Common Tomato Plant Pests and How to Fight Them Organically

By Bethany Hayes

Tomato plants are an iconic vegetable plant that everyone adds to their garden, but pests love them as much as gardeners. Gardeners often find that pests love to stop and munch on their tomatoes, destroying plants and entire harvests. Learning how to treat tomato plant pests organically is essential for all gardeners.

Keeping a garden free of tomato pests without the use of harmful chemicals is challenging. Producing the perfect tomato means gardeners have to keep an eye out for insects and any sign of a pest problem. Reacting quickly eliminates pests before they eat all of your plants.

Remember, not all insects in your garden are harmful. Before you reach for the nearest pesticide, take time to learn what each insect in your garden is and why it’s there. Some insects are harmful and destroy crops, while others might be feeding on the very pests destroying your garden. 

10 Tomato Plant Pests and How to Get Rid of Them Organically

Tomato plants face many different pests. It’s impossible to name all of them because they vary based on location. Each continent faces various insects and problems. These ten tomato pests are the most common ones that gardeners face. 

Cutworms

Cutworms are a common tomato plant pest that feeds on the seedlings and plants at night. As their name suggests, these pests “cut” through the stems or an inch above the soil. Cutworm damage varies but often leads to the death of the plant, cutting it right in half. 

How to Identify Cutworms

Despite the name, cutworms aren’t truly worms. Instead, they’re moth larvae that emerge at night only. That makes it hard to spot and identify them. You won’t spot them in the daylight. 

Cutworms look like little grubs you might find when you dig in the soil. What they look like will depend on the moth species. Cutworms vary in colors and can be pink, green, brown, or black. Most have muted stripes running the length of their bodies. 

When disturbed, cutworms curl up into a “C” form. In most cases, cutworms are black or grayish-brown, measuring two inches in length. 

Common Signs of a Cutworm Infestation

Since cutworms like to come out at night, it’s hard to identify them. Look for signs of damage caused by cutworms.

• Damaged stems 
• Severed stems 
• Small tunneling holes in the garden or lawn

How to Get Rid of Cutworms Organically

The best thing to do is to prevent cutworms rather than get rid of them. 

1. Make a Collar

Make a collar that fits around your seedlings base out of either newspaper, cardboard, or aluminum foil. It should be one to two inches wide; it needs to go one-inch into the ground to protect the roots. 

Once the plant has several sets of real leaves, remove the collar. 

2. Spread Cornmeal

Another trick that you can try is to spread cornmeal around the base of your plants. Cutworms die after eating cornmeal. 

3. Clear Away Debris

Take away all the dead plant material in the winter because cutworms overwinter in these materials. Cleaning up your garden helps to reduce their population. 

Aphids

One of the tiniest pests that infect tomato plants is aphids. They gather as dense clusters on your plants, typically the stems or new growth. Small numbers of aphids aren’t a big deal and nothing to stress over, but a large infestation will damage or kill your plants.

The damage to plants comes in twofold. First, aphids suck the sap out of the shoots and leaves and inject saliva into the plant to spread diseases. Then, they excrete a sticky substance called honeydew that encourages the development of sooty mold. 

When plants have sooty mold, it develops across the entire plant and prevents the process of photosynthesis. 

How to Identify Aphids

Identifying individual aphids is difficult, if not impossible, because they’re so small. The good thing is that aphids rarely, if ever, are separate; there will always be more than one grouped in clusters. Gardeners refer to them as plant lice; they’re that small. 

Here are things to look for when identifying aphids.

• Small, measuring 1/10th of an inch
• Typically green and black, but their colors could be brown, reddish-brown, and gray, depending on your location. 
• Two long tubular appendages come out at the tail end of their bodies. 

Signs of an Aphids Infestation

Typical signs of an aphids infestation include:

• A sticky substance on the leaves
• Ants covering the plant, attracted to the honeydew.

How to Get Rid of Aphids Organically 

Unless dealing with a large infestation, aphids rarely cause significant damage. That doesn’t mean you should let them live freely in your garden. If you find aphids, take care of them, but don’t stress or consider any chemicals unless damage appears.

1. Knock Them Off with Water

The first step is to remove them from the plants. Most people use a jet of water from the garden hose to do this, so spray the clusters and get them off your plant. For small infestations, this step is all that’s typically needed. 

2. Pinch Off Foliage

If knocking them off with water isn’t enough of a deterrent, pinch off the foliage where you find the most densely concentrated aphids. Toss those into a trash bag; never put them in the compost or on the ground. 

