10 Common Tomato Plant Pests and How to Fight Them Organically

By Bethany Hayes (revised and updated)

The 30-second version: Most tomato pests are manageable organically if you catch them early. The single most effective thing you can do is walk your garden often and look closely — especially under the leaves. Hand-pick what you can, encourage beneficial insects, use row covers on young plants, and reach for sprays only when a problem is genuinely getting away from you. And remember: not every bug on your tomato is an enemy.

Tomatoes are the plant almost every gardener wants to grow — and pests love them just as much as we do. A bad infestation can chew through foliage, ruin fruit, and in some cases kill plants outright. Learning to manage these pests organically, without reaching for harsh chemicals, is one of the most useful skills a tomato grower can build.

Before you spray anything, take a moment to identify what you are actually looking at. Many of the insects in your garden are harmless, and some are actively helping you by eating the pests that cause damage. Knocking out the good bugs along with the bad ones usually makes pest problems worse, not better.

Start here: organic basics that work on almost any pest

Before we get into specific pests, these habits prevent or shut down the majority of tomato pest problems. They show up again and again in the sections below, so it is worth doing them by default:

• Scout often. Check your plants a couple of times a week, and always look at the undersides of leaves and the newest growth, where most pests hide and lay eggs.
• Hand-pick. For larger pests like hornworms, beetles, and stink bugs, dropping them into a bucket of soapy water is fast, free, and very effective in a home garden.
• Encourage beneficial insects. Ladybugs, lacewings, and tiny parasitic wasps eat or parasitize many tomato pests. Planting flowers nearby and avoiding broad-spectrum sprays keeps them around.
• Use row covers on young plants. Lightweight fabric covers keep beetles, flies, and egg-laying adults off seedlings. Remove them once plants flower so pollinators can reach the blooms.
• Rotate crops. Do not plant tomatoes (or their relatives — peppers, eggplant, potatoes) in the same spot year after year. Rotation breaks the life cycle of soil-borne pests.
• Clean up debris. Many pests overwinter in dead plant material and weeds. A tidy garden in fall means fewer pests in spring.

Know your good bugs

If you see these in your garden, leave them alone — they are working for you. Ladybugs and their alligator-shaped larvae devour aphids. Green lacewing larvae eat aphids, mites, and small caterpillars. Parasitic wasps (most are tiny and harmless to people) lay eggs in or on pests like hornworms and aphids. Predatory mites hunt down spider mites. A garden with a healthy population of these predators largely polices itself.

10 common tomato plant pests and how to get rid of them organically

The exact pests you face depend on where you garden, but these ten are among the most common and most damaging for tomato growers across North America.

1. Cutworms

Cutworms feed at night on seedlings and young plants. True to their name, they chew through stems right at or just above the soil line, often toppling a transplant overnight. The damage tends to be sudden and total — you come out in the morning to find a seedling cut off at the base.

How to identify cutworms

Despite the name, cutworms are not worms — they are the larvae (caterpillars) of several species of night-flying moths. They look like soft, smooth grubs, usually about an inch or two long, in shades of gray, brown, pink, green, or black, often with faint stripes. When disturbed, they curl into a tight “C” shape. Because they feed at night and hide in the soil during the day, you rarely see them in the act.

Signs of a cutworm problem

• Seedlings cut off cleanly at or near the soil line
• Wilted or toppled transplants
• Grubs that curl into a “C” when you dig in the soil near a damaged plant

How to control cutworms organically

• Use collars (the most reliable fix). Wrap a collar of cardboard, newspaper, or aluminum foil around each transplant’s stem. Make it one to two inches wide and push it about an inch into the soil so cutworms cannot reach the stem. Remove it once the plant is established.
• Hand-pick at night. Go out after dark with a flashlight and pick cutworms off the soil surface. This is genuinely effective in a small garden.
• Clear away debris. Cutworms overwinter in dead plant material and weeds, so a fall cleanup reduces next year’s population.
• Try beneficial nematodes. Certain commercially available beneficial nematodes attack soil-dwelling caterpillars and can lower cutworm numbers.

