Bugs That Eat Tomato Plants

If you grow tomatoes, you’ve likely faced the frustration of chewed leaves and damaged fruit. Dealing with bugs that eat tomato plants is a common challenge that can test any gardener’s patience.

These pests can appear quickly, turning a healthy plant into a struggling one in just days. But don’t worry. With the right knowledge, you can identify the culprits and take effective action. This guide will walk you through the most common offenders and give you clear, practical solutions to protect your crop.

Knowing exactly which insect is causing the problem is the first step to control. Here are the most frequent invaders you’ll encounter in your tomato patch.

1. Tomato Hornworms

These are perhaps the most notorious pests. Large, green, and camouflaged, they can strip a plant of its leaves overnight.

Identification: Bright green caterpillars with white V-shaped marks and a black “horn” on their rear. They grow up to 4 inches long.
Damage: They consume large portions of leaves and stems, and will also chew on green fruit.
Control: Hand-pick them off plants (drop them in soapy water). Encourage natural predators like braconid wasps, which lay eggs on the hornworms.

2. Aphids

Tiny and soft-bodied, aphids cluster on new growth and the undersides of leaves, sucking plant sap.

Identification: Small, pear-shaped insects in green, black, red, or peach colors. They leave behind a sticky residue called honeydew.
Damage: Curling, yellowing leaves and stunted growth. Honeydew can lead to sooty mold fungus.
Control: A strong blast of water from a hose knocks them off. Use insecticidal soap or neem oil sprays. Ladybugs are excellent natural predators.

3. Whiteflies

These tiny, moth-like flies swarm when the plant is disturbed and are common in warm climates or greenhouses.

Identification: Small, white, winged insects that flutter up from the undersides of leaves.
Damage: Sucking sap, causing yellowing, wilting, and stunting. They also produce honeydew.
Control: Yellow sticky traps can catch adults. Insecticidal soaps and horticultural oils are effective against the nymphs. Remove heavily infested leaves.

4. Flea Beetles

These tiny beetles get their name from their jumping habit when disturbed, similar to fleas.

Identification: Very small (1/16 inch), dark-colored beetles that leave behind numerous small, round holes in leaves, often called “shot-hole” damage.
Damage: Mostly cosmetic on established plants, but severe infestations on seedlings can weaken or kill them.
Control: Use floating row covers to protect young plants. Diatomaceous earth sprinkled around plants can help. Sticky traps are also useful.

5. Cutworms

These caterpillars hide in the soil during the day and emerge at night to feed, often severing young plants at the base.

Identification: Fat, gray or dull brown caterpillars up to 2 inches long, usually curled up when disturbed.
Damage: They chew through stems of young tomato transplants at soil level, causing plants to topple over.
Control: Place collars around transplants (use cardboard tubes or aluminum foil). Till soil in fall and spring to expose larvae. Hand-pick at night with a flashlight.

6. Spider Mites

These are not insects but arachnids, and they thrive in hot, dry, dusty conditions.

Identification: Extremely tiny, appearing as moving dots. Look for fine, silky webbing on the undersides of leaves. Leaves develop a stippled, bronze look.
Damage: They pierce plant cells to feed, leading to yellowed, dry leaves that may drop off.
Control: Increase humidity with regular overhead watering. Spray plants thoroughly with a strong jet of water. Apply insecticidal soap or neem oil, making sure to cover leaf undersides.

7. Colorado Potato Beetle

While they prefer potatoes, they will happily feast on tomatoes and other nightshades.

Identification: Adults are rounded, yellow-orange beetles with black stripes. Larvae are reddish-pink with black spots.
Damage: Both adults and larvae consume leaves, leading to significant defoliation.
Control: Hand-pick adults, larvae, and orange egg masses from leaves. Row covers can provide a barrier. Spinosad is an effective organic pesticide option.

8. Stink Bugs and Leaf-Footed Bugs

These shield-shaped bugs use piercing mouthparts to feed on developing fruit.

Identification: Stink bugs are shield-shaped in various colors. Leaf-footed bugs are brown or gray with a flat, leaf-like expansion on their hind legs.
Damage: They inject enzymes into fruit, causing cloudy blotches, yellow spots, and hard, white tissue underneath the skin.
Control: Hand-pick adults and nymphs (knock into soapy water). Remove nearby weed hosts. Use row covers before fruit sets.

Integrated Pest Management (IPM) for Your Tomatoes

IPM is a smart, sustainable approach that combines multiple strategies. The goal is manage pests, not necessarily to eradicate every single bug, with minimal environmental impact.