3. Release Beneficial Insects

If the infestation is bigger than you thought, the next step is to release beneficial insects into your garden. Lacewings and ladybugs are the two beneficial insects that love to munch on aphids. 

4. Use Insecticidal Soap 

Another option is to use insecticidal soap made of natural fats and plant oils. Insecticidal sprays work as well, so long as you pick a natural spray. 

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Blister Beetles

Blister beetles are part of the Meloidae family, and each region throughout the United States has a different species. It’s most common to find these pests in the east, south, and midwest. 

Most people know about blister beetles because they can harm humans. When injured or crushed, these beetles release a blistering agent called cantharidin, hence their name. No one likes to have blisters on their skin.

Blister beetles pose a threat to your tomato plants, swarming, and arriving in large numbers. 

Identifying Blister Beetles

Since there are many species, their size and coloring vary. Most are one-half to one inch long with soft bodies and broad heads. Their antennae are a third of their body length. 

Coloring varies, but it’s typically bright and variegated or striped. Some are shades of grey and brown with yellow stripes. 

Signs of Blister Beetles

Aside from blisters and skin rashes, look for other signs of these pests in your garden. The most common symptoms are holes throughout the foliage as these are chewing beetles.

Getting Rid of Blister Beetles

Removing blister beetles by hand is usually the first course of action, but be careful and wear gloves to protect your skin. If you have a larger infestation, here are a few things to try.

1. Cover with Row Covers

If you have a large swarm, covering your plants with row covers can protect them. Make sure they’re well-anchored without access spots. 

2. Attract Birds

Birds love to munch on blister beetles, so attracting birds with well-placed feeders and water can reduce the population.

3. Use a Biopesticide

If you feel that the infestation is bad enough to require a spray, look for a biopesticide. Spinosad is one that’s known for being effective against these pests. 

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Tomato Hornworms

Hornworms are an iconic tomato plant pest. It’s one of the easiest pests to identify while also being one of the most destructive insects. Tomato hornworms destroy a mature tomato plant in a single night, so it’s vital to stay alert to their presence. 

How to Identify Hornworms

Hornworms are easy to identify. If you find a large, green worm that measures two to three inches long in your garden, chances are it’s a hornworm. They have small horns on top of their head and ridged, segmented bodies. Some can be half the width of your palm.

Despite their size, hornworms are a pale-green color, blending into their surroundings well. It’s easy to mistake them for a tomato stem or branch. Close inspection is needed, and since they typically emerge at night to eat, identification is tricky. 

Signs of Hornworms

These pests eat non-stop, so the most apparent sign is considerable defoliation in a short timeframe. The leaves will look spotted and chewed. Sometimes, hornworms eat the fruit as well. 

How to Get Rid of Hornworms

Don’t resort to chemicals to kill tomato hornworms. There are several organic pest control methods to try first. 

1. Parasitic Wasp

Releasing parasitic wasps into your garden is nature’s way to get rid of tomato hornworms. These wasps lay eggs on the hornworm’s body, and as they start to hatch, the wasps eat the worm alive. It takes time, but parasitic wasps kill these pests without the use of chemicals. 

2. Companion Planting

A simple trick to remember when planting your garden is to add marigolds around the tomato plants. Marigolds look beautiful while also having a strong scent that repels hornworms naturally. 

3. Use B.T. Sprays

Look for a spray that contains B.T., which is a naturally occurring fungus that stops hornworms without harming earthworms at the same time.

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Colorado Potato Beetle

Colorado Potato Beetles are native to the United States and enjoy eating all plants in the nightshade family, including potatoes and tomatoes. Their first choice is potatoes, but if they can’t find those in your garden, the next stop is tomato plants, along with eggplants and peppers. 

Despite their name, these pests live in nearly every state throughout the United States. Exceptions are California, Nevada, Alaska, and Hawaii. 

How to Identify Colorado Potato Beetles

These beetles are close to the size of a dime with yellow and black striped wings. Look for the ten alternating yellow and black stripes on their shells. That’s a clear indicator. 

The females lay clusters of gold or yellow eggs on the underside of leaves. Once the larvae hatch, they move out in the tomato leaves. It’s easy to spot the larvae; they’re red to dark pink with dark, black spots. Look under the leaves throughout the day to spot them. 

Signs of Colorado Potato Beetles

Both the adults and larvae are voracious eaters, quickly defoliating the plants leading to stunted growth. Here are some signs left by these pests.

