When tomatoes are damaged, accurately identifying the offender is the first step toward effective management. Different pests leave distinct, recognizable calling cards. This guide looks at the specific symptoms of damage, allowing you to pinpoint the exact culprit that is feasting on your tomato plants. Focusing on visual evidence helps implement targeted strategies to protect your remaining crop.
Reading the Clues: Identifying the Damage
Inspect the damaged plant material to diagnose the problem. Look for large, clean bite marks on the fruit or stems, which strongly indicate a mammal with sharp incisors, such as a squirrel or raccoon. If you find foliage that is torn and jagged, especially on higher leaves, it suggests a large herbivore like a deer. Deer lack upper incisor teeth and must rip the plant tissue.
Smaller pests leave behind more subtle evidence. The presence of irregular holes in leaves or fruit, sometimes accompanied by a shiny, silvery trail, points toward soft-bodied invertebrates. If an entire tomato is gone overnight, or if only a partial, messy fruit remains, the damage is likely due to a large nocturnal pest. Pinprick damage, stippling, or cloudy spots on the fruit surface usually signal the activity of sap-sucking insects.
Common Insect and Invertebrate Culprits
The Tomato Hornworm, the larval stage of a sphinx moth, is a notorious defoliator that can strip a plant of its leaves in a matter of days. These large, green caterpillars can reach four inches in length and are perfectly camouflaged. Their presence is betrayed by large, dark green or black droppings, known as frass, found on the leaves or soil beneath the feeding site.
Slugs and snails are frequent offenders, especially in cool, damp conditions, and are easily identified by the silvery mucus trails they leave behind. They chew large, irregular holes in leaves and fruit, often targeting lower leaves or young seedlings. Stink bugs are shield-shaped, typically green or brown, sap-sucking insects that pierce the fruit’s surface. This feeding causes cloudy spots or corky white patches just beneath the skin of ripe tomatoes.
Aphids are tiny, soft-bodied, sap-sucking insects that cluster on new growth and the undersides of leaves. Their feeding action causes leaves to curl, yellow, or become stunted. They excrete a sticky substance called honeydew, which can lead to sooty mold growth. A heavy infestation weakens the plant, reducing its overall yield.
Vertebrate Pests: Mammals and Birds
Larger animals cause damage that is more dramatic, ranging from complete removal of the fruit to substantial plant destruction. Squirrels and raccoons are common culprits, typically leaving behind messy, partial bites on tomatoes still on the vine or on the ground nearby. Squirrels are active during the day, while raccoons are nocturnal. Both may take a single bite out of many different fruits, seemingly just to taste.
Deer primarily pose a threat through browsing on foliage and stems, leaving a ragged edge on the plant where they have pulled off tissue. Because deer lack upper incisors, they tear rather than cleanly cut the plant. Damage is typically observed up to a height of four feet, their natural grazing level. Deer will consume the fruit and foliage when other food sources are scarce or when attracted by the high water content during dry spells.
Birds, such as robins and sparrows, frequently cause small, neat peck marks on ripening fruit, often near the top of the tomato. They seek out the juicy pulp to quench their thirst, especially during hot summer months. These small punctures provide entry points for pathogens and other insects, causing the tomato to rot prematurely.
Integrated Strategies for Pest Management
Once a pest is identified by its signature damage, the appropriate control measures can be deployed, often utilizing a combination of methods. For large mammals and birds, physical barriers offer the most reliable form of protection. Enclosing plants with bird netting, ensuring it is tautly secured, can prevent birds from accessing the fruit.
To deter ground-level rodents and foraging animals, strong fencing that extends into the soil or a smooth metal barrier at least two feet high can be effective. Cultural controls involve modifying the garden environment to make it less appealing to pests. This includes keeping the area free of debris and weeds that harbor slugs and other insects. Crop rotation is another strategy that prevents soil-borne pests from establishing a permanent cycle.
For insect and invertebrate pests, hand-picking remains a sustainable and effective biological control, particularly for large pests like hornworms, which can be dropped into soapy water. Encouraging natural predators, such as braconid wasps or lady beetles, helps to keep pest populations in check without the use of broad-spectrum chemical treatments. Strategically placing a shallow water source nearby can sometimes prevent birds from pecking tomatoes solely for hydration.