Walking through the neighborhood this weekend I noticed several trees with patches of webbing on their trunks. Barklice are back and doing what they do best; feeding on fungi, algae, dead bark and other organic materials.
Barklice are not true lice and are harmless to humans and pets. They are small, soft-bodied insects with two-pairs of well-developed wings in the adult stage, but the adults of some species can have reduced wings or none at all. Eggs are laid singly or in clusters and undergo simple metamorphosis (the young resemble the adults) and pass through six nymphal stages (instars) before becoming adults.
There are two species commonly found in the Texas Gulf-coast region.
- Web-spinning barklice: Archipsocus nomas less than 1/8 of an inch long, brownish in color and may or may not have wings. The actual insects are rarely seen, but their communal silken webs commonly found on the bark of trunks and branches are easy to identify. The webbing from barklice is rarely found on the foliage, which differs, from mites and caterpillars.
- Aggregating barklice: Cerastipsocus venosus adults can reach ¼ of an inch in length, are winged and black in color. This species does not produce a web and the clusters of barklice move slowly together like a herd of cattle on the bark.
These insects pose no threat to the health or vigor of the tree. The presence of barklice indicates that a suitable habitat for them exists. They are viewed as beneficial insects since they eat fungus and other organic debris. The control of barklice is not necessary; however if a customer/homeowner considers the webbing unsightly a high-pressure stream of water will remove the webbing and dislodge the insects from the tree (no insecticide treatments are required).