What Is Eating My Tomato Plant Stems

If you’ve found holes, notches, or entire sections missing from your tomato plant stems, you’re likely dealing with a hungry garden pest. Figuring out what is eating my tomato plant stems is the first step to saving your crop.

This damage can weaken or even kill your plants, but don’t worry. Many common culprits leave telltale signs. With a little detective work, you can identify the pest and choose the right solution.

Stem damage on tomatoes typically comes from insects or animals. The type of injury—whether it’s clean cuts, ragged holes, or bored tunnels—points to specific pests. Let’s look at the most common offenders and the evidence they leave behind.

Common Insect Pests and Their Signs

Insects are the most frequent cause of stem damage. They often feed at night or hide during the day, so you’ll need to inspect your plants carefully.

1. Tomato Hornworms

These are large, green caterpillars that can strip a plant fast. They blend in perfectly with stems and leaves.

Signs: Severe defoliation (missing leaves) and large, dark green droppings on leaves. You may find deep, ragged gouges taken out of stems, especially near the top of the plant.
Look for: The caterpillar itself, which can be up to 4 inches long.

2. Cutworms

These pests are notorious for severing young seedlings at the soil line. They hide in the soil during the day.

Signs: A healthy young tomato plant that is suddenly cut off at the base and lying on the ground. The cut is usually clean, like it was sliced with scissors.
Look for: Gray or brown caterpillars curled up in the soil near the damaged plant.

3. Stem-Boring Insects (Tomato Fruitworm & Stalk Borer)

These insects tunnel into stems, causing internal damage that’s often fatal.

Signs: Wilting of individual branches while the rest of the plant looks okay. You’ll see a small, neat entry hole in the stem, often with sawdust-like frass around it.
Look for: It’s hard to see the larva inside, but the wilting branch and entry hole are clear clues.

4. Colorado Potato Beetle Larvae

While they prefer leaves, severe infestations can lead them to feed on tender stems.

Signs: Skeletonized leaves and scoring or notching on softer stems. The larvae are hump-backed and red with black spots.
Look for: Clusters of orange eggs on leaf undersides and the brightly colored larvae.

Common Animal Pests

Larger creatures can also be the problem. Their damage is often more dramatic and happens quickly.

1. Rabbits

Rabbits make clean, angled cuts on stems, similar to those made by pruning shears. They typically feed low to the ground.

Signs: Stems cleanly cut off at a 45-degree angle. Damage is usually within the first two feet of the ground.

2. Deer

Deer cause ragged tearing because they don’t have upper front teeth. They pull and rip plant material.

Signs: Ragged stem ends, missing large sections of the plant, and hoof prints in soft soil. Damage can occure at any height.

3. Voles

These small rodents gnaw on stems at the base, often under cover of mulch or grass.

Signs: Irregular gnaw marks near the soil line, sometimes girdling the stem completely. Look for small, mouse-like runways in the grass.

How to Diagnose the Problem: A Step-by-Step Guide

Follow these steps to identify your pest accurately.

Inspect the Damage Time: Check plants early in the morning or at dusk when many pests are active.
Examine the Type of Cut: Is it clean (rabbits, cutworms) or ragged (deer, hornworms)? Is the plant severed or just notched?
Look for the Pest: Check the undersides of leaves, along stems, and in the soil at the plant’s base. Bring a flashlight for night inspection.
Check for Droppings: Insect frass (like hornworm poop) or animal scat can provide big clues.
Look for Secondary Signs: Holes in the soil (voles), hoof prints (deer), or slime trails (slugs, though they rarely eat stems).

Effective Control and Prevention Methods

Once you know the culprit, you can choose a targeted response.

For Insect Pests:

Handpicking: For hornworms and potato beetles, simply pick them off and drop them into soapy water. It’s very effective.
Bacillus thuringiensis (Bt): This natural soil bacteria is a safe, organic spray that targets caterpillars like hornworms and cutworms.
Diatomaceous Earth: Sprinkle a ring of this powder around plant stems. Its sharp edges deter and dehydrate soft-bodied insects.
Row Covers: Use lightweight fabric covers to physically block insects from reaching young plants. Remember to remove them when flowers appear for pollination.
Crop Rotation: Avoid planting tomatoes in the same spot each year to disrupt pest life cycles.

For Animal Pests:

Fencing: This is the most reliable method. Use 2-foot high chicken wire buried a few inches for rabbits. For deer, you’ll need a fence at least 8 feet tall.
Collars for Seedlings: Place cardboard tubes or aluminum foil collars around young stems, pushing them an inch into the soil to stop cutworms.
Repellents: Commercial or homemade sprays (like egg and water mixtures) can deter rabbits and deer, but they need reapplication after rain.
Remove Habitat: Keep grass short and clear away brush piles to reduce hiding spots for voles and rabbits.

Healthy Plants Resist Pests Better

Strong, unstressed plants are less appealing to pests and can recover from minor damage. Ensure your tomatoes have:

Consistent watering (avoid overhead watering to prevent disease).
Proper spacing for good air circulation.
Balanced nutrition—too much nitrogen can create tender, pest-susceptible growth.
A layer of mulch to regulate soil moisture and temperature.

FAQ Section

What is chewing my tomato stems at night?
Nocturnal feeders include cutworms, hornworms (often feed at dusk/dawn), slugs/snails (on young stems), and animals like deer and rabbits.

What animal eats tomato plant stems?
Rabbits, deer, voles, groundhogs, and sometimes birds can cause stem damage. The type of cut (clean vs. ragged) helps identify which one.

How do I keep bugs from eating my tomato stems?
Use physical barriers like collars for seedlings, inspect plants regularly and handpick pests, encourage beneficial insects, and use organic sprays like Bt as a last resort.

Why are there holes in my tomato stems?
Small, neat holes are often from stem-boring insects like the tomato fruitworm. Larger, irregular holes or notches are from chewing pests like hornworms or beetles.

Can a tomato plant recover from stem damage?
Yes, if the damage isn’t complete girdling. You can often brace a damaged stem with a splint and tape. Plants with good roots will usually send out new growth.

Finding damage on your tomato plants can be frustrating, but quick identification is key. By looking closly at the evidence and using the right control methods, you can protect your plants and still enjoy a great harvest. Remember, a little vigilance in the garden goes a long way.