• Damage starts at the new foliage tips, followed by whole leaves.
• Skeletonized leaves with only the veins remaining 
• Plants might die.
• Stunted fruiting

How to Get Rid of Colorado Potato Beetles

Once you discover Colorado potato beetles, it’s time to get rid of them. Hand removal is the first choice; wear gloves when doing so.  Here are some options.

1. Pyrethrin Pesticides

These pests can be tricky, so using a pesticide that contains pyrethrins is an excellent choice. It’s best to use this method in the early spring before the larvae mature. 

2. Confuse with Non-Host Plants

One method of prevention is planting non-host plants around your tomato plants. This can confuse these beetles and delay an infestation.

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Flea Beetles

Don’t let their looks deceive you; flea beetles carry the possibility of severe destruction. The problem with these little pests is that they attack all aspects of your plant. The adult flea beetles eat the leaves and foliage, while the larvae stay in the ground, eating the roots. 

Flea beetles attack all types of plants in your garden. Not only will they eat tomato plants, but cabbage, corn, lettuce, potatoes, and peppers are all vulnerable to attacks. 

How to Identify Flea Beetles

Flea beetles are named such because they resemble and jump like a flea that you might find on your dog. Here is what to look for when identifying flea beetles.

• Large back legs 
• Black, bronze, bluish, or brown
• Some have stripes. 

Signs of a Flea Beetle Infestation

These pests’ main signs are small holes in leaves; these pests love to chew on leaves. Sometimes, they might feed on mature fruits, but it’s unlikely. 

How to Get Rid of Flea Beetles

Unless the flea beetle population is high, most damage is minimal. Gardeners must focus on preventative measures and keeping their numbers low. Prevention is key to stopping flea beetles from destroying your tomato plants. 

1. Clear Away Debris

The first step to preventing flea beetles is to clear out weeds and debris that might gather in your garden, in particular during the winter. Debris gives adult flea beetles a place to hide in the cold weather.

2. Trap Them

Since the adults jump and fly around, putting out sticky traps is an easy method to capture them. It also helps you monitor their population; the more you catch, the larger the population is. 

3. Use Row Covers

In the spring, using row cover over your young plants and seedlings protects them from the beetles. Row covers also stop the adults from laying eggs in the soil. 

4. Dust with Diatomaceous Earth

If you notice the adults flying around, dusting the plants with diatomaceous earth helps stop them from feeding on the leaves and stems. 

5. Use Botanical Insecticides

For bad infestations, gardeners turn to botanical insecticides, such as pyrethrin, to control the pests. 

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Nematodes

Without a doubt, one of the most dreaded tomato pests is nematodes. There are over 20,000 different nematode species, and most are microscopic worms in the soil. Only a few are problematic for gardeners; most you want to have in your garden!

For example, insect pathogenic nematodes control other pest problems, such as fungus gnats or flea beetles. The problematic species is most often the root-knot nematode.

Root-knot nematodes are no joke. They cause bumps or galls that reduce or stop the plant’s ability to bring up nutrients through the stem and prevents the plant from performing photosynthesis. That’s essential for your plant to live, so these nematodes can kill plants in no time. 

Signs of a Nematode Infestation

Root-knot nematodes live in the soil, so the signs start underground. Nematodes are microscopic, so the only way to identify them is to look for the typical signs a problem is happening. Some typical symptoms include:

• Stunted growth
• Yellowing leaves
• Unusual growths on the roots 

How to Get Rid of Nematodes

Controlling nematodes, once in your garden, is relatively difficult, if not impossible. That’s why prevention truly is critical. Here are some suggestions. 

1. Rotate Crops

Nematodes take time to establish in the soil, so rotating crops is one of the most effective strategies. Follow tomato plants with crops that don’t have the same pest problems. So, that means don’t plant anything in the same family.

2. Use Beneficial Nematodes

It might seem crazy to release more nematodes to fight the bad ones, but it’s an effective strategy. Remember, eliminating all of the nematodes in your soil is hard, if not impossible. Releasing resistant varieties marked with an N. is a safe choice.

Doing this doesn’t kill the harmful nematodes, but it does reduce their effects and keep the population under control. 

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Spider Mites

Dealing with spider mites is tricky because they’re hard to see. Even if you can’t see the spider mites, the damage is evident to everyone. Mites crawl around your plants, piercing leaves and sucking out the juices. 

Spider mites are most common in cooler temperate climates if the plants are in a greenhouse and found in outdoor, dryer regions. Mites live in colonies; you won’t find a single mite. 

