Plant Problem Diagnostic
Eastern Tent Caterpillar vs. Fall Webworm
The short answer
The two webs people confuse are easy to separate by location and season: eastern tent caterpillar builds a dense, silvery tent in the fork or crotch of a branch in spring, while fall webworm builds a loose, dirty web out at the branch tips that encloses the leaves in late summer and fall.
Another giveaway is behavior: tent caterpillars leave their tent to feed and only rest inside it, so the tent stays clean, whereas fall webworm larvae feed inside their web and expand it over the foliage as they go.
On an established, healthy tree both are mostly a cosmetic nuisance; the tree tolerates the feeding and re-leafs, so control is optional.
Where you want to act, the simplest fix for either one is to prune out or pull down the web by hand while the caterpillars are inside, rather than spraying or burning.
Read the web: fork vs. branch tip
Location is the fastest tell. UNH Extension describes the eastern tent caterpillar's web as thickly constructed in the forks and crotches of trees, while the fall webworm's web is dirty and loosely woven and encloses the branches out toward their ends.
Iowa State adds that eastern tent caterpillar forms silvery-gray webs usually at the fork of a major branch, and the tent starts small and enlarges as the caterpillars feed and grow.
So a compact silk tent nestled where two branches meet points to tent caterpillar, and a ragged web wrapped around the leaves at the tip of a branch points to fall webworm.
Read the calendar and the caterpillar
Timing separates them just as cleanly: eastern tent caterpillar appears in spring, while fall webworm appears in summer and fall, which is where its name comes from.
The caterpillars look different too. UNH describes the eastern tent caterpillar as about two inches long with sparse hairs, black with white and blue markings and a distinctive white stripe down the middle of the back, while the fall webworm is about one and a half inches long, very hairy, with a dark head.
Their host trees overlap on ornamentals: Iowa State notes eastern tent caterpillar prefers apple, crabapple, wild plum, and cherry, and it produces a single generation each year, with eggs laid in summer that do not hatch until the following spring, usually in April.
✔ One clean way to remember it: tent caterpillars pitch their tent in spring and only sleep there, while fall webworms wrap their food up in the web later in the year and eat inside it.
Why you can usually relax
Both insects tend to alarm people more than they harm the tree. Iowa State points out that eastern tent caterpillars feed on the host foliage for only about four to six weeks, and that the caterpillars and their silk webbing are harmless to people.
A vigorous, established shade or fruit tree re-leafs after the feeding passes, so the damage is largely cosmetic and rarely threatens the tree's life.
The main exception is a young, newly planted, or already stressed tree, where heavy defoliation is worth heading off with prompt removal of the webs.
How to remove the webs
Early detection is what keeps either pest from stripping foliage. UNH recommends destroying the nests by pruning them out or removing them by hand, noting that a stick inserted into a large web and twisted will loosen it.
Iowa State advises removing and destroying tents and caterpillars as soon as they are noticed, and timing the job for early morning, late evening, or cool rainy days when the caterpillars are gathered inside the tent.
- 1Catch it early — Scout for small tents in spring (tent caterpillar) or webbed branch tips in late summer (fall webworm) so you can act before much foliage is lost.
- 2Prune or pull it down — Prune out the infested branch tip, or twist the web onto a stick and pull it down while the caterpillars are inside during cool or low-light hours.
- 3Skip the fire — Do not burn webs in a standing tree; it damages the bark and living wood far more than the caterpillars do. Reserve any insecticide for hard-to-reach or unusually heavy infestations, per UNH.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- UNH Extension — Fall Webworm and Eastern Tent Caterpillar Fact Sheet — Verifies the fall webworm's dirty, loosely woven web encloses branches with larvae feeding within it, while the eastern tent caterpillar's thickly constructed web is in the forks and crotches of trees and the larvae do not feed inside it but congregate there at night and in rainy weather; that fall webworm appears in summer and fall and eastern tent caterpillar in spring; larval descriptions (fall webworm about 1.5 inches, very hairy, dark head; eastern tent caterpillar about 2 inches, sparse hairs, black with white and blue markings and a white dorsal stripe); and management by destroying nests through pruning or hand removal, with pesticides reserved for hard-to-reach or heavy infestations.
- Iowa State University Extension — Eastern Tent Caterpillar — Verifies silvery-gray webs usually at the fork of a major branch that enlarge as caterpillars grow; preference for apple, crabapple, wild plum, and cherry; one generation per year with eggs laid in summer that hatch the following spring, usually in April; feeding for four to six weeks; that caterpillars and silk webbing are harmless to people; and removing and destroying tents and caterpillars as soon as noticed, ideally in early morning, late evening, or on cool rainy days when caterpillars occupy the tents.