Step 1: Prevention is Key

Start with a strong, healthy garden ecosystem to avoid problems before they begin.

Choose Resistant Varieties: Select tomato varieties labeled with disease and pest resistance (look for codes like VFN on plant tags).
Practice Crop Rotation: Avoid planting tomatoes or other nightshades (peppers, eggplant, potatoes) in the same spot year after year. A 3-4 year rotation is ideal.
Encourage Beneficial Insects: Plant flowers like marigolds, calendula, dill, and yarrow to attract ladybugs, lacewings, and parasitic wasps that prey on pests.
Keep it Clean: Remove plant debris at the end of the season to eliminate overwintering sites for insects and disease.

Step 2: Regular Monitoring

Check your plants frequently, at least twice a week. Look under leaves, along stems, and at the base of plants. Early detection makes control much easier and prevents a small problem from becoming an infestation.

Step 3: Physical and Mechanical Controls

These methods involve physically removing or blocking pests.

Hand-Picking: Very effective for large pests like hornworms and potato beetles.
Traps: Yellow sticky traps for whiteflies and aphids; pheromone traps for specific moths.
Barriers: Floating row covers placed over young plants exclude many pests. Remember to remove them when plants flower to allow for pollination.
Water Spray: A strong jet of water dislodges aphids, spider mites, and whitefly nymphs.

Step 4: Organic and Biological Controls

When other steps aren’t enough, these options target pests while sparing beneficial insects.

Insecticidal Soap: Kills soft-bodied insects on contact but has no residual effect. Must coat the pest directly.
Neem Oil: A botanical oil that disrupts insect feeding and acts as a repellent. It’s also fungicidal.
Bacillus thuringiensis (Bt): A natural bacteria that is toxic to caterpillars (like hornworms) when ingested. Harmless to other insects, pets, and people.
Diatomaceous Earth (DE): A fine powder made from fossilized algae. It damages the exoskeletons of crawling insects. Reapply after rain.
Beneficial Nematodes: Microscopic worms applied to soil to control cutworms and other soil-dwelling larvae.

Step 5: Chemical Controls as a Last Resort

Synthetic pesticides should be used only if absolutely necessary. They can harm pollinators and beneficial insects, leading to worse pest outbreaks later. If you must use them, always choose the least toxic option, follow the label instructions exactly, and never apply during bloom when bees are active.

Creating a Resilient Tomato Garden

Beyond pest-specific tactics, overall plant health is your best defense. Stressed plants are more suseptible to insect attacks.

Water Consistently: Water deeply at the base of the plant to keep soil evenly moist. Avoid overhead watering which can promote disease.
Feed Appropriately: Use a balanced, slow-release fertilizer. Too much nitrogen can promote lush, tender growth that attracts aphids.
Provide Support and Airflow: Stake or cage your tomatoes to keep foliage off the ground. Good air circulation helps prevent fungal diseases and makes pests easier to spot.
Mulch: A layer of straw or shredded leaves conserves moisture, suppresses weeds, and can create a barrier for some soil pests.

FAQ: Common Questions About Tomato Pests

What are the little bugs on my tomato plants?
They are likely aphids or spider mites. Check the undersides of leaves. Aphids are usually clustered together, while spider mites leave fine webbing.

What is eating holes in my tomato plant leaves?
Large, irregular holes point to hornworms or slugs. Many small, round “shot” holes are classic signs of flea beetle feeding.

How do I keep bugs off my tomato plants naturally?
Focus on prevention: encourage beneficial insects, use row covers, plant companion flowers, and inspect plants regularly to hand-pick pests. Natural sprays like neem oil and insecticidal soap are effective follow-ups.

Why are there bugs on my tomato plants?
Bugs are a natural part of the garden ecosystem. Your tomato plants are a food source. The goal isn’t a bug-free garden, but a balanced one where pest numbers are kept low enough to prevent serious damage.

Should I use soapy water on my tomato plants?
A mild soap and water spray (1-2 teaspoons of mild liquid soap per gallon of water) can help with soft-bodied insects. Test it on a few leaves first to ensure it doesn’t cause damage, and avoid using in hot, sunny weather.

Dealing with pests is an ongoing part of gardening, but it doesn’t have to mean losing your harvest. By learning to identify the common bugs that eat tomato plants and using a layered IPM strategy, you can protect your tomatoes effectively. Remember, a healthy garden is a balanced one, where a few pests are managed by their natural predators. Stay observant, act early, and you’ll be well on your way to enjoying a bountiful, beautiful tomato crop season after season.