How to Identify Spider Mites

Spider mites are microscopic; you need a 10x hand lens to examine them. You’ll notice the damage to your plants before the pests themselves. 

If you could see them, spider mites are oval-shaped and pale green. As they mature, they develop with dark green spots. 

Signs of a Spider Mite Infestation

An infestation of spider mites starts with little holes on the leaves as they chew and suck on the juices. Over time, as the infestation worsens, expect the leaves to develop a stippled and bronzed look, damaging the entire leaves’ structures. 

Other signs include:

• Yellowing leaves
• Dropping leaves
• Webs formed under the leaves 

How to Get Rid of Spider Mites

What do you do once you have spider mites eating your tomato plants? Gardeners have a few organic options. 

1. Neem Oil

The most effective way to get rid of spider mites is neem oil spray. Any garden center sells neem oil for gardens in a spray form. All you have to do is spray your plants; it might take more than one application to get rid of a large infestation. 

2. Insecticidal Soap 

Another option is to use insecticidal soap. It’s a safe option for plants. 

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Whiteflies

If you see tiny white, flying insects in your garden, chances are you have whiteflies. Whiteflies feed on the juices of your plant, leaving behind a sticky residue called honeydew. The problem with honeydew is that it’s a magnet for sooty mold. 

Whiteflies prefer to feed on new growth, so always check the new leaves first. Check the underside of leaves around the veins for these insects and feel for a sticky substance. 

Identifying Whiteflies

Despite their name, whiteflies aren’t an actual type of fly, but they do have wings and fly. Here’s what they look like.

• Small, measuring 1/12 of an inch
• Triangular in shape
• White

Signs of a Whitefly Infestation

The easiest sign of an infestation is to shake a few leaves or the plants simply. If a cloud of white insects flies out, you know that you have a problem. Aside from their appearance and honeydew on the leaves, there are other signs of whiteflies’ damage.

• Ants are attracted to the honeydew.
• Weakened plants
• Unable to perform photosynthesis
• Wilting leaves
• Yellowing leaves
• Stunted Growth
• Dropping leaves 

Getting Rid of Whiteflies in Your Garden

It’s tempting to reach for insecticides, but don’t even try. Whiteflies are resistant to most on the market, and there are other solutions. 

1. Try a Horticultural Oil

One of the first solutions that you can try is horticultural oil. These oils smother all stages of the whiteflies, killing them off effectively. 

2. Buy Sticky Traps

As you use an oil, place sticky traps around your garden. These traps catch the adult whiteflies and give you a way to monitor the population in your garden. 

3. Release Natural Predators

If the infestation seems to get worse, releasing natural predators in your garden can take care of the problem. Ladybugs, lacewings, and whitefly parasites are natural predators.

4. Use Insecticidal Soaps

Insecticidal soaps or botanical insecticides handle bad infestations. These will bring down the population to a manageable level. At that point, introducing predators should work. 

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Stink Bugs

Stink bugs are best known for being stinky and annoying. Not everyone associates them with tomato plants, but these little pests will suck the sap from your plants with their needle-like mouthparts. They also carry viruses that infect your plants. 

Identifying Stink Bugs

Most people identify stink bugs without much help. These insects are visible to the naked eye. Depending on their age, they can be colored yellow, red, tan, or brown. They have eight legs and antennae the length of their legs. 

Signs of a Stink Bug Infestation

It’s possible that you won’t see the stink bugs living in your garden, you will notice the damage to your ripening fruits. Here are signs of a stink bug problem in your garden.

• Yellow, uneven spots on the ripening tomatoes
• White sections inside of the fruit under the yellow spots
• A strong odor 

How to Get Rid of Stink Bugs in Your Garden

Squashing stink bugs is a no-go unless you enjoy the nasty scent they release. Instead, the safest and easiest way to control stink bugs is to trap them. 

1. Remove by Hand

Pick the stink bugs off by hand and drop them in a bucket of hot, soapy water. 

2. Encourage Natural Predators

Encourage their natural predators to visit your garden, such as birds and spiders. These predators help to keep their numbers in a controllable amount. 

Prevention is Key

All gardeners need to understand how to prevent pests; that’s key to organic gardening. If you practice prevention, facing pests will rarely take place. If pests invade your garden, chances are it’s one of these ten most common tomato plant pests. Don’t let tomato pests take you down; use these organic control methods to beat them back. 

Learn more about tomato pests

https://hgic.clemson.edu/factsheet/tomato-insect-pests/

https://extension.umd.edu/learn/insect-pests-tomato