Webworms are hanging out in Central Texas trees this year in greater numbers than usual

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Austin (KXAN) — What’s that large cobweb-looking thing cloaking the tree in your yard? Why do the trees on your drive to work look like they’ve been draped with a thin white web?

Entomologists say it’s webworm season.

What is a webworm?

Webworms — or Fall webworms or Hyphantria cunea — are young moths who live out their time as caterpillars in silken enclosures they spin in plants.

Brown says the moths appear as a “drab, creamish brown color”

Webworms start off as eggs, and when they hatch, they begin spinning their silken webs.

Webworm caterpillars at the Texas A&M AgriLife Extension offices in Austin. (KXAN Photo/Alyssa Goard)

“It is a larger amount than we normally see,” explained entomologist Wizzie Brown, who has been fielding calls left and right about trees covered in webs. “Webworms, we have them every year, but it seems like the webs are more noticeable this year than they have been in the past.”

Brown is an extension program specialist with Texas A&M AgriLife Extension Service, the arm of Texas A&M which helps educate farmers, consumers and community members.

“Basically I deal with bugs,” Brown said. Her focus is in Travis County and the surrounding areas.

Brown said that it’s likely a mix of factors led to the large numbers of webworms this year, for example, a combination of ideal temperatures, foliage, and moisture probably played a role.

Texas Parks and Wildlife Department explained that these insects are a native species, but TPWD doesn’t do any population monitoring for them as there is no concern for their populations.

Brown says the bugs range in color — from creamy whites, to yellows, and pale greens — and they have tufts of hair coming off of them. The caterpillars can grow to around an inch in size, she said.

“They are fuzzy, you can touch them. They’re not going to sting you, but they do defoliate trees,” Brown said. “A lot of people panic when they see the webs.”

How do they impact plants?

These caterpillars have chewing mouthparts which allow them to eat leaves on plants, Brown explained.

“So the cool thing about these ones — or at least the cool thing, I think — is that they will encompass the foliage that they are eating inside the webbing,” said Brown. “And it’s a way they protect themselves from predators and parasites and they can even protect themselves from pesticides.”

She noted that most trees can bounce back when the webworms are confined to one spot. When there is a larger infestation, however, things can get more dangerous for the trees as their leaves get damaged.

Bill Ree, an extension program specialist for Pecan pest management at Texas A&M AgriLife Extension explained that these webworms can be found across much of the state of Texas.

“I see it as more of an issue for the urban areas,” he said, noting that commercial growers typically use pesticides that deter webworms.

What you can do to get rid of them?

“In the caterpillar stage, they are completely inside of the web — and that’s the damaging stage — so if you want to control them, you have to get inside of that webbing,” Brown explained. “Even if you do a pesticide treatment, you still have to open that web, because otherwise the pesticide is going to be on the outside of it and it’s not going to do anything for the caterpillars.”

If you want to get rid of webworms, Brown said that a good option is simply opening up the web to allow for lizards, wasps, or birds to get in and eat them. You can also prune the infested parts of the tree away or use a high-pressure water spray to get holes in the web.

“Usually just poking holes in it is enough to manage them, but we will have multiple generations of these webworms in a year — anywhere from two to four generations — so it’s quite possible that they will continue to be on trees throughout the summer.”

She noted that even if the webworms are dead, the webs will remain in trees.

Webworms in a tree in Austin. (KXAN Photo/Alyssa Goard)

“So don’t panic if you see the webs,” she said.

Brown has even had success with knocking them out of trees using a stick.

“If you choose the stick method, you want to wear a hat because the caterpillar poop will fall on your head otherwise,” Brown said

She explained that if nothing is done to manage webworms, they can return in future years.

“So if they are in that last generation in the fall and they start to lay their eggs, those will last throughout the wintertime and they’ll hatch out of that same tree the next year,” she said.

Brown said these insects can be found on trees from around April through the fall in Texas.

“They’re called Fall webworms because the fall stages are usually the most damaging because they are trying to beef up for winter and get prepared,” she said.

So keep your eyes out for these webs in trees for the next few months,. Webworm season is not even close to over yet.

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