Skip the cornmeal. You will see advice online to sprinkle cornmeal around plants on the theory that cutworms eat it and die. There is no scientific support for this — it is a garden myth. Stick with collars, which actually work.

2. Aphids

Aphids are tiny soft-bodied insects that cluster densely on stems and new growth. A few aphids are nothing to worry about, but a heavy infestation can weaken or stunt a plant. They damage tomatoes in two ways: they suck sap (and can transmit plant viruses as they feed), and they excrete a sticky substance called honeydew that encourages sooty mold, a black coating that blocks light and interferes with photosynthesis.

How to identify aphids

• Very small, around one-tenth of an inch long
• Usually green or black, but also brown, reddish, or gray depending on species
• Two short tube-like projections (called cornicles) at the rear of the body — a key identifying feature
• Almost always found in clusters, rarely alone

Signs of an aphid problem

• A sticky, shiny coating (honeydew) on leaves
• Black sooty mold growing on the honeydew
• Ants traveling up and down the plant — they farm aphids for the honeydew
• Curled or distorted new growth

How to control aphids organically

• Blast them with water. A strong jet from the hose knocks aphids off the plant, and they mostly cannot find their way back. For small infestations this is often all you need.
• Pinch off heavily infested foliage and throw it in the trash — not the compost pile.
• Bring in beneficial insects. Ladybugs and lacewings are aphid-eating machines. Encouraging or releasing them handles larger outbreaks.
• Use insecticidal soap. Made from natural fats and plant oils, it kills aphids on contact while being gentle on the plant. Spray directly on the clusters, including leaf undersides.

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3. Tomato Hornworms

The hornworm is the most iconic tomato pest — big, dramatic, and capable of stripping a mature plant of its leaves in just a day or two. The good news is that, because they are so large, they are also one of the easiest pests to control once you spot them.

How to identify hornworms

Hornworms are large green caterpillars, two to four inches long, with a soft horn-like projection at the rear end and diagonal white markings along the body. They are the larvae of sphinx (hawk) moths. Their green color blends in so well with tomato foliage that they are surprisingly hard to see despite their size — often the chewed leaves and dark droppings give them away before you spot the caterpillar itself.

Signs of hornworms

• Large sections of foliage stripped or chewed, seemingly overnight
• Dark green or black droppings (frass) on leaves and on the ground below
• Occasional chewing on green fruit

How to control hornworms organically

• Hand-pick them. This is the simplest and most effective method. Drop them in soapy water. Tip: a small black-light flashlight makes hornworms glow at night, which makes them much easier to find.
• Let the parasitic wasps do the work. If you find a hornworm covered in small white rice-like cocoons, leave it in place. Those are the cocoons of a parasitic wasp that has already killed the hornworm from the inside; the emerging wasps will go on to attack more hornworms.
• Spray Bacillus thuringiensis if needed. Bacillus thuringiensis (often sold simply as a caterpillar control) is a naturally occurring soil bacterium — not a fungus — that, when eaten by caterpillars, stops them from feeding. The variety you want is Bacillus thuringiensis var. kurstaki. It is most effective on young caterpillars and is harmless to people, pets, bees, and earthworms. See the University of Minnesota Extension guide to tomato hornworms for details.

A note on marigolds: You will often hear that planting marigolds repels hornworms. There is little evidence for this, so do not rely on it as your main defense. (Marigolds do have a documented benefit against root-knot nematodes — more on that below.)

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4. Tomato Fruitworms (Corn Earworms)

The tomato fruitworm — the same insect known as the corn earworm and the cotton bollworm — is one of the most damaging tomato pests precisely because it attacks the fruit directly. It is far more common in most home gardens than blister beetles, which is why it earns a spot on this list. The caterpillar bores into developing tomatoes, leaving a watery, rotting cavity full of droppings, and a single worm can ruin several fruits as it moves from one to the next.

How to identify tomato fruitworms

The caterpillars grow up to about 1.5 inches long and vary in color from green to pink, brown, or nearly black, with light stripes running the length of the body. The adult is a tan to greenish-brown moth. Eggs are tiny, white, and laid singly on leaves near the fruit.

