Green Caterpillars on Tomato Plants (Tomato Hornworms) – Identification and Control

The horn-like tail of the tomato hornworm, a gigantic green caterpillar, wreaks havoc on tomato plants. Creamy-white V-shaped patterns down the sides of the hornworms are unique. The harmful caterpillars, on the other hand, owing to their green hue and tendency to blend in with tomato foliage, may be difficult to detect on tomato plants.

It’s difficult to get rid of tomato hornworms for good. The enormous fat green worm-like insects can be spotted with patience and vigilance. The most common technique to get rid of caterpillars is usually hand-picking them and dropping them in soap water. Tomato hornworms can be prevented or controlled in a variety of ways, though.

This article will teach you how to identify and distinguish fat green caterpillars from tomato plants. Before they do too much damage, pictures and descriptions of the pale green hornworms may help you spot them. You’ll also learn helpful ways to get rid of hornworms for good.

How to Identify Tomato Hornworms (Manduca quinquemaculata)

Tomato hornworms are huge caterpillars with green bodies, a blue black tail-like horn, and white V-shaped markings on either side. Hornworms as large as 5 inches (127 mm) long have been seen. They have an expanded head that is curled inward and five pairs of enormous prolegs on their center segments.

The black or dark blue pointed protrusion at the tail of tomato hornworms gives them their name. The tomato hornworm is distinguished from the tobacco hornworm by its coloration at the tail end. The tobacco hornworm has a reddish, horned tail, whereas the tomato hornworm’s tail is dark blue.

The V-shaped yellowish-white stripe along the sides of the pale green tomato hornworm is another way to identify it. On the apex of the white V-shape, you may see tiny eye-like markings. To help protect itself from predators, it has eyespots on either side of its head.

Since they blend in well with their surroundings, identifying tomato hornworms on plants might be difficult. You may safely remove the caterpillar by hand if you notice one beneath the leaves or crawling on the stems. Despite their stinger-like tail, tomato hornworms are harmless to humans and will not sting them.


Tomato Hornworm Vs. Tobacco Hornworm

The tomato hornworm (Manduca quinquemaculata) and the tobacco hornworm (Manduca sexta) both appear to be similar in appearance. The tail color and markings are what set the two apart. The tomato hornworm’s tail is dark blue-black instead of reddish, and it does not have a horn. In addition, unlike the tomato hornworm, the tobacco hornworm has diagonal patterns on its side.

Life Cycle of Tomato Hornworms

The egg, caterpillar (larva), pupa, and adult moth are the four phases of the tomato hornworm life cycle. After the female lays the eggs, they hatch around seven days later. The adult moths live for 10 to 30 days after the caterpillars hatch and grow up to full size in four weeks.

Hornworm eggs, which are approximately 0.039″ (1 mm) in diameter, are tiny, pale green to white oval balls. The larvae feed on tomato plant leaves after the eggs hatch in late spring. They shed their skin and grow up to 4″ or 5″ (100 – 127 mm) during each of the five instars (growth stages).

Tomato hornworms, which have a voracious appetite throughout their larval stage, typically remain on the same plant and devour the leaves. The tomato hornworm keeps its defining characteristics throughout the majority of its larval stages, including creamy white V-marks and a black horn tail.

When the tomato hornworm goes underground to pupate, it reaches the third stage of its life cycle. A huge, reddish-brown segmented cigar-like item with a loop at one end is the pupa. The tomato hornworm becomes the five-spotted hawkmoth after emerging from its pupa. The wingspan of this huge brown and gray moth is 5 inches (13 cm).

Manduca quinquemaculata is a five-spotted hawkmoth.

Tomato Hornworm Damage

The tomato hornworm, which can devour leaves on an entire plant in just a few hours, exemplifies the name of the group. The pests may sometimes assault the tomato’s fruit, causing severe scars. Eggplant, potato, tobacco, and pepper leaves are all members of the nightshade family Solanaceae, which these hungry caterpillars will devour.

Tomato hornworms, on the other hand, are not dangerous to humans. Without the risk of being stung, you may safely pick them up. Green hornworms won’t bite humans, and their black tail isn’t a stinger, despite their insatiable appetite. As a result, preventing damage is best done by physically removing them. How do you know if tomato hornworms are attacking your greenhouse plants? The enormous caterpillars have eaten your tomato plants if you see any of the following symptoms.

Tomato hornworms destroy leaves

Holes appearing in your tomato plant leaves are the first indication of tomato hornworm damage. This is most commonly seen in late spring, when the harmful larvae have hatched. Unfortunately, since they are so tiny, it’s difficult to see them after they’ve hatched.

The plant-killing “buggers” progressively strip the top leaves from a tomato stalk as they develop. Devoured blossoms, full defoliation, and open wounds on tomato fruits are other signs of tomato hornworm activity. In a day, the hungry caterpillar can devour a 1-foot (30 cm) long tomato leaf.

Tomato hornworm droppings

Tomato hornworm droppings appear to be dark green or black dry, crumble-like barrel-shaped things. Little coffee beans or black pellets look like tomato hornworm droppings. The black or green droppings on the top of the leaves will show if the hornworms are harming the plant.

Tomato hornworm damage fruits

Unfortunately, tomato caterpillar infestation can be found even among your precious tomatoes: fully ripe or partially ripe. Caterpillars may begin devouring tomatoes in their last instar. They’ll devour the skin and much of the meat, leaving tomatoes with massive, deep scars. In a short amount of time, a huge tomato hornworm can consume many tomatoes.

