What’s Eating My Tomatoes?

Why are your tomatoes covered in holes, cracks, or rotten lesions? Something must be eating them, and finding the culprit pest is the first step to fixing the problem.

But what are pests anyway? The term “pest” is a human definition for any insect we don’t want on our plants. This means pests are often native insect species that rely on our crops to survive. 

With these moral implications, I always think twice before spraying chemicals within gardens. They have unforeseen impacts on predatory bugs, pollinators, and soil health. Learn organic cultural control methods, and you’ll never reach for a pesticide again.

So, what’s eating your tomatoes, and how do we banish them from your plants? Let’s find out!

The Short Answer

Many of these pests thrive in situations that are easily preventable. Row covers, strong blasts of water, and sanitary garden conditions discourage pests from establishing themselves. Use these methods alongside the following targeted attacks to save your precious tomatoes.

The Long Answer

Methods for combatting pests really depends on the particular bug. Each one has its unique life cycle—disrupt it, and you remove its ability to take over your plants. Follow along and learn how to remove each pest from your tomato plants.

Aphids

Aphids come in many different shapes and sizes but are typically less than an eighth of an inch big with soft, squishy bodies. There are green, black, and multicolored types. These tiny insects generally attack leaves and stems; they sometimes feed on flowers and tomatoes. 

You’ll notice aphid damage when you see mottled leaves and giant clusters of aphids. They like to stick together, as they’re stronger in bigger populations. You also might notice ants around aphid clusters; ants farm aphids to eat their sweet, honey-like secretions. Ants spread aphids to new plants, making aphid farms.

Although they may seem serious, aphids rarely decimate crops. Natural predators like ladybugs, pirate bugs, and parasitic wasps often step in to eat aphids before they spiral out of control. In particularly severe infestations, use strong streams of water to knock them off your plant. Repeat daily for one or two weeks. This action removes aphids without any pesticides or damage to your garden ecosystem. 

Beetles

Beetles and their larvae eat tomato foliage, causing your plants to decline in vigor. Less vigorous plants mean fewer tomatoes come harvest time. Blister beetles are orange, black, and longer than they are wide. Avoid touching them with your bare hands, as they emit a blistering chemical! Use gloves instead.

Colorado potato beetles have black and yellow stripes and a small, round body. Flea beetles have the same shape as blister beetles, but they’re all black and shiny. Finally, tortoise beetles are distinct—look for round, brown, turtle-shaped beetles that resemble scales.

Avoid attracting these beetles in the first place with floating row covers or mesh insect netting. Place them over your plants in early spring, and remove them by summer so pollinators can reach tomato flowers.

If an infestation is already occurring, avoid spraying pesticides. Native birds eat these beetles, and pesticides interfere with the birds’ life cycles. Cut off any foliage with beetle larvae or eggs. Decompose them away from the garden to avoid future infestations.

Basil and nasturtiums are great tomato companions to ward off adult beetles with strong scents, so try planting them amid your crops next season. Ladybugs also feed on their larvae.

Hornworms

Hornworms grow giant! They sometimes reach four inches long, with thick, green, fleshy bodies. These voracious worms look like big, green caterpillars partially because of their diet—they quickly consume leaves and stems, decimating plants in a few days. Weak, leafless tomatoes struggle to set flowers and fruits, leaving you tomato-less! 

Hornworms earn their name from the horn that grows off their backside; it is usually red, although it can also be green. Adult hornworm moths lay eggs on tomato plants that hatch into these critters. 

These worms are native to North America, meaning they’re a part of a healthy ecosystem. A few aren’t bad, as bird and insect predators usually keep their populations in check. Hornworms are big problems in areas where growers spray pesticides or herbicides often. 

So, avoid spraying pesticides and go organic. The best way to control hornworms is to pick them off your plant. Relocate them to wild nightshades, or trap crop with other solanaceous plants. Put dead hornworms in a bucket for birds to eat, or squish and compost them. Look closely for them, as they camouflage well in tomato plants.

Melon Flies

Melon flies aren’t widespread in the United States except for in Hawaii. They’re warm climate lovers originating in Asia, but they’ve since spread globally. Adult flies are the size of a house fly with orange, brown, and yellow markings. Adults lay eggs underneath tomato fruits’ skin—eggs hatch into wormy larvae that tunnel into tomatoes.

Like pepper weevils, melon flies ruin entire crops come harvest time. The wormy larvae leave decay wherever they go, causing tomato fruits to rot prematurely. To target the larvae, we must first target the adult flies.

Use sticky traps to monitor for melon flies in Hawaii. Row or mesh covers eliminate this pest, as the flies can’t go through the netting to tomato fruits. Organic pheromone traps also work, as they lure male flies away from female ones, trapping them in the process.

Slugs and Snails

Slugs and snails are common throughout North American gardens, especially wet ones. Their mucousy bodies need moist, cool conditions to survive, so you’ll find them active at dawn and dusk. They hide underneath rocks, soil, and wood during the day. 