Signs of a tomato fruitworm problem

• Round entry holes near the stem end of fruit
• A watery, mushy internal cavity filled with droppings when you cut a fruit open
• Fruit that ripens and drops prematurely

How to control tomato fruitworms organically

• Scout for eggs and tiny caterpillars. Once a worm is inside the fruit, no spray can reach it, so the whole game is catching them early, while larvae are still on the surface.
• Spray Bacillus thuringiensis on young larvae. The kurstaki variety works well when caterpillars are small and still feeding on foliage and fruit surfaces.
• Encourage parasitic wasps. Tiny Trichogramma wasps parasitize fruitworm eggs and can provide real control.
• Pick and destroy infested fruit to stop the larvae from maturing and starting another generation.

For a thorough rundown, see UC Integrated Pest Management on the corn earworm / tomato fruitworm.

5. Colorado Potato Beetle

Colorado potato beetles love all members of the nightshade family. Potatoes are their first choice, but they readily move to tomatoes, eggplants, and peppers. They live in nearly every U.S. state (with a few exceptions including California, Nevada, Alaska, and Hawaii), and both the adults and the larvae are voracious leaf-eaters that can quickly defoliate a plant.

How to identify Colorado potato beetles

Adults are about the size of a dime with rounded backs and ten alternating yellow and black stripes — a clear giveaway. The females lay clusters of bright yellow-orange eggs on the undersides of leaves. The larvae are plump, reddish to pink, with rows of black spots along their sides. Check leaf undersides during the day to find both eggs and larvae.

Signs of a Colorado potato beetle problem

• Chewing damage that starts at the growing tips and spreads to whole leaves
• Leaves skeletonized down to the veins
• Stunted growth and reduced fruiting; severe infestations can kill young plants

How to control Colorado potato beetles organically

• Hand-pick adults, larvae, and egg clusters. In a home garden this is the single most effective control. Crush the egg clusters on the leaf undersides and drop adults and larvae into soapy water.
• Use row covers on young plants to keep overwintered adults from reaching them in spring.
• Rotate crops and mulch heavily. A thick straw mulch makes it harder for emerging adults to find your plants, and rotating away from where you grew nightshades last year disrupts their cycle.
• Spray only as a last resort. If you must, a product based on Bacillus thuringiensis var. tenebrionis (a strain specific to beetle larvae) or spinosad can help. Be aware that this beetle is famous for rapidly developing resistance to insecticides — it has developed resistance to dozens of active ingredients — so never rely on the same spray repeatedly. See Michigan State University Extension on resistance management.

6. Flea Beetles

Flea beetles are tiny but can do real damage, especially to young plants. The adults chew the leaves and foliage while the larvae feed on roots underground. They attack a wide range of garden plants — tomatoes, plus cabbage, corn, lettuce, potatoes, and peppers.

How to identify flea beetles

• Very small, shiny beetles that jump like fleas when disturbed
• Black, bronze, bluish, or brown, sometimes with stripes
• Enlarged hind legs built for jumping

Signs of a flea beetle problem

The telltale sign is a scattering of tiny round “shotgun” holes across the leaves. Established plants usually shrug off the damage, but seedlings can be seriously set back or killed.

How to control flea beetles organically

• Use row covers over seedlings in spring — this is the most effective prevention, and it also stops adults from laying eggs in the soil.
• Clear weeds and debris where adults overwinter.
• Set out sticky traps to capture the jumping adults and gauge how big the population is.
• Dust with diatomaceous earth. A light dusting on the leaves deters feeding. (See our guide to diatomaceous earth uses.)
• For heavy infestations, a botanical insecticide such as spinosad can knock the population down — apply at dusk to protect bees.

7. Root-Knot Nematodes

Nematodes are microscopic worms, and there are tens of thousands of species — most of them harmless or even beneficial. The one that causes trouble for tomatoes is the root-knot nematode. It attacks the roots, causing knobby swellings (galls) that block the plant’s ability to take up water and nutrients. The result is a plant that struggles no matter how well you water and feed it.

