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Identification

Bugs on Trees and Shrubs: 13 Types and What to Do

By the Bug Identifier Editorial Team. Updated September 27, 2026. 5 minute read.

Bugs on Trees and Shrubs are one of the most common identification questions we get. Here are 13 you are likely to see.

How to narrow it down

Narrow it down with three quick checks. Count the legs: insects have six, spiders and ticks have eight, and centipedes and millipedes have many more. Check for wings, even folded ones. Then compare size against a coin: a US penny is 19 mm across. Our bug identifier tool does this filtering for you.

The 13 bugs

Bald-Faced Hornet

Bald-Faced HornetDolichovespula maculata15–20 mmHealth risk

A black wasp with ivory-white markings on its face and the tip of its abdomen. It builds large, gray, football-shaped paper nests in trees, shrubs and under eaves.

Tell-tale sign: Black body with a white face and white tail markings. Risk: Bald-faced hornets deliver painful stings and attack in numbers when their nest is disturbed.

European Hornet

European HornetVespa crabro25–35 mmHealth risk

The only true hornet established in North America, a large brown-and-yellow wasp that nests in hollow trees, barns and wall voids. It often flies at night and is attracted to lights.

Tell-tale sign: Large wasp with a reddish-brown head and thorax. Risk: European hornet stings are very painful, and colonies defend their nest, though workers are less aggressive away from it.

Wheel Bug

Wheel BugArilus cristatus25–38 mmCan bite or sting

A large, gray assassin bug with a raised, toothed crest on its back that looks like half a gear wheel. It hunts caterpillars and beetles and is a garden ally.

Tell-tale sign: Semicircular, cog-like crest on the thorax. Risk: Its bite is extremely painful and can take days or weeks to heal, so avoid handling it.

Boxelder Bug

Boxelder BugBoisea trivittata11–14 mmNuisance

A black bug with red-orange lines on its back that feeds on the seeds of boxelder and maple trees. Large groups sun themselves on warm walls in fall before crawling inside.

Tell-tale sign: Black body with three red lines on the thorax. Risk: Boxelder bugs rarely bite and are harmless, but their droppings can stain curtains.

Carpenter Ant

Carpenter AntCamponotus pennsylvanicus6–13 mmNuisance

A large black ant that nests in moist or damaged wood, including window frames, decks and wall voids. It doesn't eat wood but excavates smooth galleries and pushes out sawdust-like debris.

Tell-tale sign: Large ant with an evenly rounded, single-arch thorax. Risk: Carpenter ants can deliver a painful bite and weaken wood over time, but they do not carry disease.

Emerald Ash Borer

Emerald Ash BorerAgrilus planipennis8–14 mmNuisance

A slim, bullet-shaped, metallic green beetle whose larvae tunnel beneath ash tree bark. It has killed hundreds of millions of ash trees across North America.

Tell-tale sign: Bright metallic emerald green body. Risk: Emerald ash borers are harmless to people but lethal to untreated ash trees.

Smokybrown Cockroach

Smokybrown CockroachPeriplaneta fuliginosa30–38 mmNuisance

A large, uniformly dark mahogany cockroach common in the humid Southeast. It lives outdoors in tree holes, mulch and gutters and flies toward lights at night.

Tell-tale sign: Shiny, uniformly dark brown body with no markings. Risk: Smokybrown cockroaches can carry bacteria indoors from mulch and garbage.

Spongy Moth

Spongy MothLymantria dispar35–65 mmNuisance

Formerly called the gypsy moth, an invasive moth whose hairy caterpillars strip the leaves from oaks and other hardwoods. Caterpillars carry paired blue and red dots along the back.

Tell-tale sign: Hairy caterpillars with five pairs of blue dots and six pairs of red dots. Risk: Caterpillar hairs can cause itchy rashes, and heavy outbreaks strip trees of their leaves.

Spotted Lanternfly

Spotted LanternflyLycorma delicatula20–25 mmNuisance

An invasive planthopper spreading through the eastern US that feeds on grapevines, maples and tree of heaven. Its folded gray forewings hide bright red hind wings.

Tell-tale sign: Gray forewings with black spots. Risk: Spotted lanternflies don't bite or sting; they damage vineyards and leave sticky honeydew.

Western Conifer Seed Bug

Western Conifer Seed BugLeptoglossus occidentalis16–20 mmNuisance

A long, brown bug with flattened, leaf-like expansions on its hind legs. It feeds on pine cones in summer and wanders indoors in fall, buzzing loudly when it flies.

Tell-tale sign: Leaf-shaped flat widenings on the hind legs. Risk: Western conifer seed bugs don't bite or sting; they may release a pine-like odor.

Eyed Click Beetle

Eyed Click BeetleAlaus oculatus25–45 mmHarmless

A long, gray-and-black beetle with two large, eye-like spots on its thorax. When flipped over, it snaps a hinge on its body and launches itself into the air with an audible click.

Tell-tale sign: Two large black false eyespots ringed in white. Risk: Eyed click beetles are harmless; the eyespots are a bluff to scare predators.

Luna Moth

Luna MothActias luna80–115 mmHarmless

A large, pale lime-green moth with long, sweeping tails on its hind wings. Adults don't eat and live only about a week to mate.

Tell-tale sign: Pale green wings with long, curved hindwing tails. Risk: Luna moths are completely harmless; adults have no functional mouthparts.

Periodical Cicada

Periodical CicadaMagicicada septendecim25–33 mmHarmless

A black cicada with red eyes and orange wing veins that emerges by the millions every 13 or 17 years. Males fill forests with a loud, pulsing chorus.

Tell-tale sign: Black body with bright red eyes. Risk: Cicadas don't bite or sting; egg-laying can damage branch tips on young trees.

Which ones should you worry about?

3 of the 13 bugs in this guide can bite or sting. The ones to take seriously are bald-faced hornet and European hornet. The rest are harmless or simply a nuisance.

Frequently asked questions

What is the most common one?

Among the bugs in this guide, the bald-faced hornet and European hornet are the ones people ask about most.

Which of these are dangerous?

Bald-Faced Hornet and European Hornet can be medically significant.

How can I identify a bug I found?

Use the free bug identifier tool: choose the number of legs, wings, main color, size and where you found it, and it will list the closest matches.