It’s that time of year again — when silken webs start showing up on the tips of your pecans, persimmons, mulberries, and more. Yes, spring webworms are back in business.
If you want to avoid major defoliation (and that ugly, haunted-tree look), here’s what you need to know:
1. What Are Webworms?
Despite the name, webworms are caterpillars, not worms. They build protective silk webs over the ends of branches and feed on the foliage inside. In Houston, we often get two generations — once in spring and again in fall.
Common hosts:
- Pecan
- Persimmon
- Mulberry
- Sweetgum
- Elm
2. Are They Dangerous to the Tree?
Not immediately — but yes, they can do real harm. While healthy trees can usually bounce back from mild defoliation, repeated attacks (especially in combination with drought, poor soil, or disease) can weaken the tree and make it susceptible to more serious problems.
Plus, those webs? Not exactly adding curb appeal.
3. How to Get Rid of Webworms (Without Nuking the Ecosystem)
You’ve got options:
- Tear open the webs early: Exposing the caterpillars to predators (birds, wasps, etc.) is the most natural control
- Prune out affected branches: Only if the infestation is small and isolated
- Apply BT (Bacillus thuringiensis): This biological control is caterpillar-specific and safe for pets, people, and pollinators. Timing is everything — it works best when caterpillars are small and actively feeding.
Avoid broad-spectrum insecticides — they kill beneficial bugs too, and rarely get inside the webs where the caterpillars are hiding.
4. Prevention for Next Year
The best offense is a good defense:
- Keep trees healthy with deep watering and soil care
- Use dormant oil sprays in winter if infestations are recurring
- Consider annual monitoring and treatment if you’ve had major outbreaks before
Think you’ve got a webworm problem? Let’s catch it early. Book a tree health checkup at www.ArboristOnDemand.com.
Matt Latham
ISA Board Certified Master Arborist #TX-3737B
ASCA Registered Consulting Arborist #859
ma************@***il.com
www.arboristondemand.com
