When a gardener finds developing fruit partially consumed or removed, they must identify which creatures are responsible for damaging the unripe green tomatoes. The culprits range from small insects to larger mammals, each leaving distinct signs of their garden raid. Understanding the specific feeding habits and motivations of these pests is the first step toward protecting the remaining harvest.
Primary Mammalian Eaters
Mammalian garden raiders often target green tomatoes not for taste, but out of necessity, such as seeking hydration during dry periods. Raccoons are nocturnal visitors that typically leave behind messy, half-eaten tomatoes, often pulling the fruit from the vine and discarding the remnants nearby. Squirrels, which are active during the day, may remove an entire green tomato and carry it away, or they might take a single bite and abandon the fruit, leaving a clean-cut bite mark.
Groundhogs and deer also pose a threat, though their damage is often more extensive than just the fruit. Groundhogs are known for being particularly destructive, consuming large portions of the plant as well as the developing fruit, and their messiness often involves trampling the surrounding foliage. Deer, being tall browsers, will typically strip the upper parts of the plant of both leaves and fruit, leaving raggedly torn edges on the remaining stems and foliage. Smaller rodents like mice and rats tend to feed on fruit closest to the ground, creating gouged-out sections in the tomato with noticeable incisor marks.
Insect and Invertebrate Damage
Among the smaller pests, the tomato hornworm is perhaps the most notorious for its voracious appetite for unripe fruit. This large, green caterpillar, the larval stage of the sphinx moth, is highly camouflaged but leaves behind distinct evidence of its presence, including large, dark green or black droppings known as frass. A single hornworm can defoliate a significant portion of a tomato plant quickly, and while they primarily consume leaves, they will also chew large, shallow holes into the green fruit itself.
Invertebrates such as slugs and snails operate at night, damaging green tomatoes that rest on or near the soil surface. Their feeding leaves behind irregular holes with smooth edges, and the presence of a silvery, dried slime trail is the definitive marker of a slug or snail attack. These soft-bodied creatures do not remove the fruit from the plant but rather rasp away the surface material. Their damage is easily distinguishable from the cleaner cuts left by rodents.
Solanine: The Chemical Defense of Green Tomatoes
The green tomato’s natural defense against being eaten is a concentrated chemical compound called solanine, a glycoalkaloid found throughout the nightshade family of plants. Solanine acts as a natural deterrent, serving to protect the unripe fruit and foliage from generalist herbivores. The concentration of this compound is significantly higher in the unripe, green stage of the tomato and decreases as the fruit ripens and turns red.
For many animals, including most mammals, ingesting large quantities of solanine can cause gastrointestinal distress, leading to symptoms like vomiting and diarrhea. This defensive mechanism explains why many mammalian raids focus on the fruit’s moisture content rather than consuming the entire item. However, certain specialized insects, like the tomato hornworm, have evolved the biochemical machinery to tolerate or metabolize the compound, allowing them to feed heavily on the plant and its unripe fruit without adverse effects.
Analyzing the Evidence: Identifying the Culprit by Damage
The pattern of damage on the plant and fruit provides the clearest evidence for identifying the specific animal responsible. If the entire green tomato is missing, the likely culprits are larger, agile animals like squirrels or raccoons. The presence of gouging teeth marks on fruit near the ground often points to small rodents such as rats or mice, which leave behind discernible parallel grooves from their incisors.
Damage high on the plant, especially if accompanied by stripped foliage, suggests feeding by deer or other tall grazers. Observing the time of the attack can also narrow the possibilities. A raid that occurs overnight suggests a nocturnal feeder like a raccoon or rat, while daytime damage indicates a squirrel or bird. Dark, pellet-like droppings on the leaves or soil, coupled with significant holes in the fruit and defoliation, are the unmistakable signs of a tomato hornworm infestation.