Drive through any North Texas neighborhood in October and you will see them: big silky white nests draped over the branch tips of pecans, elms, and redbuds. They look like Halloween decorations someone forgot to take down. They are fall webworm nests, and they send more homeowners into a panic than almost anything else that happens to trees in the fall.
Here is the part most people need to hear first: for a healthy, mature tree, those webs are mostly a cosmetic problem. That does not mean you ignore them. Young trees, stressed trees, and trees that get stripped year after year can take real damage. And if you grow pecans for the nuts, a heavy infestation matters more. This guide covers what fall webworms are, what they are not, and the fixes that actually work.
What fall webworms are (and what they are not)
Fall webworms are the larvae of a native moth, Hyphantria cunea. Texas gets two generations a year. The first shows up in early summer and stays small. The second generation builds the big nests you see in September and October, and that is the one people notice.
The larvae spin a silk nest that encloses the branch tips, then feed on the leaves inside it. The nest grows as they eat. A mature nest can swallow several feet of branch. When they finish feeding, the larvae drop to the ground and pupate in the soil or in bark crevices, and the empty nest weathers away over winter.
Two look-alikes cause most of the confusion. Eastern tent caterpillars show up in spring, build their tents in the crotches of branches, and crawl out to feed. Fall webworms stay inside their nests. And bagworms are individual pinecone-looking cocoons that hang on evergreens, a totally different pest with a totally different fix. If you are seeing silky webs enclosing branch tips in October, it is fall webworms. Our bagworm guide covers the evergreen side of the story.
Their favorite hosts read like a North Texas greatest-hits list: pecan, hickory, walnut, elm, maple, sweetgum, redbud, mulberry, and persimmon. Pecans are the big one. If you have a pecan in the yard, expect webs.
What the webs actually do to your tree
By the time the nests get big, your tree has already done a full season of photosynthesis. It banked the energy. A healthy mature tree that gets partially defoliated in October leafs out fine the next spring. That is why arborists call webworm damage cosmetic: ugly, not fatal.
The exceptions are real, though. A young tree planted this fall or last spring has a small canopy and a small energy reserve. Stripping a big share of its leaves hits it harder, which is one reason our planting guide stresses protecting new trees their first year. A tree that is already stressed, from drought, construction damage, or root compaction, has less margin. And the same tree getting stripped three or four years in a row can start to thin out and decline.
Pecan growers get one more reason to care. Heavy late-summer defoliation can reduce the current season's nut fill on trees grown for harvest. A backyard pecan with a few webs is fine. An orchard row covered in nests is a different conversation.
The best control is a pole pruner
Skip the spray rig. The most reliable webworm control is physical, and it costs nothing.
Prune the nests out. Use a pole pruner to cut the branch six to twelve inches below the nest, bag the whole thing, and put it in the trash. Do not drop the nests on the lawn. The larvae will crawl right back up the trunk. This works best when the nests are small, so do not wait until October to start looking.
The lazier option works too. Tear the nest open with a stick or a long pole. An opened nest loses its protection, and birds, parasitic wasps, and predatory insects finish the job. This is the move for nests you cannot reach with a pruner.
If you do spray, timing and product matter. Bt, Bacillus thuringiensis, is the low-impact option that works on young feeding larvae. The problem with spraying is the silk itself: the nest sheds contact insecticide, so hosing an intact nest from the driveway mostly wastes money. The spray has to soak through the web, or you tear the nest open first. And skip late-fall sprays entirely. By then the larvae are done feeding and nothing you spray does any good.
What not to do: do not top the tree, do not cut out big structural limbs over webworms, and do not confuse this with a disease problem. Webs on the branch tips in fall are a pest issue with a physical fix, not a reason for surgery. If you are unsure what you are looking at, our dead-or-dormant checks and the signs a tree needs removal guide help sort pest damage from real decline.
When to actually worry
Call it in when the tree is young, when the same tree gets hit hard year after year, or when nests cover a third or more of a small tree's canopy. That is when a quick assessment earns its keep: it tells you whether you are looking at a cosmetic season or a tree that needs real help. Do not cut anything big over webworms alone. If a large limb has to come out for structural reasons, that is removal territory, and it deserves a professional look first.
And if the tree is already in rough shape, drought stress, a leaning trunk, dead limbs mixed in with the webs, treat the whole picture, not just the webs. Water deep during dry spells the way our drought watering guide describes, keep the mulch ring right, and let the tree recover before you do any heavy pruning.
Common Questions
Are fall webworms the same as tent caterpillars?
No. Eastern tent caterpillars show up in spring, build tents in branch crotches, and crawl out to feed. Fall webworms show up in late summer and fall, build nests that enclose the branch tips, and feed inside the web. Different timing, different insect, different fix.
Will fall webworms kill my tree?
A healthy mature tree, no. The defoliation is cosmetic and the tree refoliates in spring. Young trees, stressed trees, and trees stripped heavily several years in a row are the exception. If nests cover a third or more of a small tree's canopy, get it looked at.
Should I spray the webs?
Usually unnecessary. Prune the nests out or tear them open and let predators handle it. If you spray, use Bt on young larvae early in the season and soak the nest thoroughly. Spraying an intact nest from the ground rarely reaches the larvae because the silk sheds contact insecticides. Skip late-fall sprays; the larvae are done feeding.
Will the webs come back next year?
The moths are native and always around, so nests can show up wherever the moths lay eggs. Removing nests now reduces next year's local population, but it will not make your yard webworm-proof. Walk your trees in August and catch the next round while the nests are small.