Tomatoes are one of the most popular garden vegetables worldwide, yet they are vulnerable to insects and animals that can compromise a harvest. The plant’s structure, from roots to fruit, offers a food source for numerous pests, each leaving distinct signs of their presence. Protecting a tomato crop hinges on correctly identifying the culprit. Understanding the specific feeding patterns allows for a targeted and effective response.
Pests Causing Damage to Tomato Leaves and Stems
The foliage of the tomato plant is often the initial target, and the nature of the leaf damage provides clear evidence of the pest at work. The Tomato Hornworm is a large larva that can rapidly defoliate entire sections of the plant. The most telling sign is the presence of large, black, pellet-like droppings, known as frass, which accumulate below the feeding site, often accompanying massive leaf loss.
Smaller insects leave behind damage that appears less like chewing and more like tiny perforations. Flea beetles are tiny, jumping insects that chew numerous small, round holes across the leaves, creating “shot-hole” damage. This feeding is particularly harmful to young seedlings, which may not have enough leaf surface area to survive the assault.
Other pests drain the plant’s internal fluids rather than consuming leaf tissue. Aphids and whiteflies use piercing-sucking mouthparts to extract sap from the leaves, causing the foliage to yellow, curl, and wilt prematurely. These sap-suckers excrete a sugary waste product called honeydew, which leaves the leaves feeling sticky and promotes the growth of black sooty mold. Disturbing the plant causes a small cloud of tiny, white insects to fly up from the undersides of the leaves.
Pests Directly Attacking Tomato Fruit
Damage to the fruit itself is the most frustrating, as it directly impacts the final harvest. Stink bugs and leaffooted bugs are piercing-sucking insects that insert their mouthparts into the fruit to feed on the internal juices. This action causes localized cell collapse, resulting in internal white, corky, or spongy tissue just beneath the skin, visible externally as “cloudy spots.”
In contrast, the Tomato Fruitworm is a caterpillar borer that creates a distinct point of entry, often near the stem end of the fruit. Once inside, the larva tunnels, creating a messy, watery cavity filled with its waste. A single larva may emerge from one fruit to bore into another, causing multiple points of damage and premature ripening.
Ground-level pests like slugs and snails are attracted to the fruit, particularly those resting on the soil. These mollusks scrape away at the fruit surface, leaving large, irregular holes with smooth edges. The definitive sign of their presence is the silvery, dried mucus or slime trail left on the fruit or surrounding surfaces. Larger vertebrate pests, such as birds or rodents, consume large, messy portions of the fruit. Birds typically peck at the fruit, creating smaller, targeted holes, while rodents tend to gnaw and consume larger sections.
Pests Affecting the Plant Base and Roots
Damage occurring at or below the soil line is often difficult to diagnose, leading to the sudden collapse or gradual decline of the plant. Cutworms are moth larvae that live in the soil and feed on young tomato transplants at night. They chew through the stem right at the soil line, causing the seedling to be cleanly severed and fall over.
Another threat to the plant’s foundation comes from microscopic roundworms called nematodes. Root-knot nematodes enter the roots and stimulate the plant tissues to swell, forming distinctive galls or knots. These galls interfere with the root system’s ability to absorb water and nutrients, leading to above-ground symptoms such as stunted growth, yellowing of the leaves, and wilting, especially in hot weather. The root damage is only confirmed by digging up the plant and observing the swollen, knotty roots.