Tomato hornworms can cause serious damage to your garden by chewing through your tomato plants. These large, green caterpillars, which are the larvae of the five-spotted hawk moth, eat voraciously and can quickly strip your plants bare.
Their green color helps them blend in with the leaves, making them hard to spot, and their feeding can seriously harm your crops. In this article, we will go over practical ways how to get rid of tomato hornworms so you can keep your garden in top shape.
What are Tomato Hornworms
Tomato hornworms are large, green caterpillars that grow up to 5 inches long. They are the larvae of the five-spotted hawk moth, a brown and gray moth. The hornworms have a distinctive horn-like projection at their rear end, which is why they’re called hornworms.
These caterpillars are known for their strong appetite and mainly feed on tomato plants, but they can also munch on other nightshade plants like eggplants, peppers, and potatoes.
They usually eat at night, making them hard to find during the day. Hornworms start eating from the top of the plant and work their way down, often causing severe damage by chewing on stems and even fruits.
Damages Caused by Tomato Hornworms
Tomato hornworms can cause significant damage to your garden. Their feeding habits primarily affect tomato plants but can harm other nightshades like eggplants and peppers. Here is how they can damage your plants:
Leaf Loss
Tomato hornworms eat large amounts of the plant's leaves, which result in serious leaf damage. As they munch on the foliage, they take away the plant’s ability to make food through photosynthesis. This means the plant cannot produce enough energy to grow properly and produce fruit.
With fewer leaves, the plant cannot capture sunlight and convert it into nutrients. This weakens the plants, making them more susceptible to diseases and pests. Therefore, it is important to manage hornworm infestations to prevent this damage and keep your plants healthy.
Tomato hornworms can cause serious harm by boring holes into tomatoes. They chew through the fruit, creating deep holes in the tomatoes, disrupting their development. The entry points create visible wounds and introduce pathogens and diseases, as the damaged fruits are more vulnerable to infections.
These damaged tomatoes become unsightly and may not be safe to eat. This not only reduces the quality of your harvest but also cuts down the amount of good fruit you can collect.
Reduced Growth
When tomato hornworms eat the leaves of a plant, they disrupt its growth. Leaves are crucial for making energy through photosynthesis, so without enough leaves, the plant cannot grow properly. This will stunt its growth and development, which can lead to smaller plants that are less robust and less capable of supporting a healthy crop.
The loss of leaves also makes the plant more vulnerable to other pests and stresses, leading to further problems. So, the damage from hornworms can seriously affect the plant’s health and productivity.
Lower Yields
Hornworms can greatly reduce your tomato harvest by damaging the plant and its fruits. When they eat the leaves, the plant cannot make as much food for itself, which means it will not produce as many tomatoes.
Plus, the holes they chew into the fruits can cause problems like rot and make the tomatoes fall off the plant early. This damage leads to fewer tomatoes and lower-quality produce, reducing the harvest.
Plant Stress
When tomato hornworms damage plants, it causes more problems than just visible harm. By eating the leaves and fruits, hornworms reduce the plant’s ability to make food and energy. This makes the plant weaker and less able to defend itself from pests and diseases.
A stressed plant may grow slower and become more vulnerable to problems like bad weather or infections. Taking care of hornworm issues quickly helps the plant stay healthy and strong, making it better able to recover and keep producing.
Neem oil is a natural insecticide derived from the seeds of the neem tree. To use neem oil against tomato hornworms, mix 2 tablespoons of neem oil with 1 tablespoon of mild liquid soap and 1 gallon of water. Pour the mixture into a spray bottle and thoroughly spray all plant surfaces, including the undersides of leaves.
The neem oil disrupts the hornworms' feeding and growth, making it harder for them to thrive. Apply the solution every 7 to 14 days, especially after rain, to maintain effectiveness. Neem oil is safe for beneficial insects and the environment when used properly.
2. Handpicking
Handpicking tomato hornworms involves a hands-on approach where you visually inspect your tomato plants for pests. Hornworms are large, green caterpillars that blend in with the foliage, so look carefully on the undersides of leaves and along stems.
Once spotted, gently grasp the hornworm and remove it from the plant. Drop it into a container of soapy water to kill it. This method is effective for small infestations and allows immediate control without chemicals. Regular inspections and prompt removal can significantly reduce hornworm damage and keep your plants healthy.