Signs of a root-knot nematode problem

Because they live underground and are invisible to the naked eye, you diagnose them by their effects:

• Stunted growth and wilting, even with adequate water
• Yellowing leaves
• Knobby galls or swellings on the roots when you pull up an affected plant (the clearest sign)

How to control root-knot nematodes organically

Once root-knot nematodes are established in the soil, eliminating them is very difficult, so the emphasis is on prevention and resistant plants:

• Plant resistant varieties. Look for tomato varieties labeled with an “N” for nematode resistance (often shown as “VFN,” meaning resistance to Verticillium wilt, Fusarium wilt, and Nematodes). These plants still get some root infection, but the nematodes cannot reproduce normally, so yields hold up. This is the most practical home-garden solution. See NC State Extension on controlling root-knot nematodes in the home garden.
• Rotate crops. Follow tomatoes with plants that are not in the same family and are not good nematode hosts. Rotation starves the nematode population over time.
• Plant French marigolds as a cover or rotation crop. French marigolds (Tagetes patula) release compounds from their roots that suppress root-knot nematode populations — this is the marigold benefit that actually has research behind it. To work, they generally need to be grown as a dense planting over a season, not just tucked in beside tomatoes.

A clarification: “Beneficial nematodes” sold for pest control target soil-dwelling insect larvae (like grubs and some caterpillars) — they do not control root-knot nematodes. Don’t confuse the two.

8. Spider Mites

Spider mites are tricky because they are almost too small to see — but the damage they cause is obvious. They are not insects at all; they are arachnids (eight legs, like spiders), and they have piercing-sucking mouthparts. They pierce leaf cells and suck out the contents, which produces a characteristic fine speckling rather than chewed holes. Spider mites thrive in hot, dry, dusty conditions, so they are most troublesome in the heat of summer and in dry spells.

How to identify spider mites

Individual mites are nearly microscopic — you may need a magnifying lens to see them clearly. Under magnification they appear as tiny oval, pale-green to reddish specks, often with two dark spots. You will usually notice the damage and the fine webbing before you ever see the mites themselves. Tap a suspect leaf over a sheet of white paper and look for moving dust-sized specks.

Signs of a spider mite problem

• Fine yellow or white stippling (speckling) on the leaves — not holes
• Leaves that turn bronzed or yellow and dry out as damage worsens
• Fine silky webbing on the undersides of leaves and between stems
• Leaf drop in heavy infestations

How to control spider mites organically

• Spray the plants with water. A forceful spray, especially on leaf undersides, knocks mites off and raises humidity, which they hate. Repeat every few days.
• Use insecticidal soap or horticultural oil. Both kill mites on contact; thorough coverage of the leaf undersides is essential, and you will likely need more than one application.
• Apply neem oil for larger infestations, again coating the undersides of leaves.
• Release predatory mites, which hunt and eat spider mites, for persistent problems.
• Avoid broad-spectrum insecticides, which kill the natural predators and often make mite outbreaks worse.

9. Whiteflies

If a little cloud of tiny white insects flies up when you brush against your tomato plant, you have whiteflies. They feed on plant sap and, like aphids, excrete sticky honeydew that invites sooty mold. They prefer tender new growth, so check the newest leaves and their undersides first.

How to identify whiteflies

• Tiny, about one-sixteenth of an inch long
• White, moth-like, with wings held roof-like over the body
• Found in groups on the undersides of leaves; they scatter into a white cloud when disturbed

Signs of a whitefly problem

• A cloud of white insects flying up when you shake the plant
• Sticky honeydew and black sooty mold on leaves
• Ants attracted to the honeydew
• Yellowing, wilting leaves and weakened, stunted plants in heavy infestations

How to control whiteflies organically

• Use yellow sticky traps to capture adults and monitor the population.
• Apply horticultural oil or insecticidal soap, which smother whiteflies at all life stages. Coat the leaf undersides and repeat as needed.
• Release natural predators. Ladybugs, lacewings, and tiny whitefly-parasitizing wasps all help bring numbers down.
• Skip the synthetic insecticides. Whiteflies have developed resistance to many of them, and the sprays kill the predators that would otherwise help you.

