Question of the Week – Barklice

This week, the question was: What are all these critters crawling on the bark of this crepe myrtle tree?

These are barklice, AKA barkflies or booklice. This species is probably Cerastipsocus venosus. Barklice are sometimes called “tree cattle,” due to their behavior of moving around in a group like a herd of animals (try moving your finger slowly through the group to witness this behavior). They feed on various foodstuff such as algae, lichen, dead insects, mold, and pollen. They do not feed on living plant tissue. These insects are not pests so don’t worry when you see them around in dense clusters. Instead, enjoy their presence as one of the innumerable species of fascinating wildlife that can exist in your yard. Learn more about barklice here.

This week’s question is from Tom Bilbo, Extension Vegetable Entomologist.