IN LATE SUMMER, it’s fairly common to find weird-looking webs (like the one pictured above) on crabapple and other hard-wood trees. Who weaves these horrid things? Meet Hyphantria cunea, the “Fall Webworm.” More about this caterpillar, and why you needn’t go out on a limb to eradicate it:
Hyphantria lives a well-protected life in the silken, water-proof tent it spins around the leaves it eats. Birds and parasitic wasps are rarely able to penetrate the tents. As the caterpillars require more foliage, they simply expand their tent until an entire branch is enclosed.
What do I do about this furry worm? Basically nothing. You see, here in the Northeast, the webworm emerges only in late summer or early fall. Trees at this time have already prepared themselves for winter dormancy, and couldn’t care less if they have leaves or not. They always recover without a hitch the following spring.
However, the webs are unsightly. To remove them, I either prune off the effected limbs, or sweep the webs with a broom or a stick. As the web comes off the tree, the caterpillars remain attached to it. Webs and their inmates are then disposed of.
Again, you need only remove such a tent for aesthetic reasons. If permitted to live, the colony will feed for 4-8 weeks, then migrate downward and pupate in the soil. In spring they will emerge as dusky-white nocturnal moths.
Their are two races of Hyphantria: blackheaded and redheaded. I have the blackheaded type. Both have yellowish bodies. The black dots on their tent are from the waste they produce.
Have you seen the tell-tell signs of the Fall Webworm in your garden? You can let me know in the comments field below.
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Yes, I have these webs on a great big crabapple tree in my backyard. In the past I've sprayed them to no avail. But if the web is waterpoof, that explains why the spray didn't work.
Good to know I don't have to do anything about them.
Kevin you read my mind: I've been wondering about the webs that appear on my apple trees every few years. Someone told me it was the Eastern tent caterpillar, but they are springtime pests, right? Has to be the fall webworm you described.
Kevin Lee Jacobs says
Eric – yes, sprays are mostly ineffective on these pests in their tightly-woven quarters. Even birds and wasps are thwarted by the webbing.
Adele – Eastern caterpillar emerges in spring, and can cause real damage them. The fall webworm is basically harmless. I remove nests purely for aesthetic reasons. (And in truth, I don't kill the worms — just relocate them to the forested area of my property).
Web worms are a favorite of bats and black- and yellow-billed cuckoos. Leave them for the wildlife.
Kevin Lee Jacobs says
Anonymous – that's good to know. I've left most of mine them in place.
I am a kid who found a cute little web worm today I am keeping it for a pet thank you for teaching me about them.
Thank you for saving me from certain disaster!
I found some wicked looking bug-tents hanging in my trees. Everybody I know has something ugly to say about it – they’ll kill every tree in sight! they’ll multiply so fast they’ll infest your entire garden within a week! the only way to get rid of them is to burn them out with kerosene after dark on a moonless night!
I arranged for a couple of people to come tomorrow and help me with this. My plan was sketchy at best, mostly a few half-formed ideas involving a saw, a tarp, some rope, extra-hefty garbage bags . . . oh, and hats, very large hats, in case those tents burst open over our heads. I figured maybe I’d better do a little research tonight.
And that’s when I found your article. Now we can leave the paraphernalia in the shed and sit around on the deck all day, sipping something fine, and talking about subjects far more pleasant than sticky tents filled with wiggly webworms! Bless you!
Kevin Lee Jacobs says
Averasha – Nice to meet you.
Annie – You are right. Much better to sit around drinking wine than to worry about tent caterpillars. The pests attacked two of my crabapple trees late last summer. Both trees resumed their normal beauty the following spring.
Garage Door Repair Revere says
I have also these webs in my home garden and I want to remove them. But how I do not know?
Kevin Lee Jacobs says
GDRR -No need to remove a web except for the sake of appearance. As I mentioned in the article, you can use a broom to remove a web. A power-washer should work, too. Otherwise you’ll have to clip the branch, which will alter the shape of your tree. Again, the caterpillar is only a temporary nuisance; the tree will resume its normal beauty in the spring.
When I was a kid we used to burn them out of our crab apple trees using long cones of rolled up newspaper – though I don’t know if it was for aesthetics or out of ignorance. I have never bothered on my own property and wouldn’t use an insecticide. So glad to know that my instinct was right! Great post. Thanks.
