How to Get Rid of Fall Webworms

Pull the nest off the tips while the caterpillars are still inside. Dump the silk in a bucket of soapy water. A rake or a strong hose that tears the web open is enough. Birds and wasps finish what you started. Do not burn the nest on the tree.

Fall webworm is a native moth, Hyphantria cunea. People call the silk a tent. Then keep saying fall webworm. In late summer, look at the outer tips of a pecan, walnut, or sweetgum. A loose, dirty web wraps the foliage. Hairy pale caterpillars eat inside that web. A healthy tree already stored this year's food. One late summer of webs is looks, not a take-down.

Pull or prune a nest you can reach. Tear open what you cannot pull.
Confirm: tips, late summer, caterpillars inside.
A spray after the web is already brown is too late. Nobody is home.

Pull the nest off the tips, or prune that tip

The colony lives in the silk. If you can reach it, wrap the web around a rake, a forked stick, or a pole with a nail across the end, and twist. The caterpillars come with it. Drop the mass in soapy water. Wear gloves. The hairs can itch. Early morning or evening, they sit still.

On a small pecan or a newly planted walnut, prune the tip if that cut will not wreck the shape. The silk is temporary. A hard prune on a mature tree is permanent. Do not reshape a canopy to chase a nest that rain will take.

A hole in the web is still useful. Birds and wasps cannot hunt through intact silk. A strong hose that tears the nest open does the same job. Fail if you torch the nest on the tree. Fire injures bark and buds worse than the caterpillars, and it is a fire hazard.

Should I burn fall webworm nests?

No. Fire injures bark and buds worse than the caterpillars, and it is a fire hazard. Pull, prune, or tear the silk open instead.

A healthy tree already stored this year's food

They eat late, after the leaves have done most of their work. They eat the leaf, not next year's buds. A mature pecan, oak, or walnut usually leafs out fine in spring. The web looks worse than the injury.

Act when the tree is young and most of the canopy is inside silk, or when the same pecan is stripped year after year in drought. A couple of nests on a bearing pecan is looks. Most of the canopy webbed is the year to pull, or to spray while the worms are still small.

Water through dry weeks. Do not take the tree down for one August of dirty silk. When the web turns brown and empty, feeding is finished. Rain and snow take the silk. Leave it.

Will fall webworms kill my tree?

A healthy mature pecan, oak, or walnut usually leafs out fine after one late summer of this feeding. They eat the leaf, not next year's buds. A young tree, or the same canopy stripped year after year in drought, is the real risk.

Will the webs fall off on their own?

Yes. Once the web is brown and empty, feeding is finished. Rain and snow take the silk. A spray will not pull it down.

The web sits on the tips, and the caterpillars eat inside it

Confirm is location and season, not the color of the head. Loose silk wrapping leaves at the outer tips, from midsummer into fall. Many hairy caterpillars inside, pale green to yellow, with a black or red head and long hairs from bumps along the back. About an inch when grown. Tap the nest. They jerk together.

The web fills with frass, cast skins, and chewed leaves. That mess is this moth. They expand the silk as they eat. After the last molt they may wander, then drop and pupate in litter, bark, or soil. Eggs sit in a hair-covered mass on the underside of a leaf. The moth is white, sometimes with dark spots.

Black-headed colonies often spin a thinner web. Red-headed colonies spin a denser one. Both are this moth. One generation in the North. Two or more in the South. The fall brood is the one people notice. They do not eat pine needles.

Where you see it	What it is	Try this
Loose dirty web wrapping branch tips, late summer, many hairy caterpillars inside	Fall webworm	Pull or prune; wait on a healthy tree
Dense silk in a branch fork, spring, larvae leave to feed	Tent caterpillar leftover	See tent caterpillar — not this nest
Individual spindle of silk plus needles, often on arborvitae or juniper	Bagworm leftover	See bagworm — not this nest
Looping hairless worm, no communal nest, spring	Fall cankerworm leftover	See fall cankerworm — not this nest
Only honeylocust or mimosa leaflets webbed brown	Mimosa webworm leftover	Different moth — not this nest
Brown empty web, no caterpillars	Feeding finished	Leave it; rain takes the silk

What do fall webworm caterpillars look like?

