Garden Pest Identification: Common Bugs and Damage Control

How to identify: Tiny, soft-bodied, pear-shaped insects that cluster on tender stems, buds, and leaf undersides. They may be green, black, yellow, pink, gray, or reddish. Many are wingless, although winged forms can appear when colonies become crowded.

Typical damage: New leaves curl or pucker, shoots become stunted, and sticky honeydew may coat foliage. Black sooty mold often develops on the honeydew. Ant activity can be a clue because some ants feed on honeydew and protect aphid colonies.

Where to look: Check soft new growth first, then unfold curled leaves and inspect the undersides. Roses, beans, peppers, tomatoes, brassicas, herbs, and many ornamentals can host aphids.

Damage control: For light infestations, dislodge colonies with a firm stream of water or prune heavily infested tips. Encourage lady beetles, lacewings, and parasitoid wasps. If pressure remains high, insecticidal soap or horticultural oil can work when applied thoroughly to the pests; follow the product label and avoid spraying heat-stressed plants.

How to identify: Very small white, moth-like adults that flutter up when an infested plant is disturbed. Immature stages are flatter and remain attached to leaf undersides.

Typical damage: Leaves may yellow, become weak, dry, or drop. Like aphids, whiteflies produce honeydew that can lead to sticky foliage and sooty mold. Heavy infestations can reduce flowering and fruit development.

Where to look: Look beneath leaves, especially on tomatoes, peppers, sweet potatoes, ornamentals, and greenhouse or container plants. Gently shake foliage and watch for a cloud of tiny white adults.

Damage control: Remove badly infested leaves, wash sturdy plants with water, and use yellow sticky cards for monitoring rather than as the only control. Conserve natural enemies. Insecticidal soap or horticultural oil may help when coverage reaches the undersides of leaves.

How to identify: Minute, slender insects that may look like tiny dark, tan, or yellow slivers. Adults have narrow fringed wings, but a hand lens is often needed to see details.

Typical damage: Feeding produces silvery streaks, pale scarring, distorted petals, bronzed patches, and tiny dark specks of excrement. Flowers may open poorly and fruit can develop surface scars.

Where to look: Inspect blossoms, buds, folded leaves, and leaf undersides. Tap flowers over a sheet of white paper to dislodge hidden thrips.

Damage control: Remove heavily damaged flowers or leaves, control nearby weeds that may host thrips, and avoid unnecessary broad-spectrum insecticides that can remove predators. Targeted soaps, oils, or other products labeled for thrips may be useful if populations remain damaging.

How to identify: Spider mites are tiny arachnids, not insects. Common two-spotted spider mites are extremely small and often yellowish or tan with darker spots. Fine webbing appears when populations become high.

Typical damage: Leaves develop many tiny pale dots (stippling), then look bronzed, bleached, or dusty. Severe feeding causes leaf drop and plant decline. Hot, dry weather often makes outbreaks worse.

Where to look: Look on the undersides of stressed leaves. Hold white paper beneath a leaf, tap the foliage, and watch for tiny moving dots.

Damage control: Reduce plant stress with consistent watering, rinse foliage to knock mites and webbing off sturdy plants, and protect predatory mites and other natural enemies. Horticultural oil or insecticidal soap can help when applied directly and repeatedly according to label directions.

How to identify: Scale insects often look like small brown, tan, gray, or white bumps attached to stems or leaves. Mealybugs are soft-bodied relatives covered in white, cottony wax, often gathering in leaf joints and protected crevices.

Typical damage: Sap loss causes yellowing, weak growth, leaf drop, and dieback. Many species produce honeydew, so sticky leaves, ants, and sooty mold may appear.

Where to look: Check woody stems, leaf veins, branch crotches, and undersides. On container plants, inspect tight spaces around petioles and new growth.

Damage control: Prune or wipe off small colonies, isolate heavily infested container plants, and manage ants that protect honeydew producers. Horticultural oils can be useful against exposed or immature stages when the label allows their use on the plant.

How to identify: Tiny, shiny beetles that are often black, bronze, blue-black, or striped. They jump quickly when disturbed, which is how they get their name.

Typical damage: Adults chew many small round “shot holes” through leaves. Seedlings can be stunted or killed when pressure is heavy, while larger established plants often tolerate moderate feeding.

Where to look: Watch young brassicas, eggplant, radish, arugula, potato, and other seedlings. Approach slowly and look for tiny beetles hopping from the foliage.