10. Stink Bugs

Stink bugs are best known for the unpleasant odor they release when disturbed, but they are also a genuine tomato pest. They pierce fruit with needle-like mouthparts to suck out sap, and some species can transmit plant diseases. The feeding damage shows up on the fruit rather than as obvious leaf damage.

How to identify stink bugs

Stink bugs are shield-shaped insects, easily visible to the naked eye, in shades of green, brown, tan, gray, yellow, or red depending on species and age. Like all insects, they have six legs (not eight) and a pair of antennae. The young (nymphs) are rounder and often more brightly colored than the adults.

Signs of a stink bug problem

• Yellow or whitish, slightly sunken spots (“cloudy spot”) on ripening fruit
• Hard, white, pithy areas just under the skin when you cut the fruit open
• The bugs themselves on plants, and their distinctive odor

How to control stink bugs organically

• Hand-pick them into a bucket of soapy water. Do not squash them on the plant unless you enjoy the smell.
• Keep weeds down, since weedy areas give stink bugs places to shelter and breed.
• Encourage natural predators such as birds, spiders, and parasitic insects.
• Use row covers on younger plants, removing them at flowering so pollinators can reach the blooms.

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Myths that don’t work

Plenty of popular “organic” pest tricks circulate online that simply don’t hold up. Save yourself the effort:

• Cornmeal to kill cutworms. The claim that cutworms eat cornmeal and die has no scientific support. Use stem collars instead.
• Marigolds to repel hornworms (and most flying pests by scent). The evidence isn’t there. Marigolds’ one research-backed benefit is that French marigolds suppress root-knot nematodes when grown as a dense crop — a soil effect, not an airborne repellent.
• Planting one or two companion plants as a pest force-field. Companion planting can help at the margins, but a couple of basil or marigold plants will not protect a tomato patch on their own. Treat it as one small tool, not a substitute for scouting and the basics.
• “Spray everything at the first bug.” Broad-spectrum sprays — even some organic ones — kill the beneficial insects that keep pests in check, which often leads to worse outbreaks later. Identify first, then choose the most targeted method.

Prevention is the real secret

The gardeners who rarely battle serious pest problems are usually the ones doing the unglamorous basics: scouting often, keeping the garden clean, rotating crops, protecting young plants, and letting beneficial insects do their job. Do those things, deal with problems while they are small, and you will rarely need anything stronger than a hose, your hands, and the occasional organic spray.

Common Questions

What’s the safest spray to use on tomato pests?
For soft-bodied pests (aphids, whiteflies, spider mites), insecticidal soap and horticultural oil are about as gentle as it gets. For caterpillars (hornworms, fruitworms), Bacillus thuringiensis var. kurstaki is very targeted and harmless to people, pets, and bees. Spinosad is effective on a wider range of pests but is toxic to bees when wet, so apply it at dusk after bees have stopped foraging.

What’s eating my tomato plants at night?
The usual nighttime culprits are cutworms (seedlings cut off at the base), hornworms (large sections of leaves stripped, with droppings below), and slugs (slime trails and ragged holes). A nighttime flashlight check will usually reveal which one you have.

Are these pests harmful to people?
Almost none of them are. The main exception is the blister beetle (not covered in detail here), which can cause skin blisters if crushed against the skin — wear gloves if you handle them. Stink bugs are merely smelly, and the rest are harmless to humans.

Does companion planting really stop pests?
It can help a little, but it is not a force-field. The strongest evidence is for French marigolds suppressing root-knot nematodes in the soil. For everything else, treat companion planting as a minor supporting tactic alongside scouting, row covers, and crop rotation.

Learn more from university extension sources

• Clemson Cooperative Extension — Tomato Insect Pests
• University of Maryland Extension — Insect Pests of Tomato
• University of Minnesota Extension — Tomato Hornworms
• UC Integrated Pest Management — Corn Earworm / Tomato Fruitworm
• Michigan State University Extension — Colorado Potato Beetle Resistance Management
• NC State Extension — Control of Root-Knot Nematodes in the Home Garden