Horticulture News: Odd little barklice

By Adam Leonberger, Published:

This past week I encountered something I’d only heard about.

“Herds” of barklice can be found on tree trunks during the summer. These soft-bodied insects have long antennae and a banded body. Although these insects resemble aphids and are called “lice,” they are not pests or parasites of either plants or animals. 

Members of this group (Order Psocoptera) have chewing mouthparts that are used to feed on fungi, algae, dead plant tissue, and lichen. Most species live alone or in small groups, however two species are gregarious (stay together in large groups).

One species (Archipsocus nomas) can cover tree branches with a light layer of silk. The webbing from barklice is rarely found on the foliage, which differs from spider mites and certain caterpillars.

The other species (Cerastipsocus venosus) found on the bark of trees moves as a group resembling a herd of animals or flock of birds. They are a curiosity but cause no harm and can provide some entertainment, if you have tendencies toward wrangling.

They usually stay in a cohesive unit but will disperse if you move a finger toward them. When you take it away they will move back together.


Barklice are harmless, and the webbing formed by some species does not harm the trees on which it occurs. The presence of barklice indicates that a suitable habitat for them exists.

Since the tree-dwelling species eats fungus, lichen, and organic debris, they could be viewed as beneficial insects. Control of such insects is unnecessary; however, if you consider the webbing to be unsightly, you could use a high-pressure stream of water to remove it from the trees.

For more information on this and other horticultural issues, contact the Franklin County Extension Office, 502-695-9035, or Adam.Leonberger@uky.edu.

Want to leave your comments?

Sign in or Register to comment.