Tomatoes are one of the most cultivated vegetables in home gardens, sought after for their versatility and flavor. This popularity makes them a frequent target for a variety of animals and insects. Understanding which creatures are responsible for the damage is the first step toward protecting a tomato crop.
Identifying the Main Animals That Eat Tomato Plants
A wide range of wildlife and pests can cause damage, and the pattern of destruction can help identify the culprit. Large browsing mammals, such as deer, cause the most extensive damage, often eating the upper stems, leaves, and green fruit, leaving ragged edges on the remaining parts of the plant. Rabbits and groundhogs target young seedlings and the tender lower leaves, leaving clean-cut stems near the soil surface.
Rodents like squirrels and rats rarely consume the entire plant but damage the ripening fruit itself. Squirrels often take a single bite out of multiple tomatoes, sampling them for moisture, before discarding the partially eaten fruit. Birds, including crows and sparrows, also peck at ripe tomatoes, leaving small, precise holes that invite disease and rot.
Insect pests also pose a significant threat to the foliage and fruit. The Tomato Hornworm, a large green caterpillar, is the most destructive insect, capable of defoliating an entire plant rapidly, leaving behind distinctive dark droppings known as frass. Slugs and snails prefer the moist, shaded lower leaves, chewing irregular, ragged holes and leaving tell-tale slime trails.
Understanding the Toxicity of Tomato Plants
The reason many animals target the fruit rather than the foliage relates to the plant’s natural chemical defense system. Tomato plants belong to the nightshade family and contain compounds called glycoalkaloids, specifically alpha-tomatine and solanine. These alkaloids are concentrated in the green parts of the plant, including the leaves, stems, and unripe green fruit.
The presence of these compounds makes the foliage taste bitter and slightly toxic, acting as a natural deterrent. When ingested in large quantities, these toxins can cause gastrointestinal upset and neurological symptoms. As the tomato fruit ripens and turns red, the concentration of alpha-tomatine decreases, making the fruit palatable and safe for consumption. This explains why animals avoid the plant’s green structure but readily consume the mature fruit.
Practical Methods for Protecting Tomato Crops
Physical barriers offer the most reliable form of protection against larger mammals and determined rodents. For deer, a fence must be at least 8 feet tall to prevent them from jumping over the barrier. Protecting against smaller animals like rabbits and groundhogs requires a fence with a mesh size no larger than one inch, which should also be buried several inches below the soil surface to prevent burrowing.
Protecting the fruit from birds and squirrels often necessitates the use of netting or individual fruit cages. A lightweight, fine mesh netting can be draped over the entire plant, though it must be secured at the base to prevent entry from the ground. Alternatively, individual ripening tomatoes or fruit clusters can be protected by bagging them in small mesh or brown paper bags.
Cultural practices are effective for managing insect pests and ground-dwelling creatures. Hand-picking the large, camouflaged Tomato Hornworms is an effective control method, especially when done early in the morning. Removing the lower leaves of the tomato plant reduces the moist habitat favored by slugs and snails.
Repellents provide a secondary line of defense against mammalian pests but require consistent maintenance. Taste and scent deterrents, such as commercial liquid fence products or homemade hot pepper sprays, can discourage browsing, but their effectiveness diminishes quickly after rain or irrigation. Motion-activated sprinklers can also startle and deter animals like raccoons and deer by using a sudden burst of water when movement is detected.