It seems to me the trees mostly mentioned here are fruit trees. I have a nice condo of webworms forming in some redbuds. Coudl these be something else or are all of the webs inhabited by the same type of pest?
Kevin Lee Jacobs says
Hi Candy – The webworm can inhabit any hardwood tree, including redbud. No need to do anything about it — your tree will resume its usual beauty next spring.
Are Fall webworms different from regular tent caterpillars. I have had an infestation this summer on an evergreen bush and it appears to have killed much of the foliage. These are the ones that hang on the bush in a cone shape and don’t actually leave tents. HELP! Thanks, Patricia
Kevin Lee Jacobs says
Hi Patricia – From what I know, tent caterpillars make their tents in the spring, just as trees are leafing out. Webworms make their tents in the fall. Both types feed on deciduous trees, not evergreens. The fall webworm is annoying, but its damage is only temporary.
i love these fall webworms cause they r the most fun insects 2 capture and feed and take care of
I’ve been cutting webworms out of my Yoshino Cherry trees for years. Every year I cut out at least 20 to 30 webs. I try to get them when the webs are very small so I don’t have to cut as much of the branch. I felt that if I let them pupate in my soil I’ll be overrun by them in the future. I don’t see any of my neighbors having any webs in their trees. They love the cherry trees though. I think it’s about late July, early August when I see the first of them.
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Kathy Baker says
Hey Kevin I have a question about webworms,is it true that the more of their webs you see in trees it tells you what kind of winter you’ll have?
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Help! 1st full year at my house in Northern Oklahoma and these webworms are terrible. We have a mostly wooden home and our neighbor has Pecan trees very close. The worms are EVERYWHERE! They’re so bad on my porch and eves that they’re dropping on us as we walk in the house. They cover our door frames, deck, cars overnight, walkway, and gutters. It’s truly a page out of a Stephen King novel. I’m worried about them feasting on our wooden house. Do they just eat live tree foliage or do I have a bigger problem here? We’ve tried pesticide and I believe that made them healthier and multiply. Because our house is wooden, we don’t want to burn them, but I want them GONE!
Any information you have would be great. Thank you for being the most informative thus far.
I live in central Oklahoma and have been overrun by the webworms this year. Worse I have seen it in 5 years since I moved here. Tried insecticides, which i hate to do, but they keep multiplying and not just in my yard but everywhere aound here. Today I took my pressure washer and put extensions on it and shot the webs out of the trees! Worked great! Next spring before the leaves come out on the trees I will spay them with dormant oil like I have read and see if this prevents the moths from laying the eggs, like they say. Fingers are crossed.
I live in central Oklahoma as well and yes, they are horrible this year. The droppings are disgusting. My son just installed a new pool and is having to use 3 times as much chemicals because of this nasty worm poop! Today we are spraying Sevin (contains Carbaryl) which is recommended specifically for these worms. We will also use Neem oil early spring or summer to hopefully get rid of these.
In 2012, Patricia wrote she was having an issue with a worm in her evergreen tree. Those are not the same as the Fall webworm. They are known as bag worms and need to be removed from the evergreen trees as they will kill the tree.
I was doing research today on the Fall Web Worm (local residents call then bag worms) and bag worm and Army worm (another type). thus I found out the difference. We do have a real outbreak of Fall Web Worms near Oklahoma City.
To dispose of the evergreen bag worm, pick it off the limb, put it into soapy water to soak and kill the larvae/pupae inside, then a plastic bag into the trash.
I had a neighbor inquire to me whether webworms could potentially be a threat to a home as they are blowing onto the side of his house out of his big hickory tree in large numbers. Theoretically, if it was made from a raw hardwood or maybe an untreated fiberboard wood product, I suppose they could consume it, but the surface is painted and treated, so I can’t imagine it actually being an issue. We grew up with them in trees my whole life and just never really thought about it, seems completely improbable, but to put his mind at ease, can anyone confirm that with me?
i live in northern washington and these catepillars are in trees in late spring when trees are flourishing…I clip the nasty thing off and burn the whole branch…i could not see doing nothing….they expand and thet cant be good for the tree….