Many different snails and slugs thrive throughout the continent, ranging from long and thick to small and squat. Some have colorings and patterns, like the famous yellow and black banana slug from California. Others are all one color, like black or brown. Slugs are shell-less, while snails live inside their protective shells. Both of them feed voraciously on tomatoes in the right conditions.

A few slugs or snails are beneficial in your garden; they attract birds, small mammals, toads, and other predatory slugs. These species eat the pests for you, so you can focus on growing more tomatoes. If you’re dealing with too many slugs, try using beer bait! Fill a container with a light beer, bury it in your garden beds, and wait for slugs to creep in. They drown upon entering, and predators eat them out of the pitchers. 

If you have small tomato seedlings, protect them with a strip of copper around their stems. Copper zaps slugs and tricks them into slithering away from your tender seedlings.

Spider Mites

Spider mites are tiny little critters—they’re like miniature spiders. It is easy to notice their small red bodies and tangles of webs. They create homes on your tomatoes using their webs. Damaged leaves have many yellow spots and plenty of spiderwebs; the leaves eventually brown before falling off.

Spider mites thrive in dry, warm conditions. They often cover tomato plants during summertime, when rain is low and temperatures are high. The good news is they’re easy to remove! Since they like warm dryness, spraying them daily with cold water effectively knocks them off your plants. Spider mites enjoy a range of host plants, so watch your other ornamentals for them. They spread easily using their webs—a diligent eye and a strong hose keep them away.

Keep spider mites away by providing proper care to your tomato plants. Water-stressed tomatoes are more susceptible to pest damage than healthy ones. Adding a layer of compost or mulch near your plants helps water stay in the soil longer, so your plants can drink better!

Stink Bugs

Stink bugs are interesting little critters. Some are beneficial species, like the Florida predatory stink bug. This one eats other stink bugs! The main pest to look out for is the brown marmorated stink bug. This invasive species from Asia has quickly spread throughout the eastern U.S. It is also in some parts of the West Coast, although it is less frequent there. 

Brown marmorated stink bugs have brown backs with white spots throughout. Other types of stink bugs are orange, green, red, or black. They all have a similar shape—look for a small triangle-shaped head, two antennas, and a shield-shaped body with six legs. Their eggs hatch in groups before feeding on leaves, tomatoes, and stems.

The best way to keep this pest away is to prevent it from overwintering. Stink bugs like to hide in our homes throughout winter. Seal all entrances, including rooves, walls, and underhouse access points. Remove egg masses as you see them, and hand-pick any adults through the growing season. 

Thrips

Thrips are one of the tiniest pests around! You’ll see them as little green specks jumping from plant to plant. I’ve dealt with indoor and greenhouse thrip infestations, which are particularly severe compared to outdoor ones. Thrips love greenhouse conditions, where they thrive with warmth, humidity, and plenty of juicy plants to eat. 

Thrips are touchy—shake your plant, and you’ll notice them jumping around. They target leaves, flowers, and the occasional tomato fruit. Adult thrips lay eggs inside leaves, where babies have protection until they hatch. Some spread viral diseases that cause bronzing on the leaves of tomato plants.

Because thrips fly away when disturbed, you can use this to your advantage. Hose down plants with water daily, or twice daily for severe infestations. Do this for one to two weeks until you notice less thrips. Invite predatory bugs that eat thrips by planting plenty of wildflowers around or in your vegetable garden. A diverse garden is a resilient one! 

Tomato Fruit Worms

Similar to pepper weevils, tomato fruit worms are larvae of a moth. They tunnel into ripening tomatoes. Tomato fruit worms also have the name corn earworm, as they target corn, tomatoes, peppers, and a whole range of crops. After they feed, they drop into the soil below to pupate before emerging in spring as adult moths. Halt their life cycle, and you keep these worms from establishing themselves.

Prevent tomato fruit worm establishment by removing rotting, diseased, or ripe tomatoes from your garden. Pick tomatoes at the breaker stage to ripen them fully indoors. This prevents this pest from destroying ripening fruit before you can eat it. Once worms enter the tomatoes, they are effectively immune to organic treatments. 

If your tomatoes got hit badly this year, try crop rotation next season. Plant your tomatoes in a new area of your garden. Put herbs, annuals, or wildflowers where your tomatoes were. After two to three years, rotate again to keep these pests at bay.

Whiteflies

Like thrips, whiteflies fly around when you disturb their host plants. You’ll notice specks of white after touching your tomatoes—they fly around for a bit before settling back on your tomato plants. The good news is there are plenty of predatory bugs that feed on whiteflies, like ladybugs, lacewings, and predatory wasps. 

Similar to thrips, whiteflies thrive in greenhouse conditions. They appreciate warm, dry conditions with plenty of leafy plant material. They feed on tomato leaves, leaving white, fuzzy residue wherever they go. Keep them away from your plants with moist, cool cultural conditions. Water regularly to keep your tomatoes strong against this pest.

If infestations are severe, neem oil works well on this pest. It is an organic oil that coats tomato leaves, making it difficult for whiteflies to eat. Apply this oil in the morning or night to prevent accidental damage to pollinators. Neem oil doesn’t discriminate, hurting any living creature that eats it. Use this oil only if all other methods fail to control this pest.