Tree Webbing Without Leaf Damage: Harmless Bark Lice (Psocids)

Fine silvery webbing on tree trunks and large limbs—but not leaves—is bark lice (psocids), also called “tree cattle.” They’re scavengers, not pests.

What They Do

• Feed on lichens, fungi, dead bark, and organic debris.
• Produce protective webbing with silvery sheen.
• Groups of hundreds may be seen under webbing.

No Control Needed

Beneficial: clean up excess lichens and dead material. Populations peak in fall, decline in winter.

If Webbing Bothers You

• Blast off with strong water stream.
• Insecticides unnecessary and harm beneficials.

More Info

Auburn University bark lice guide