Hairy, pale green to yellow, about an inch when grown, with a black or red head. Color of the head is not a different moth. Tap the nest. They jerk together.

A dense tent in a fork in spring is a different moth

Eastern tent caterpillars spin a thick nest in the V of a cherry or apple in spring, then leave the tent to feed. That is not a dirty bag of silk on the tips in August. See tent caterpillar. Do not run their egg-scrape here.

Bagworms are individual spindles of silk dressed in the plant's own foliage, often on arborvitae and juniper. See bagworm. Do not pick bags here.

Fall cankerworm is a looping inchworm in spring. It drops on a single silk thread. It does not build a communal nest. See fall cankerworm. Do not run a sticky trunk band here.

If only honeylocust or mimosa leaflets are webbed and brown, that is mimosa webworm, a different moth. Do not run its spray here.

Are fall webworms the same as tent caterpillars?

No. Fall webworm wraps the tips in late summer and eats inside the silk. Eastern tent caterpillar spins a dense nest in a fork in spring and leaves the tent to feed. See tent caterpillar.

Are fall webworms bagworms?

No. Bagworms live one to a spindle of silk dressed in the plant's own foliage, often on arborvitae and juniper. Fall webworm is a communal dirty web on deciduous tips. See bagworm.

Bt only while the webs are still small

Bacillus thuringiensis (Bt, the kurstaki strain) has to be eaten. Spray when the nests are still small, the caterpillars are still young, and you can wet the leaves they are eating. Tear the silk first, or use enough pressure to push through it. A second pass about seven to ten days later, because Bt does not last. Follow the label in your hand.

A fog on the outside of a thick nest does not reach the worms. A spray after the web is brown and empty will not rewind the leaves, and it will not pull the silk down. Skip the brand aisle if a rake would have finished the nest. Fail if the finish is a fog on a brown empty web.

Does Bt kill fall webworms?

It kills young ones that eat treated leaves. Use it while the webs are still small, after you tear the silk or push spray through it. It will not pull an empty brown web off the tree.

Confirm the tip web, then pull, wait, or spray young

Confirm this moth. Late summer. Loose silk on the tips. Hairy caterpillars eating inside. They jerk together when you tap.
If this is a nest or two on a healthy mature tree, wait, or tear the silk open for birds and wasps. Water through dry weather.
Pull or prune a nest you can reach. Twist it off. Dump it in soapy water. Do not burn it on the tree.
Bt only while the webs are still small and you can wet the leaves inside, if the tree is young, already stressed, or most of a pecan canopy is inside silk.

How do I get rid of fall webworms?

Pull the nest off the tips, or prune that tip, while the caterpillars are still inside. Dump the silk in soapy water. Tear open what you cannot reach. Do not burn the nest on the tree. Bt only while the webs are still small.

FAQ

Do fall webworms bite people?

No. They eat leaves. They do not sting. The hairs can itch on sensitive skin, so wear gloves when you pull a nest.

Will dish soap kill fall webworms on the pecan?

A kitchen mix sprayed into the canopy is leftover. Dump pulled nests in soapy water. Do not wash a tree with dish detergent. That can burn the leaves.

Will fall webworms come back next year?

They overwinter as pupae in litter, bark, or soil under the tree, so the same pecan can show nests again. Numbers rise and fall. Predators catch up after a heavy year. Pulling this year's nest still helps this tree.

Do fall webworms eat pecans or walnuts?

They eat leaves, not the nuts. Heavy defoliation on a fruit or nut tree can sunburn what is hanging there. The crop job is still the canopy, not a worm in the husk.