3. Diatomaceous Earth
Diatomaceous earth (DE) is a natural, powdery substance made from the fossilized remains of tiny aquatic organisms called diatoms. It is an effective pest control method due to its abrasive texture and high silica content. When you sprinkle DE around your tomato plants, it sticks to the hornworms and other pests that crawl through it.
The powder damages their exoskeletons, causing them to dehydrate and die. For best results, apply DE in dry conditions, reapply after heavy rain or watering, and ensure it covers the soil surface around your plants. Wear a mask to avoid inhaling the fine particles during application.
4. Bacillus thuringiensis (Bt)
Bacillus thuringiensis (Bt) is a natural bacteria that helps control tomato hornworms. To use it, buy a Bt product designed for caterpillars. It can be purchased as a liquid concentrate, powder, or granules. Mix the powder with water as directed on the label and spray it onto your plants.
When hornworms eat the treated leaves, the bacteria makes them sick and they die. Bt only affects caterpillars, so it will not harm other helpful insects. For the best results, apply Bt early when you first notice hornworms.
Using predatory insects like trichogramma wasps or braconid wasps can help control tomato hornworms naturally. Trichogramma wasps lay their eggs inside hornworm eggs, stopping them from hatching. Braconid wasps lay their eggs inside hornworm larvae, which then eat the hornworm and kill it.
To use this method, buy these beneficial insects from a garden store and release them in your garden following the instructions. Timing is important, so remember to release them when hornworms are active for the best results.
6. Row Covers
Row covers are thin fabrics you place over plants to keep pests like tomato hornworms away. They act like a shield, letting sunlight and rain through while keeping bugs out. To use them, set up hoops or stakes over your plants to hold the fabric up, then drape the cover over these supports.
Secure the edges with soil, rocks, or clips to keep them in place. Check your plants regularly to ensure the cover is working, and adjust it as needed. Row covers help protect your plants and keep hornworms at bay.
7. Companion Planting
Companion planting means growing certain plants next to your tomatoes to keep hornworms away. For example, basil has a strong smell that masks the scent of tomato plants and confuses hornworms, making it harder for them to find your tomatoes.
Marigolds also repel many hornworms by producing compounds in their foliage and flowers. To use this method, plant basil and marigolds around your tomato plants or mix them with your tomatoes. This method creates a natural barrier that helps protect your tomatoes from hornworms.
8. Organic Pesticides
Organic pesticides containing spinosad are effective against tomato hornworms due to their ability to disrupt the pests' nervous systems. Spinosad is derived from natural sources and targets the insects' nervous system, causing paralysis and death.
To use it, mix the spinosad with water as directed on the label and spray it on your plants, covering all the leaves where hornworms might be eating. It is safe for helpful insects and has little impact on the environment. You may need to reapply it, especially after rain, to keep it working effectively.
9. Soap and Water
One of the more simple yet cost-effective methods to combat tomato hornworms would be using a soap and water solution. The soap breaks down the outer layer of the worms' bodies, causing them to dry out and die.
To apply this method, mix a few tablespoons of mild dish soap with a quart of water in a spray bottle and spray it directly on the hornworms. Remember to cover them completely. Reapply every few days or after it rains to keep it working. This method is gentle on plants and will not harm beneficial insects when used properly.
Crop rotation can be a way to keep hornworms in check. When you keep planting tomatoes in the same spot, hornworms thrive in the soil. By changing where you plant your tomatoes each season, you disrupt their lifecycle.
For example, after you finish growing tomatoes, switch to something else, like beans or lettuce in that area. This makes it harder for hornworms to find their favorite food. Plan your garden layout to avoid planting tomatoes or other related plants in the same place for at least two years.
11. Garlic Spray
Garlic spray can help keep tomato hornworms away because they dislike the pungent smell of garlic. To make it, blend a few garlic cloves with water, strain out the solids, and mix a bit of dish soap to help the solution stick to your plants.
Spray this mixture all over your tomato plants, especially where you see hornworms. The garlic's smell confuses and repels the pests. Reapply the spray after rain or once a week to keep it effective.
12. Hot Pepper Spray
Hot pepper spray is an effective and natural way to deter tomato hornworms. The capsaicin in hot peppers creates an unpleasant sensation for pests, making the plants less appealing. To make hot pepper spray, blend a few hot peppers with water, then strain the mixture to remove solids.