Damage control: Use floating row covers early where practical, keep weeds down, and protect seedlings during their most vulnerable stage. If treatment is needed, choose a product specifically labeled for flea beetles on the crop and follow all harvest-interval instructions.

How to identify: Small yellow beetles marked with either black stripes or black spots. Adults are easy to notice on flowers and leaves of cucumber-family crops.

Typical damage: They chew holes in leaves, blossoms, and fruit surfaces. Larvae feed on roots. More importantly, some cucumber beetles can spread bacterial wilt, so plants may suddenly wilt after feeding injury.

Where to look: Inspect cucumbers, melons, squash, pumpkins, and gourds, especially flowers and young plants. Look early in the morning when beetles may be less active.

Damage control: Use row covers on young plants until flowering, remove severely diseased plants, and keep the garden free of volunteer cucurbits and weeds that provide habitat. Handpick small populations. Use labeled insecticides only when beetle pressure or disease risk justifies treatment.

How to identify: About half an inch long with a metallic green head and thorax, coppery wing covers, and small white hair tufts along the sides of the abdomen.

Typical damage: Adults eat tissue between leaf veins, leaving a lace-like or skeletonized leaf. They also chew flowers and soft fruit. Their larvae are white grubs that feed in soil, especially turf.

Where to look: Check roses, grapes, beans, raspberries, fruit trees, and many ornamentals during the day. Adults often feed in groups on sunny foliage.

Damage control: For manageable numbers, handpick beetles into soapy water in the cool morning. Protect high-value plants with barriers where practical. Avoid placing lure traps beside susceptible plants because they can draw additional beetles into the area. Treat only when damage warrants it and use crop-labeled products.

How to identify: Rounded yellow-orange beetles with bold black stripes running lengthwise on the wing covers. Larvae are soft, reddish to orange, with rows of black spots.

Typical damage: Adults and larvae chew potato-family foliage rapidly. Heavy infestations can defoliate potatoes, eggplants, and sometimes tomatoes, reducing plant vigor and yield.

Where to look: Check potato leaves for adults, orange egg clusters on leaf undersides, and groups of reddish larvae. Damage can increase quickly as larvae grow.

Damage control: Handpick adults and larvae in small gardens, crush egg masses, rotate crops when space allows, and remove volunteer potatoes. If insecticides are needed, rotate effective modes of action according to label guidance because this pest is well known for developing resistance.

How to identify: Cabbage worms are velvety green caterpillars associated with white butterflies. Cabbage loopers are green caterpillars that move by arching their bodies in a looping motion.

Typical damage: Both chew irregular holes in cabbage, kale, broccoli, cauliflower, collards, and other brassicas. They may feed inside heads and leave greenish droppings among leaves.

Where to look: Inspect leaf undersides, inner leaves, and the center of developing heads. Look for green caterpillars that blend closely with foliage.

Damage control: Handpick caterpillars and eggs, use insect netting or row covers before adults lay eggs, and keep brassica weeds controlled. Bacillus thuringiensis var. kurstaki (Bt) can be effective against young caterpillars when used exactly as labeled.

How to identify: Large green caterpillars that can reach several inches long. They have diagonal white markings and a horn-like projection at the rear. Their size is dramatic, but their camouflage makes them easy to miss.

Typical damage: Hornworms can strip leaves and chew green fruit on tomatoes, peppers, eggplants, and related plants. Dark droppings often collect on leaves or the soil beneath feeding sites.

Where to look: Follow fresh defoliation and droppings upward through the plant. Check stems carefully because the caterpillar often aligns itself with them.

Damage control: Handpick in home gardens. If a hornworm is covered with small white parasitoid wasp cocoons, leave it in place because the wasps are beneficial and will help reduce future hornworms. Bt can work best on younger larvae when labeled for the crop.

How to identify: Smooth, thick caterpillars in gray, brown, tan, green, or black. Many curl tightly into a C-shape when disturbed and hide in soil or plant debris during the day.

Typical damage: Young seedlings are clipped at or just above the soil line, sometimes disappearing overnight. Some species also climb plants to feed on leaves, buds, or fruit.

Where to look: Inspect around freshly damaged seedlings in the evening or gently search the top inch of soil within about a foot of the plant.

