Why Is There White Webbing on My Tree Trunk?

Understanding Bark Lice on Houston Trees — Friend or Foe?

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Webbing on Trun

A Sign of Nature at Work

If you've noticed silky white webbing covering the trunk of a tree, don't panic. While it may look alarming at first, it's often caused by bark lice — harmless insects that actually play a beneficial role in your landscape.

Bark lice (also called Psocids) feed on algae, fungi, lichen, and other organic material growing on the bark. Think of them as nature's cleaning crew, helping keep the bark surface clean without harming the tree itself.

What Is the White Webbing?

Homeowners are often surprised to wake up in late summer and find tree trunks wrapped in a thin layer of white webbing, almost as if someone decorated the tree overnight for Halloween.

This unusual sight is commonly called the “Ghost Web” phenomenon. The webbing serves as a protective covering for colonies of bark lice while they feed and move across the bark surface. Although it may look dramatic, it is completely harmless to the tree and typically disappears within a few weeks.

Are Bark Lice Harmful?

No. Bark lice do not feed on the tree, bore into the wood, or damage healthy bark. In fact, their presence is often associated with a thriving natural ecosystem.

These insects are most commonly found in environments with adequate moisture and abundant organic growth on the bark. Seeing bark lice can actually be an indication that your landscape supports a healthy balance of beneficial organisms.

Bark Lice on trunk of tree

When Should You Be Concerned?

Bark lice themselves are not a problem, but a sudden increase in their numbers may sometimes draw attention to underlying environmental conditions such as:

  • Drought stress
  • Soil compaction
  • Reduced air circulation
  • Excessive moisture or humidity
  • General tree stress

While the insects are not causing these issues, they may be taking advantage of conditions that encourage algae and fungal growth on the bark.

What Should You Do?

In most cases, the best approach is to leave bark lice alone. They will naturally move on once their food source is depleted.

To keep your trees healthy:

  • Water deeply during dry periods.
  • Maintain healthy soil with proper mulching and, where trees are stressed, deep root fertilization.
  • Avoid unnecessary pesticide applications.
  • Schedule routine tree inspections to identify potential stress factors before they become serious problems.

If you notice declining foliage, dieback, or other signs of tree stress in addition to bark lice activity, an ISA Certified Arborist can help determine whether an underlying issue needs attention. Reach out to our team, and we'll take a look.

The Bottom Line

Bark lice may look unusual, but they're more friend than foe. Their presence is often a sign of a healthy, functioning ecosystem — and that mysterious white webbing is usually just nature's way of reminding us that even the smallest creatures have a job to do.

Frequently Asked Questions

Is bark lice harmful?

No. Silky white webbing on a trunk is almost always bark lice — harmless insects that clean algae, fungi, and lichen off the bark and then move on within a few weeks. They don't feed on the tree, bore into the wood, or damage healthy bark, so there's nothing to treat. If you're seeing the webbing alongside declining foliage or dieback, though, that points to a separate stress issue worth a professional look.

How can I get rid of bark lice?

The honest answer is that you don't need to — and you're better off not trying. Bark lice leave on their own once they've finished feeding, and the “ghost web” disappears with them within a couple of weeks. Pesticides do more harm than good here, since they can wipe out the beneficial organisms bark lice are part of. The best thing you can do is support overall tree health with deep watering and good soil care.

Do bark lice mean my tree is unhealthy?

Usually the opposite — bark lice thrive where there's good moisture and plenty of organic growth, so their presence often signals a healthy, balanced bark ecosystem. That said, a sudden spike can occasionally draw attention to underlying stress like drought or soil compaction. If your tree also looks stressed, a routine inspection can tell you whether anything below the surface needs attention.

When should I call an arborist about bark lice?

Bark lice alone don't warrant a call. But if you spot them alongside thinning or discolored foliage, branch dieback, or dead limbs, those are signs of a deeper problem the bark lice are simply taking advantage of — and dead or hazardous limbs may need professional trimming to keep the tree safe. In that case, contact our team, and an ISA Certified Arborist can evaluate what's really going on.

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