Webs on Tree Branches: Tent Caterpillars or Webworms?

Silky webs in your trees are most likely eastern tent caterpillars if it's spring and the web sits in a branch fork, or fall webworms if it's late summer and the web wraps the tips of branches. Both look alarming but rarely do lasting harm to a healthy tree — and whatever you do, never try to burn a nest out of a tree.

Most likely causes

  • Eastern tent caterpillars — dense silk tents in branch crotches in spring
  • Fall webworms — loose webbing enclosing leaves at branch tips in late summer
  • Ordinary spider webs — no caterpillars inside, harmless and even helpful
  • Mite or barklice webbing — fine silk sheets on bark or leaves, mostly cosmetic

Compare the possible causes

Possible cause Key signs When it happens How likely
Eastern tent caterpillars A compact, layered silk tent wedged into the fork where branches meet, with dark, fuzzy caterpillars visible inside or marching along branches Early to mid spring, right as leaves emerge; favorites are wild cherry, apple, and crabapple Very common
Fall webworms Loose, gauzy webbing that encloses whole clusters of leaves at the ends of branches, often with skeletonized leaves inside Late summer into fall; common on hickory, walnut, sweetgum, mulberry, and many shade trees Very common
Spiders Classic orb webs, funnel webs, or sheet webs strung between branches with no caterpillars, no enclosed leaves, and no chewing damage Any time from spring through fall, most noticeable on dewy fall mornings Common
Spider mites or barklice Very fine silk sheeting over bark or across leaf surfaces without any tent structure, sometimes with tiny insects grazing beneath it Hot, dry midsummer for mites; late summer for barklice Less common

Visual clues to check

  • Note where the web sits: a branch crotch means tent caterpillars; branch tips mean fall webworms; strung between branches with no leaves inside means spiders
  • Check the calendar: webs in April and May point to tent caterpillars; webs in August and September point to webworms
  • Look inside the web: dozens of fuzzy caterpillars confirm one of the two nest-builders; a single spider means a harmless web
  • Inspect leaves near the web: chewed or skeletonized leaves inside the silk point to webworms; stripped branches near a crotch tent point to tent caterpillars
  • Scan twigs in winter: dark, varnished-looking bands wrapped around pencil-thin twigs are tent caterpillar egg masses you can prune off before spring
  • Count the webs across the tree: one or two nests on a mature tree is normal; a small or newly planted tree covered in webs deserves action

The causes in detail

Eastern tent caterpillars

Tent caterpillars hatch in early spring from a dark egg band on a twig and build their tent in a branch crotch, enlarging it as they grow. They leave the tent to feed on nearby foliage and return at night and in bad weather — which is exactly why removal works best early in the morning or on cool, rainy days when the colony is home. A healthy tree can lose a lot of spring leaves to them and releaf by summer.

Fall webworms

Fall webworms do the opposite of tent caterpillars: they wrap the branch tips rather than the crotches, and they feed inside the web, expanding it over the leaves as they eat. The timing is the other giveaway — big webs appearing in August and September are webworms. Because the tree has already banked most of its energy for the year by then, webworm damage is almost entirely cosmetic, and many arborists recommend simply leaving small webs alone.

Spiders

A web with a single spider and no caterpillar colony inside isn't a pest problem at all. Spiders don't eat leaves — they eat the insects that do, including moths whose caterpillars damage trees. Large numbers of webs glinting in the grass and shrubs on cool fall mornings are simply the year's spider population becoming visible, not an infestation.

Spider mites or barklice

Not all tree webbing comes with caterpillars. Spider mites can silk over stressed foliage during hot, dry spells, and barklice — harmless insects that graze on fungi and algae — sometimes spin remarkably neat silk wraps around trunks and limbs. Barklice webbing needs no treatment at all; it typically disappears within weeks, and the insects are actually cleaning the bark.

When to worry

  • A young or newly planted tree losing most of its leaves — small trees have fewer reserves and benefit from prompt web removal
  • Complete defoliation of the same tree two or more years in a row, which can weaken even a mature tree
  • Webs high in a large tree that can't be reached safely from the ground — a job for an arborist, not a ladder
  • Caterpillars migrating in large numbers across driveways, patios, or siding when they leave the tree to pupate

What to do now

  1. For reachable tent caterpillar nests, wait for early morning or a cool, rainy day when the colony is inside, then pull the tent out with a gloved hand or twist it out on a stick and drop it into soapy water
  2. Prune out webworm webs at branch tips by clipping the webbed twigs into a trash bag — or tear the web open with a stick so birds and wasps can reach the caterpillars
  3. Leave spider webs alone; the spider is eating pest insects for you
  4. In winter, check cherry, apple, and crabapple twigs for the dark egg bands of tent caterpillars and prune them off before they hatch
  5. Keep defoliated trees watered through the season so they can releaf without added drought stress
  6. For big webs high in a valuable tree, or a small tree being overwhelmed, call a certified arborist rather than climbing with tools

What not to do

  • Never burn a web or nest out of a tree — the classic torch-on-a-pole trick kills the branch, scars the trunk, and starts house and brush fires every year; the fire damage is always worse than the caterpillars
  • Don't spray insecticide into the web — the silk shields the caterpillars, so the spray mostly misses them and hits everything else
  • Don't prune out large limbs just to remove a web; losing the branch hurts the tree more than the caterpillars would
  • Don't climb ladders with pruning tools to reach high webs — leave high work to professionals
  • Don't panic-treat a mature tree over cosmetic late-season webbing; fall webworms rarely affect the tree's health

Frequently asked questions

Will web caterpillars kill my tree?