How to Protect Plants From Tomato Hornworms

When it comes to protecting tomato plants from hornworms, prevention is critical. Tomato leaves, for example, should be inspected for signs of eggs and wiped down to remove them. The little light oval eggs, on the other hand, are quite tiny. This may not always be effective. Checking the plants every few days for nasty bugs is the most common way to protect tomatoes from caterpillar activity. Despite their camouflage, they stand out because of their enormous size.

How to Control Tomato Hornworm

A multi-faceted strategy is required to keep tomato hornworms away from your greenhouse veggies and tomatoes. In most situations, organic methods are the best way to manage tomato caterpillar populations. This prevents the voracious larvae from gaining resistance to pesticides by lowering their exposure to harmful and toxic chemicals. Several gardeners have reported that employing the following techniques has helped them manage tomato hornworms.

Beneficial insects are effective for tomato hornworm control

Hornworm suppression is helped by predatory insects like ladybugs, green lacewings, trichogramma parasitic wasps, and braconid wasps. Before they have a chance to do harm, the beneficial insects feed on Caterpillar eggs and larvae. Tomato hornworms are also parasitized by beneficial insects.

Wasps that parasitize larvae, for example, lay their eggs inside them. Before pupating, the eggs devour the hornworm’s innards inside caterpillars. Little grains of white rice glued to the caterpillar are larval pupae. The awful tomato hornworm is killed by adult wasps when they hatch.

It is therefore recommended to leave the caterpillar alone if you discover a tomato hornworm on your plants and have numerous tiny white sacs connected. The weakened caterpillar will be killed by the parasitoid wasps soon after they hatch. Then, they’ll seek out additional caterpillars to parasitize and hornworm-free plants.

Have good weed control practices to control tomato hornworms

A excellent strategy to get rid of tomato hornworms from your lawn is to till the land in the fall. After harvest, caterpillars burrow into the ground to overwinter, which makes this control method useful. Tilling before you plant new tomatoes will interrupt the caterpillar’s life cycle, killing most of the larvae in the soil.

Crop rotation for tomato hornworm control

Rotating crops every other year is a tried and tested method for organic pest control. If you had tomato hornworms the previous year, this cultural control technique is worth trying. After that, all you have to do is relocate your tomatoes. This protects overwintering hornworms from depositing their eggs on plants.

Mulch can help prevent tomato hornworm larvae from emerging

Mulch can help keep the destructive caterpillars at bay by covering your newly-planted tomato plants in a thick layer. The larvae are prevented from emerging from the ground and depositing eggs on your nightshade plants by mulch. To create a solid barrier, some gardeners recommend black plastic.

A thick layer of straw can also be laid down. Mulching has a general positive impact on your crops. Organic mulch may help retain moisture and prevent weeds from growing by protecting the ground surface. Of course, you’ll also be able to prevent nasty overwintering soil insects.

How to Get Rid of Tomato Hornworms

Relocating large fat tomato caterpillars manually is the simplest way to get rid of them from your plants. However, throughout the majority of the tomato hornworm life cycle, there are methods to eliminate them. Natural insecticides, such as bacillus thuringiensis, neem oil, and insecticidal soap, can be used to combat hornworm eggs and larvae when they are first deposited.

Handpick tomato hornworms to eradicate them

The most common technique to kill tomato hornworms is by hand removal. Despite their camouflage function, large insects may generally be detected during a close examination. Hornets won’t sting or bite, so they’re completely harmless. To destroy them, pick up each one and toss it into a hot soapy water bucket. To reduce plant damage in your greenhouse or yard, check for tomato hornworms twice weekly.

Neem oil kills tomato hornworm eggs and tiny larvae

In your battle with the green beasties, spraying neem oil can be one of your practical tools. Because it contains a natural insecticide, neem oil kills caterpillars by interrupting their life cycle. Larvae development and growth are both inhibited by neem oil spray. The caterpillar eggs and larvae die as they age.

Mix 2 tsp. neem oil with 1 gallon of water and apply to your tomato plants. 1 quart (1 l) of water and 1 tsp of neem oil. Spray your tomato plant leaves liberally with the neem oil solution in a spray bottle. Until all evidence of caterpillar activity has vanished, apply the natural pesticide every seven days.

You should begin using neem oil early in the season, when you are trying to kill tomato hornworm eggs and emerging larvae, for it to be effective. If you want to eliminate hornworms from tomato plants completely, however, combining the neem oil spray with other hornworm control methods is crucial.

Insecticidal soap kills tomato hornworms

Another effective way to kill tomato hornworms is to spray insecticidal soap on them. Insecticidal soap is a natural insecticide that stops tiny larvae from developing by suffocating them and destroying their protective outer layer. As a result of this, the caterpillars die as a consequence of being dehydrated by the soap residue. Furthermore, to cleanse tomato plant leaves of eggs, insecticidal soap is effective.

A brand like Dr. Turtle might be used to create a soap spray. Ivory Snow or Bronner is a good choice. For every gallon (3.4 l) of liquid, you should use between three and six tablespoons. Spray both sides of the leaves and any visible caterpillars with the solution after mixing the soap and water. To be successful, insecticidal soap must be applied to the pests. You can alternatively purchase commercially made organic insecticidal soap to kill tomato hornworms.

Bacillus thuringiensis (Bt) gets rid of tomato hornworms

Getting rid of bothersome tomato caterpillars for good may be helped by using a low-risk natural pesticide like bacillus thuringiensis (Bt). Bacillus thuringiensis var. is the bacteria strain to use. The kurstaki is a caterpillar-hunting device. You purchase the Bt product and use it according to the manufacturer’s advice.

Bacillus thuringiensis is a benign soil microbe that does not harm plants or other insects. The solution only works if the caterpillars consume it, and it is most effective on caterpillars measuring less than 2 inches (50 mm). As a result, you should apply the solution to the tomato plant’s foliage, particularly on the underside of leaves.

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