Identifying the specific culprit responsible for damaged tomato fruit is the first step toward implementing an effective and targeted pest management strategy. Damage to fruit and foliage can be caused by a wide range of animals, from large vertebrates to tiny invertebrates, each leaving distinct signs of their presence. Understanding the habits and dietary needs of these different garden invaders provides the necessary insight to safeguard the remaining harvest.
Primary Culprits: Mammals and Birds
Mammals and birds are common culprits that cause large, visible damage to tomato fruits, often targeting them for their high water content and sugars. Squirrels are frequently attracted to the juicy pulp, especially during dry summer months when hydration sources are scarce. They are active during the day and may take just a single bite out of multiple tomatoes, ruining several fruits in a short period.
Larger nocturnal mammals like raccoons and opossums are also responsible for significant losses, as they are drawn to the sweet, ripe fruit. Raccoons, with their manipulative paws, may remove entire fruits or leave behind messy, half-eaten remains scattered on the ground. Deer will consume entire tomatoes and can also cause extensive trampling damage to the plant structure itself.
Birds, such as mockingbirds, crows, and starlings, are known to peck at ripening tomatoes, causing small but numerous holes in the skin. This behavior is motivated by their search for moisture, similar to squirrels, and they are attracted to the bright red color of the ripe fruit. A single peck can be enough to introduce pathogens, leading to rot and rendering the tomato unusable.
Microscopic Marauders: Insects and Invertebrates
While large animals cause immediate, obvious fruit damage, smaller invertebrates cause harm through defoliation and tunneling into the fruit. The tomato hornworm is one of the most recognizable insect pests, growing into a large, thumb-sized caterpillar that feeds voraciously on the foliage and fruit. This larva can defoliate an entire tomato plant in just a few days due to its rapid growth and appetite.
Slugs and snails are mollusks often active at night, thriving in cool, moist conditions. They attack the fruit and leaves, leaving behind characteristic ragged holes in the foliage and on the surface of the tomatoes. Their presence is often betrayed by the silvery, dried mucus trails they leave behind as they move across the plant and soil.
Another common pest is the cutworm, the larval stage of various night-flying moths, which causes damage to young tomato transplants. These caterpillars typically sever the stem of a seedling at the soil line, causing the young plant to fall over. Once disturbed, cutworms characteristically curl up into a C-shape, making them identifiable when digging near a freshly damaged plant.
Identifying the Attacker By Damage Pattern
Determining the specific animal responsible for the damage is possible by analyzing the distinct patterns of feeding and evidence left behind. Mammals with sharp teeth, like squirrels and rats, often leave medium to large holes with relatively clean, sharp edges on the fruit. They may take only a single bite before moving to a new tomato, maximizing the number of ruined fruits.
In contrast, raccoons or opossums, which possess less precise dental structures, tend to leave behind messy, torn fruit with ragged edges or may simply remove the entire tomato from the vine. The presence of droppings and visible footprints near the plants confirms a mammalian culprit, with larger prints suggesting a raccoon or deer. Birds create small, shallow, often repeated pecks on the fruit surface, which may be confined to the upper side of the tomato while it is still on the vine.
Damage from invertebrates is usually more structural or internal. Slugs and snails leave behind their tell-tale silvery slime trails, which are particularly visible on the soil or mulch around the plant. Hornworms leave large, dark green, pellet-like droppings, known as frass, on the leaves below where they are feeding. Their damage is characterized by completely defoliated stems and raggedly chewed fruits.
Implementing Targeted Garden Defenses
Once the specific animal is identified, defense strategies can be tailored to the pest’s size and behavior. For larger vertebrates such as deer and raccoons, physical barriers are the most reliable defense. This requires sturdy fencing that is at least six to eight feet tall for deer, or a structure secured at the base to deter climbing and digging mammals. Netting draped over the tomato cages or plants can also be effective at preventing daytime attacks from birds and squirrels.
Preventative measures for invertebrates focus on cultural practices and direct removal. Tomato hornworms should be controlled by vigilant hand-picking, especially after spotting their large droppings, or by using biological controls like Bacillus thuringiensis (Bt), a naturally occurring soil bacterium that is toxic to caterpillars. Slugs and snails can be managed with iron phosphate baits, which are safer for pets and wildlife, or by setting up simple beer traps sunk into the soil.
Reducing the attractant is a general strategy for all types of predation. Providing a separate water source away from the garden can deter thirsty mammals and birds from pecking tomatoes. Topical repellents, such as those based on chili pepper extracts, can also be applied directly to the fruit to deter animals with a sensitive sense of taste, though the fruit must be thoroughly washed before consumption.