Add a few drops of dish soap to help the spray adhere to the leaves. Transfer the solution to a spray bottle and apply it directly to the affected plants, focusing on the areas where hornworms are likely to feed.
13. Tobacco Tea
Tobacco tea is an effective trick for dealing with hornworms, thanks to nicotine’s ability to disrupt their nervous systems. To make it, steep a handful of tobacco leaves in hot water for a day. After it cools, strain out the leaves and pour the liquid into a spray bottle.
Spritz this solution on your plants to repel the hornworms. Just be mindful that it can also affect helpful insects, so it is best to apply it when fewer beneficial bugs are around, like early in the morning or late in the evening.
14. Handheld Vacuum
Using a handheld vacuum to remove tomato hornworms is another effective method. Bring the vacuum nozzle close to the hornworms on your plants and turn it on. The suction will pull the hornworms off the plants and into the vacuum.
This technique works well because it targets the pests directly without damaging your plants. It's best to do this in the morning or evening when the hornworms are less active. Make sure to empty the vacuum regularly and dispose of the hornworms to keep your garden pest-free.
Proper watering helps keep tomato hornworms away by ensuring your plants stay healthy. If you water too much, it creates a damp environment that attracts pests and diseases. Instead, water your plants deeply but less often, letting the soil dry out a bit between waterings.
This watering practice keeps your plants strong and makes it less likely for hornworms to show up. Stick to a regular watering routine based on your plant's needs and the weather to keep your garden in good shape and reduce pest problems.
16. Clean Debris
Cleaning up plant debris is key to controlling hornworms. These pests often hide in fallen leaves and plant scraps, making it easy for them to go unnoticed. By regularly removing this debris, you reduce their hiding spots and make your garden less inviting for them.
Just rake up and get rid of dead leaves, broken branches, and other organic matter around your plants. This simple task not only clears away potential hornworm shelters but also keeps your garden cleaner and less appealing to pests.
17. Traps
Using traps with pheromone lures is a smart way to deal with hornworms. These traps attract adult moths, which are the ones that lay the eggs for hornworms. Simply set up the traps in areas where you have seen hornworms or where you think they might show up.
The moths will be drawn to the pheromones and get stuck in the trap, which helps lower the number of eggs laid and, in turn, reduces the hornworm problem on your plants. It is a good way to get ahead of the issue and keep your garden healthier.
18. Encourage Birds
Attracting birds to your garden is a great way to deal with hornworms. Birds like chickadees and bluejays naturally eat hornworms, so having them around can help control the problem. To make your garden bird-friendly, set up bird feeders, baths, and houses, and plant native shrubs and trees.
This creates a welcoming environment for birds, giving them food and shelter. Keep feeders stocked and water fresh to keep birds coming back, which will help keep those pesky hornworms in check.
If you are dealing with a severe hornworm infestation and need expert help, calling a professional pest control service can be a good option. These experts can assess the situation, use advanced treatments, and provide advice on preventing future problems.
They might apply targeted pesticides or introduce beneficial insects to manage the pests effectively. Plus, professionals can help identify any other underlying issues contributing to the infestation. This approach can save you time and effort, ensuring your garden gets the attention it needs to recover and thrive.
20. Regular Monitoring
Regular monitoring means checking your plants often to spot hornworms before they cause too much damage. Make it a habit to look under leaves and along stems, especially during the season when hornworms are most active.
Look for the big green caterpillars or their droppings. If you find them early, you can pick them off by hand or use other methods to deal with them. Staying on top of this will help keep your plants healthy and free from major pest problems.
Types of Tomato Hornworms
There are two main types of tomato hornworms you might find in your garden. Both types are known for their heavy feeding and can cause a lot of damage to tomato plants by eating leaves, stems, and fruits. Here is an overview
Five-Spotted Hawk Moth Hornworms: These are green caterpillars with white and black diagonal stripes and five white spots on each side. They can grow up to 4 inches long and turn into moths known as five-spotted hawk moths.
Two-Spotted Hawk Moth Hornworms: These are also green but have a reddish or purple horn on their tail and two prominent white spots on each side. They’re often called tobacco hornworms and become moths known as Carolina sphinx moths.
