: Can I Plant Cucumber and Tomatoes Together?
Finding these little moths feeding off your tomatoes is frustrating, but that is not enough reason to get worked over.
When next you see signs of tomato hornworms or approach their season, take immediate action by using these methods provided on how to get rid of tomato hornworms, and they will be taken care of, never to return.
It is also important you try out all varieties of control measures provided in this article to prevent built-in resistance by these hornworms.