Almost never on their own. A healthy, established tree can be heavily defoliated by tent caterpillars in spring and grow a new set of leaves within weeks, and fall webworm feeding happens so late in the season that the tree has already stored most of its energy. The real risk cases are small young trees and trees stripped several years running.

What's the difference between tent caterpillars and fall webworms?

Location and season. Eastern tent caterpillars build a dense tent in the fork of branches in spring and leave it to feed; fall webworms wrap loose webbing around the tips of branches in late summer and feed inside it. If the leaves are enclosed within the silk, you're looking at webworms.

Can I just leave the webs alone?

Often, yes. On a mature tree, both pests are largely cosmetic, and birds, predatory wasps, and parasitic flies take a heavy toll on the caterpillars naturally. Remove nests when the tree is young, when defoliation is severe, or when the webs are simply where you can't stand looking at them — by hand or by pruning, not by fire or spray.

When is the best time to remove a tent caterpillar nest?

Early morning, late evening, or during cool rainy weather — that's when the whole colony is inside the tent rather than out feeding. Pull or twist the tent out with gloves or a stick and drown it in a bucket of soapy water. Removing a tent at midday on a warm day misses most of the caterpillars.

Related yard clues

Bugs & Eggs Brown Egg Sacs on Branches: Mantis, Lanternfly, or Moth? A brown egg case on a branch is either very good news or very bad news: praying mantis egg cases (oothecae) are beneficial and should be left alone, while spotted lanternfly and spongy moth egg masses are invasive pests you should destroy — and in many states, report. Texture and shape tell them apart, so identify before you scrape. Read the guide → Bugs & Eggs Green Caterpillars on Plants: Which One Is Eating Yours? The green caterpillar on your plants is most likely a cabbage worm if it's on broccoli or kale, a tomato hornworm if it's large and has a tail spike, or a sawfly larva if it's on roses. Which plant is being eaten narrows it down fast, and handpicking plus row covers handle most of them — no spraying required. Keep in mind that some green caterpillars grow up to be butterflies worth keeping around. Read the guide → Bugs & Eggs Small White Cocoons on Plants: Don't Destroy Them Yet Small white cocoons on your plants could be braconid wasp cocoons, mealybugs, spittlebug foam, or ordinary moth pupae — and the difference matters, because braconid cocoons are one of the best things you can find in a garden. If the white capsules are riding on the back of a fat green caterpillar, leave everything exactly where it is: tiny parasitic wasps are already destroying that pest for you. Read the guide →

Still not sure? Compare with these clues

Plant Damage Skeletonized Leaves: What Eats Everything but the Veins? Leaves chewed down to a lacy network of veins are usually the work of Japanese beetles or sawfly larvae such as rose slugs and pear slugs. Japanese beetles feed in plain sight in daytime swarms during midsummer, while sawfly larvae hide on leaf undersides and 'window-pane' the leaf from below — and stippled, bleached leaves that aren't actually eaten point to lace bugs instead. Read the guide → Plant Damage Leaves Chewed From the Edges: How to Read the Bite Marks Leaves eaten inward from the edges are usually caterpillars, grasshoppers, or — if the edges show neat crescent-shaped notches — adult weevils feeding at night. When whole leaf sections or stems are missing, the cut itself is the clue: a clean angled snip means rabbits, while ragged torn edges mean deer. Read the guide → Bugs & Eggs Tiny White Bugs Under Leaves: What They Are, What to Do Tiny white bugs on the undersides of leaves are most often whiteflies, mealybugs, woolly aphids, or spider mites. The quickest test is to disturb the plant: whiteflies scatter into the air instantly, while mealybugs and woolly aphids stay put in cottony patches. All of them respond to gentle controls — a hard spray of water and insecticidal soap — so there's no need to reach for harsh chemicals. Read the guide → Mushrooms & Growths Shelf Fungus on a Tree Trunk: A Sign of Decay Inside the Tree A shelf or bracket fungus growing from a living tree's trunk is a red flag: it means the fungus has been decaying wood inside the tree, often for years, before producing that visible 'conk.' The tree may still look healthy, but internal decay weakens its structure — so the right move is an assessment by an ISA-certified arborist, not knocking the fungus off. Read the guide →