Tomato Pests. Common Bugs on Tomato Plants, How to Identify Them, And What to Do Next

Start with where they are and what the leaves look like. Pear-shaped insects clustered on tender growth are often aphids. Tiny white insects that fly when foliage is disturbed point toward whiteflies. Moving specks with fine stippling suggest spider mites, while very slender insects hiding in flowers and new growth can be thrips. Russet and broad mites are much harder to see and are usually diagnosed from bronzing or distorted growth plus magnification.

Sticky tomato leaves usually mean honeydew from a sap-feeding pest. Aphids and whiteflies are the first pests to check. Look under leaves and around tender shoots for colonies, pale shed skins, whitefly nymphs, or adults. Ants moving up and down the plant can be another clue because they feed on honeydew. Black sooty mold may develop on heavy honeydew deposits.

Fine pale stippling is a classic spider mite symptom, especially when it begins on leaf undersides during hot, dry weather. As feeding increases, leaves can turn bronze, dry, and brittle, and fine webbing may appear. Russet mites can also bronze tomato foliage and stems, but their damage is usually more uniform and the mites themselves are too small to confirm without strong magnification.

Several pests can curl tomato leaves. Aphids feeding on expanding leaves can leave new growth puckered or curled. Russet and broad mites can distort tender growth and create bronzing. Thrips can scar and deform young tissue. Whiteflies can weaken and distort foliage, and some whiteflies and thrips can transmit viruses that also curl leaves. Check for the pest itself before treating a curled leaf as an insect problem.

Leaf undersides are one of the best places to scout. Aphids form colonies there, whitefly eggs and nymphs develop there, spider mites feed and lay eggs there, and thrips may shelter along veins or tucked areas. Turn over leaves from the lower, middle, and upper canopy instead of checking only the top surface.

A cloud of tiny white insects lifting off when you tap or brush the foliage strongly suggests whiteflies. Adults quickly settle back onto leaf undersides, where eggs and flattened nymph stages are easy to miss. Sticky honeydew, yellowing, sooty mold, and plant weakness can build as populations increase.

Silver or bronze streaks and scars are strongly associated with thrips feeding. Thrips scrape plant cells and feed on the exposed contents, leaving silvery patches that may contain tiny black fecal specks. Check flowers, buds, tender leaves, and protected folds because thrips often hide where a quick glance misses them.

Large missing sections or whole leaves disappearing point toward a chewing pest rather than a mite, aphid, whitefly, or thrips. Tomato and tobacco hornworms can remove entire leaves and leave dark blocky droppings below the feeding site. Cutworms, fruitworms, armyworms, flea beetles, slugs, and other chewers can create different hole patterns. Find the pest before choosing a control method.

Lost Coast Plant Therapy is a minimum risk pesticide made with natural and organic ingredients that controls supported soft bodied pests on contact. On tomatoes, the most relevant supported pests include aphids, whiteflies, spider mites, russet mites, broad mites, and thrips. Cornell CALS greenhouse trials reported 95% +/- efficacy against total western flower thrips and all soft bodied insects in the strongest treatment after five applications.

Hornworms, stink bugs, cutworms, and other chewing or hard-bodied pests usually require another management approach.

A quick inspection at least once a week is a useful baseline, and every few days is better when plants are flowering, growing quickly, under greenhouse cover, or experiencing hot dry weather that favors mites. Check new growth, flower clusters, leaf undersides, stems near the soil line, and developing fruit. Once you find a pest, inspect more often so you can tell whether the population is shrinking, stable, or spreading.