Damage control: Remove larvae by hand, clear weeds and plant residue that provide hiding or egg-laying sites, and use cardboard or foil collars around valuable transplants. Home-garden insecticides are often unnecessary when the problem is found early.

How to identify: Leaf miners are the larvae of several flies, moths, beetles, or sawflies. The insect is usually hidden inside the leaf, so the mine pattern is more useful than the adult for identification.

Typical damage: Feeding creates pale, winding serpentine tunnels or larger blotchy patches within the leaf. The damaged tissue later turns tan or brown. Leafy greens can become unmarketable or unpleasant to eat even when plant growth is not badly affected.

Where to look: Inspect spinach, chard, beets, beans, tomatoes, cucumbers, onions, and other hosts for fresh pale mines. Hold leaves toward the light to see larvae or frass inside some mines.

Damage control: Remove infested leaves when damage is limited, control host weeds, and use fine insect netting before adult flies reach the crop. Once larvae are inside the leaf, contact sprays usually cannot reach them, so prevention and early removal are more effective.

How to identify: Flattened, gray-brown to dark brown insects found on squash-family plants. Young nymphs are smaller and often gray or light green with dark legs. Bronze to brown egg clusters are commonly attached to leaf undersides.

Typical damage: Feeding causes yellow spots, wilting, blackened tissue, and vine decline. Young squash and pumpkin plants are more vulnerable than large, established vines.

Where to look: Inspect leaf undersides for egg clusters and nymph groups, then check the plant crown, base, and debris where adults hide.

Damage control: Crush or remove egg clusters, handpick adults and nymphs, remove old cucurbit debris after harvest, and use boards as temporary hiding traps that can be checked each morning. Target young nymphs if a labeled pesticide becomes necessary, because adults are harder to control.

How to identify: Shield-shaped bugs that may be green, brown, or mottled. Different species vary in markings, and both adults and nymphs can feed on garden crops.

Typical damage: Piercing feeding can cause dimples, corky spots, discoloration, misshapen fruit, aborted seeds, or distorted pods. Tomatoes, peppers, beans, corn, and many fruits may be affected.

Where to look: Look on fruit clusters, leaf undersides, and weeds around the garden. Egg masses are often laid in tidy groups on leaves.

Damage control: Handpick small numbers, remove weed hosts, and keep row covers on vulnerable crops when compatible with pollination. If chemical control is needed, choose a product labeled for both the crop and the specific pest and apply only where damage justifies it.

How to identify: Soft-bodied mollusks that move on a muscular foot and leave a mucus trail. Snails carry an external shell; slugs do not. They are most active in cool, damp conditions and at night.

Typical damage: Irregular ragged holes appear in leaves, flowers, and ripening fruit. Seedlings can be eaten to the ground. Dried silver-colored slime trails are a useful clue.

Where to look: Check under pots, boards, stones, dense mulch, low foliage, and shady groundcovers after dark or early in the morning.

Damage control: Reduce overly damp hiding places, improve air circulation, water in the morning, handpick at night, and use boards as traps. If bait is needed, iron phosphate products can be a lower-risk option when used according to the label.

How to identify: Elongated brown insects with a distinctive pair of forceps-like pincers at the rear. They hide during the day and become active at night.

Typical damage: Earwigs are omnivores. They may chew seedlings, soft fruit, flowers, corn silks, or tender leaves, but they also eat aphids and other small pests. Damage is usually irregular and is often confused with slug or caterpillar feeding.

Where to look: Look beneath boards, pots, mulch, and garden debris. Roll up damp newspaper or corrugated cardboard overnight to see whether earwigs are using it as shelter.

Damage control: Only control them when feeding damage is clearly significant. Reduce damp shelter near vulnerable plants, trap and remove concentrated populations, and avoid killing them automatically because they can also act as predators.

How to identify: Creamy white, C-shaped larvae with brown heads and three pairs of legs near the head. Several beetle species have grub-like larvae in the soil.

Typical damage: Root feeding can cause weak growth, wilting, poor establishment, or patches of turf that lift easily because roots have been pruned. Container and garden plants may decline even when watering seems adequate.

Where to look: Dig carefully around the root zone of a stressed plant or lift a small section of affected turf. Count larvae rather than assuming one grub is responsible for the entire problem.

Damage control: Improve plant vigor and avoid unnecessary treatment when numbers are low. Management depends heavily on the grub species, crop, timing, and local thresholds, so confirm identification before applying a soil insecticide or biological treatment.