A beneficial insect
We had our first case of bark lice come in the nursery today. This insect makes a fine white webbing over the trunks and branches of oaks but can inhabit other kinds of trees also. They do no harm to your tree so you do not need to kill them. We have had customers that have been told by other plant places to spray and kill them. They say that because they believe they are harmful. They are not harmful at all. 
Bark lice will inhabit the bark and eat residue from other insects and generally clean up the tree. The bark lice will do their work and when they are finished will eat their own webbing and will be gone as quickly as they came.
This photo was taken last year on our oaks at the nursery.
Thanks for the tip! I was also told that they should be killed but now I will let them be.
Is the bark lice the same thing as the white webbing that forms in the branches? I think those are worms but I am not certain. I can remember when I was little my Dad would take a flame to the webs in the branches and burn those suckers out.
Enjoy your weekend!
~Jason
Reply to this
Jason,
Those other insects are tent caterpillars. They produce the webbing that encompasses the foliage. They do damage! You can spray with Bt or break up the webbing with a stick and wasps will hunt them down and eat them. That is one very good thing that wasps do for us.
Reply to this
That is the BEST photo I have seen of bark lice. No books or other websites have shown the close up look and texture of the webbing. Good job.
Reply to this
I am delighted to have found this article and photo. We have three trees in our garden that look just like this. My husband said they are master builders...wonder when they will be finished cleaning? At least we will not worry now.
Reply to this